Tube Radio Power Supply

[Dave.H]

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode.
i was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to
the 120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

 

[Tim Wescott]

On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).

A type 80 would be period correct, but you'd have to get a transformer
for it.

Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.

5 9-volt batteries, snapped end-to-end, is one of the accepted methods
for powering one of these critters, and apparently has good life.
Rechargeables should work fine, and save you $$ on batteries if you end
up using the radio a lot.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

 

[Dave.H]

On Jul 22, 1:35 am, "Dave.H" <the19...@googlemail.com> wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode.
i was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to
the 120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

Forgot the link to the power supply plans: http://www.antiqueradio.org/bsupply.htm

 

[Jonathan Kirwan]

On Mon, 21 Jul 2008 11:08:15 -0500, Tim Wescott <tim@seemywebsite.com>
wrote:

On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).

A type 80 would be period correct, but you'd have to get a transformer
for it.

Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.

5 9-volt batteries, snapped end-to-end, is one of the accepted methods
for powering one of these critters, and apparently has good life.
Rechargeables should work fine, and save you $$ on batteries if you end
up using the radio a lot.

I used 45-volt phone supplies in some of what I did, many years ago
when I'd scrounge them from phone companies. They were a 'box',
basically of AA carbon rod batteries soldered together. Those worked
very well and lasted and I'd use two to get a 90V plate supply. I'd
never tried to use stacked 9V, though. My memory is struggling, but I
think I used 5U4s and 6AU4s for diodes, pulled from old tvs.

By the way, I gave away a box of tube pulls I'd collected that
literally filled a 3' x 3' x 2.5' box to a radio club in the east,
about a decade ago. Included very old tubes I'd collected back in
1965: including pulls from old WW II (1944 and after) radar units
(sellenium rectifiers, selsyn motors, VR-150s, waveguides, ... lots of
interesting things there.) Separately, a 4CX1000A I had also was sent
to them.

I never did use the small, 2V filament tubes, though. Just 6.3/12.6V
stuff as far as I recall. (Thinking about tubes reminded me that
estimating grid leak resistor values was one of the early mysteries
for me, since I had remembered reading that there was essentially no
current so I just sat there scratching my head with ohms law and
nothing to plug in for current and yet knowing that I needed to
somehow bias it.)

Jon

 

[Michael Black]

On Mon, 21 Jul 2008, Tim Wescott wrote:

On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).

A type 80 would be period correct, but you'd have to get a transformer
for it.

Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.

But that sort of devolves to the fact that the regen is seen as a simple

receiver, so nobody wants to complicate them.

Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators. Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.

So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one. You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna. You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen. Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.

Build it like the oscillator it is, using voltage regulation and isolation
from the antenna and using a nice solid wire for the coil, along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.

Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.

Michael

5 9-volt batteries, snapped end-to-end, is one of the accepted methods
for powering one of these critters, and apparently has good life.
Rechargeables should work fine, and save you $$ on batteries if you end
up using the radio a lot.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

 

[Tim Wescott]

Michael Black wrote:

On Mon, 21 Jul 2008, Tim Wescott wrote:

On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).

A type 80 would be period correct, but you'd have to get a transformer
for it.

Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.

But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.

Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators. Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.

Some of those designs from the '20s and '30s used _good_ components, at
least for the day. There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.

So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.

Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.

You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.

Was, back in the day when the bands weren't crowded. One is abjured not
to now, at least by the ARRL.

You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen. Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.

Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.

Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.

Michael

I suspect that everything you have to say is on track technically,

except for my above objections and/or apologies to your perceptions of
prevailing opinions.

I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.

It'd be fun, though.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Dave.H]

On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:

Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:

On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

(note that nearly everything I'm going to say is from book learning, not
practical experience.  Size your grain of salt appropriately).

A type 80 would be period correct, but you'd have to get a transformer
for it.

Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions.  Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.

But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.

Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators.  Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.

