E
Eeyore
Guest
Phil Allison wrote:
Graham
Apologies. I was getting over-excited at the prospect.
Graham
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E
Eeyore
Guest
Kevin Aylward wrote:
taking the gate input capacitance off that node.
Graham
Class A buffer for me, as for you too it would seem. Makes all the differenceJohn Larkin wrote:
mrdarrett@gmail.com wrote:
Are there any technical advantages that lateral mosfets have over
BJTs in audio amplifier design?
Do lateral mosfets offer lower theoretical THD+N over the entire
audio spectrum than BJTs for instance?
Either needs lots of negative feedback to be really linear, so THD+N
depends on the overall circuit design, not much on the final output
devices. It's generally easier to drive mosfets than bipolars, but in
audio bandwidths it doesn't matter much.
I don't really understand to what aspect you are referring to with this last
phrase. The low drive requirements of mosfets can be the difference between
a slow output triple and a simple low current class A buffer. This has a
major effect in the stabilization of the amp.
taking the gate input capacitance off that node.
Graham
E
Eeyore
Guest
John Fields wrote:
'you made it up'.
Therefore there's absolutely no point in doing so.
Smarter people than you here understand what I'm saying.
Graham
Oh you're becoming like Phildo in aapl-s. Faced with evidence he simply saysFinally, I'll add that even if you did manage to, somehow, produce the
documentation I'd suspect that, from your hemming and hawing and
absolute refusal to publish anything concrete, here, for us to view, it
wasn't work done by you in the first place.
'you made it up'.
Therefore there's absolutely no point in doing so.
Smarter people than you here understand what I'm saying.
Graham
E
Eeyore
Guest
John Fields wrote:
It's 500W in SOT227/ISOTOP
http://www.magnatec-uk.com/mosdata.shtml
least the majority owner. I've known him for years.YES a British semiconductor maker.
http://www.magnatec-uk.com/latmos.shtml
Graham
Sorry it's dual die 250W in TO-3 but he does some larger devices too.Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
(a) they're not 100 watt - in fact one supplier does a dual die 500W device in
TO-3. With an internal copper heat speader btw.
ONE supplier indeed. How much does that gadget cost?
And how do you get 500 watts out of a TO-3 can? Put it under a fire
hose?
Ask my friend who makes them.
It's 500W in SOT227/ISOTOP
http://www.magnatec-uk.com/mosdata.shtml
Roger Bacon Managing Director of Magnatec and Semelab and I believe the owner or atOf course you're not free to tell us who that might be because the
volume of business that might generate for him would inundate him with
orders he couldn't fill and, therefore, drive him out of business.
least the majority owner. I've known him for years.YES a British semiconductor maker.
http://www.magnatec-uk.com/latmos.shtml
Graham
J
John Fields
Guest
On Sun, 19 Oct 2008 17:56:11 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:
You haven't presented any evidence, all you've said is: "I designed that
piece of equipment." without proving that you did.
Anyone can do that.
---
More balking.
---
I'm sure we all do.
JF
<rabbitsfriendsandrelations@hotmail.com> wrote:
---John Fields wrote:
Finally, I'll add that even if you did manage to, somehow, produce the
documentation I'd suspect that, from your hemming and hawing and
absolute refusal to publish anything concrete, here, for us to view, it
wasn't work done by you in the first place.
Oh you're becoming like Phildo in aapl-s. Faced with evidence he simply says
'you made it up'.
You haven't presented any evidence, all you've said is: "I designed that
piece of equipment." without proving that you did.
Anyone can do that.
---