Some of those designs from the '20s and '30s used _good_ components, at
least for the day.  There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.



So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.

Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.

You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.

Was, back in the day when the bands weren't crowded.  One is abjured not
to now, at least by the ARRL.



You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen.  Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.

Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.

Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.

   Michael

I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.

I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.

It'd be fun, though.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says..
See details athttp://www.wescottdesign.com/actfes/actfes.html

I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer. I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

 

[Tim Wescott]

Dave.H wrote:

On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:
Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators. Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day. There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.



So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.

You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded. One is abjured not
to now, at least by the ARRL.



You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen. Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.

I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.

It'd be fun, though.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer. I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

That should work. You'll have crappy regulation with that circuit, and
the 'natural' voltage of a capacitor-input supply like that is between
the line voltage and line voltage times root-2, so 117V to 164V. They
'fix' that problem with R2 and R3, although at first blush I don't trust
their specified power rating for R2 -- if you need 5W for R3, which is
about the same value as R2 and carries less current, why can you get
away with 2W for R2?

If you have any spare filament transformers around you can use one for a
choke-input supply. With a single diode you should get around 45V with
plenty of ripple; with another spare filament transformer you can pound
the ripple down a bit.

A (fun) alternative if you have the circuits knowledge would be to
replace R2 on with a regulated supply. You could go with something as
simple as a neon light (or zener) connected to the grid of a triode (or
base of a BJT), up to a fancy actively regulated supply using a couple
of tubes or an LM723.

I'd start with what you're proposing, though, and go from there.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Tim Wescott]

Dave.H wrote:

On 23 Jul, 00:01, "Dave.H" <the19...@googlemail.com> wrote:
On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:



Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators. Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day. There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.
So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.
You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded. One is abjured not
to now, at least by the ARRL.
You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen. Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.
I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.
It'd be fun, though.
--
Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html
I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer. I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

Also, would it be OK to replace the .05 uF (ceramic) with a polyester
capacitor? I can't seem to find any ceramics with 400 volts rating

Yabbut.

There's a specific safety rating for capacitors that go on the power
line. I can't remember it, but basically for a 120V line you want to
have a cap that's good to something like 630VDC (hopefully someone whose
done this recently will jump in here).

For a home job in a fire proof enclosure, with the cap on the 'other'
side of a transformer, 400V is probably OK -- but I didn't say that in
any professional capacity, yer on your own for safety related stuff.

You _are_ going to fuse the input side, right?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Dave.H]

On 23 Jul, 00:01, "Dave.H" <the19...@googlemail.com> wrote:

On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:



Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:

On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode.. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

(note that nearly everything I'm going to say is from book learning, not
practical experience.  Size your grain of salt appropriately).

A type 80 would be period correct, but you'd have to get a transformer
for it.

Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions.  Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.

But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.

Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators.  Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.

Some of those designs from the '20s and '30s used _good_ components, at
least for the day.  There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.

So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.

Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.

You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.

Was, back in the day when the bands weren't crowded.  One is abjured not
to now, at least by the ARRL.

You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen.  Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.

Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.

Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.

   Michael

I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.

I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.

It'd be fun, though.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer.  I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

Also, would it be OK to replace the .05 uF (ceramic) with a polyester
capacitor? I can't seem to find any ceramics with 400 volts rating

 

[Tim Wescott]

Dave.H wrote:

On 23 Jul, 11:03, "Dave.H" <the19...@googlemail.com> wrote:
On 23 Jul, 02:19, Tim Wescott <t...@seemywebsite.com> wrote:



Dave.H wrote:
On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:
Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators. Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day. There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.
So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.
You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded. One is abjured not
to now, at least by the ARRL.
You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen. Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.
I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.
It'd be fun, though.
--
Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html
I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer. I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).
Dave
Australia
That should work. You'll have crappy regulation with that circuit, and
the 'natural' voltage of a capacitor-input supply like that is between
the line voltage and line voltage times root-2, so 117V to 164V. They
'fix' that problem with R2 and R3, although at first blush I don't trust
their specified power rating for R2 -- if you need 5W for R3, which is
about the same value as R2 and carries less current, why can you get
away with 2W for R2?
If you have any spare filament transformers around you can use one for a
choke-input supply. With a single diode you should get around 45V with
plenty of ripple; with another spare filament transformer you can pound
the ripple down a bit.
A (fun) alternative if you have the circuits knowledge would be to
replace R2 on with a regulated supply. You could go with something as
simple as a neon light (or zener) connected to the grid of a triode (or
base of a BJT), up to a fancy actively regulated supply using a couple
of tubes or an LM723.
I'd start with what you're proposing, though, and go from there.
--
Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html
Dave
Australia
,,
When modifying the circuit to output 45 volts, do I replace R3 with,
for example 2800 ohms, if there is an output of 160v? Or do Ieave R3
in?

Thanks
Dave
Auustralia

You juggle the values of R2 and R3 to get good regulation, low
dissipation, and low ripple.

You want the highest value of R3 that'll get you by when the radio's
connected.

Pay attention to dissipation.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Tim Wescott]

Dave.H wrote:

On 23 Jul, 02:24, Tim Wescott <t...@seemywebsite.com> wrote:
Dave.H wrote:
On 23 Jul, 00:01, "Dave.H" <the19...@googlemail.com> wrote:
On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:
Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators. Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day. There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.
So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.
You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded. One is abjured not
to now, at least by the ARRL.
You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen. Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.
I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.
It'd be fun, though.
--
Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html
I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer. I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).
Dave
Australia
Also, would it be OK to replace the .05 uF (ceramic) with a polyester
capacitor? I can't seem to find any ceramics with 400 volts rating
Yabbut.

There's a specific safety rating for capacitors that go on the power
line. I can't remember it, but basically for a 120V line you want to
have a cap that's good to something like 630VDC (hopefully someone whose
done this recently will jump in here).

For a home job in a fire proof enclosure, with the cap on the 'other'
side of a transformer, 400V is probably OK -- but I didn't say that in
any professional capacity, yer on your own for safety related stuff.

You _are_ going to fuse the input side, right?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

Yes, what fuse rating should I use?

Thanks
Dave
Australia

Um uh, um.

No higher than the current capacity of the xformer primary, for sure.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Dave.H]

On 23 Jul, 02:24, Tim Wescott <t...@seemywebsite.com> wrote:

Dave.H wrote:
On 23 Jul, 00:01, "Dave.H" <the19...@googlemail.com> wrote:
On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:

Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience.  Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions.  Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B..
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators.  Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day.  There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.
So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.
You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded.  One is abjured not
to now, at least by the ARRL.
You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen.  Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
   Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.
I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.
It'd be fun, though.
--
Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html
I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer.  I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

Also, would it be OK to replace the .05 uF (ceramic) with a polyester
capacitor?  I can't seem to find any ceramics with 400 volts rating

Yabbut.

There's a specific safety rating for capacitors that go on the power
line.  I can't remember it, but basically for a 120V line you want to
have a cap that's good to something like 630VDC (hopefully someone whose
done this recently will jump in here).

For a home job in a fire proof enclosure, with the cap on the 'other'
side of a transformer, 400V is probably OK -- but I didn't say that in
any professional capacity, yer on your own for safety related stuff.

You _are_ going to fuse the input side, right?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says..
See details athttp://www.wescottdesign.com/actfes/actfes.html

Yes, what fuse rating should I use?

Thanks
Dave
Australia

 

[Dave.H]

On 23 Jul, 02:19, Tim Wescott <t...@seemywebsite.com> wrote:

Dave.H wrote:
On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:
Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode.. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience.  Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions.  Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators.  Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day.  There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.

So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.

You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded.  One is abjured not
to now, at least by the ARRL.

You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen.  Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
   Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.

I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.

It'd be fun, though.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer.  I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

That should work.  You'll have crappy regulation with that circuit, and
the 'natural' voltage of a capacitor-input supply like that is between
the line voltage and line voltage times root-2, so 117V to 164V.  They
'fix' that problem with R2 and R3, although at first blush I don't trust
their specified power rating for R2 -- if you need 5W for R3, which is
about the same value as R2 and carries less current, why can you get
away with 2W for R2?

If you have any spare filament transformers around you can use one for a
choke-input supply.  With a single diode you should get around 45V with
plenty of ripple; with another spare filament transformer you can pound
the ripple down a bit.

A (fun) alternative if you have the circuits knowledge would be to
replace R2 on with a regulated supply.  You could go with something as
simple as a neon light (or zener) connected to the grid of a triode (or
base of a BJT), up to a fancy actively regulated supply using a couple
of tubes or an LM723.

I'd start with what you're proposing, though, and go from there.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says..
See details athttp://www.wescottdesign.com/actfes/actfes.html

I'll probably experiment with regulation circuits when it's up and
running.

Dave
Australia

 

[Dave.H]

On 23 Jul, 11:03, "Dave.H" <the19...@googlemail.com> wrote:

On 23 Jul, 02:19, Tim Wescott <t...@seemywebsite.com> wrote:



Dave.H wrote:
On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:
Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience.  Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions.  Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators.  Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day.  There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.

So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.

You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded.  One is abjured not
to now, at least by the ARRL.

You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen.  Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
   Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.

I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.

It'd be fun, though.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer.  I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

That should work.  You'll have crappy regulation with that circuit, and
the 'natural' voltage of a capacitor-input supply like that is between
the line voltage and line voltage times root-2, so 117V to 164V.  They
'fix' that problem with R2 and R3, although at first blush I don't trust
their specified power rating for R2 -- if you need 5W for R3, which is
about the same value as R2 and carries less current, why can you get
away with 2W for R2?

If you have any spare filament transformers around you can use one for a
choke-input supply.  With a single diode you should get around 45V with
plenty of ripple; with another spare filament transformer you can pound
the ripple down a bit.

A (fun) alternative if you have the circuits knowledge would be to
replace R2 on with a regulated supply.  You could go with something as
simple as a neon light (or zener) connected to the grid of a triode (or
base of a BJT), up to a fancy actively regulated supply using a couple
of tubes or an LM723.

I'd start with what you're proposing, though, and go from there.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html
Dave
Australia
,,

When modifying the circuit to output 45 volts, do I replace R3 with,
for example 2800 ohms, if there is an output of 160v? Or do Ieave R3
in?

Thanks
Dave
Auustralia

 

[Dave.H]

On 23 Jul, 00:01, "Dave.H" <the19...@googlemail.com> wrote:

On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:



Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:

On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:

I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode.. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)

Thanks,
Dave
Australia

(note that nearly everything I'm going to say is from book learning, not
practical experience.  Size your grain of salt appropriately).

A type 80 would be period correct, but you'd have to get a transformer
for it.

Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions.  Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.

But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.

Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators.  Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.

Some of those designs from the '20s and '30s used _good_ components, at
least for the day.  There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.

So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.

Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.

You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.

Was, back in the day when the bands weren't crowded.  One is abjured not
to now, at least by the ARRL.

You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen.  Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.

Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.

Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.

   Michael

I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.

I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.

It'd be fun, though.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html

I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer.  I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

Is the 117Z4GT an 8 pin octal? Here: http://tubes.mkdw.net/sheets/127/1/117Z4GT.pdf
It looks like it says 6 pin octal.

Thanks
Dave
Australia

 

[Tim Wescott]

Dave.H wrote:

On 23 Jul, 00:01, "Dave.H" <the19...@googlemail.com> wrote:
On 22 Jul, 07:36, Tim Wescott <t...@seemywebsite.com> wrote:



Michael Black wrote:
On Mon, 21 Jul 2008, Tim Wescott wrote:
On Mon, 21 Jul 2008 08:35:13 -0700, Dave.H wrote:
I have an old regen radio that requires 45 volts for the B+. I was
looking at plans for building a mains power supply, with a solid state
(1N4003) rectifier. Since the radio I'm building it for as tube bases,
(type 30) I thought of using a tube rectifier in place of the diode. i
was wondering what tube would be best for this, I was looking at the
117L7GT since it has a 117 volt filament could run it in parallel to the
120 volt power input (I'm running the whole thing of a stepdown
transformer I bought for another tube radio, and has isolated primary
and secondary)
Thanks,
Dave
Australia
(note that nearly everything I'm going to say is from book learning, not
practical experience. Size your grain of salt appropriately).
A type 80 would be period correct, but you'd have to get a transformer
for it.
Regens were very picky about the power that they'd run off of -- you get
all sorts of oddball power supply/radio interactions. Most designs that
I've seen that use the 2V battery powered filaments use a pair of dry
cells and a rheostat for filament (A) power and a 45V battery for B.
But that sort of devolves to the fact that the regen is seen as a simple
receiver, so nobody wants to complicate them.
Given that they are at times an oscillator, and the rest of the time often
on the cusp of oscillation, it's always a surprise that few have treated
them like oscillators. Obviously in the twenties or thirties the cost
of components was a big factor, but in more recent decades parts have
become cheap.
Some of those designs from the '20s and '30s used _good_ components, at
least for the day. There was much that wasn't understood about things
like wire size, but much was, and was published in the amateur
literature of the day.
So you don't see voltage regulation on a regen, even though an oscillator
would tend to have one.
Per my small stack of ARRL literature, amateur radio builders didn't
discover the use of gaseous voltage regulator tubes until the early -
mid thirties; even by then the regen was seen as a 'simple' receiver, to
be replaced by a superhet as soon as you could afford it.
You wouldn't have an oscillator driving an
antenna directly, well not in decades and decades, but it's seen as
acceptable to connect the regen directly to the antenna.
Was, back in the day when the bands weren't crowded. One is abjured not
to now, at least by the ARRL.
You'd not
build an oscillator on something that wasn't mechanically stable, or
use tiny wire for the oscillator coil, but that sort of thing becomes
acceptable for a regen. Don't bother with DC on the filament (if it's a
tube regen), because it's too much work; live with any modulation that
comes from 60Hz on the filament.
Build it like the oscillator it is, using voltage regulation and
isolation from the antenna and using a nice solid wire for the coil,
along with
multiple bypass capacitors and all the rest, and it's bound to help
the overall useability of the regen.
Charles Kitchen, who's done quite a bit of work on solid state regens,
going back to the original regen work and then trying to bring it into
the solid state age, has put in at least simple regulators, the cost
to the project is really insignificant.
Michael
I suspect that everything you have to say is on track technically,
except for my above objections and/or apologies to your perceptions of
prevailing opinions.
I also suspect that by the time you get a regen to _really_ work well
you will be approaching superhet complexity, and probably with a really
inscrutable circuit.
It'd be fun, though.
--
Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html
I've found another tube that hasn't got the amplfier section, which I
didn't need, the 117Z4GT. Still has a 117v heater, so I don't need a
transformer. I am going to build the whole thing in a plastic box for
safety, with the tube sticking out the top. I might use binding posts
for the B+ 45v, and filament (powered by two "D" Cells, with 18 ohm
resistor).

Dave
Australia

Is the 117Z4GT an 8 pin octal? Here: http://tubes.mkdw.net/sheets/127/1/117Z4GT.pdf
It looks like it says 6 pin octal.

Thanks
Dave
Australia

Regular octal pattern, with two pins deleted. You can use a regular
8-pin socket, or if you plan on volume manufacture you can special order
sockets with those holes blanked out.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html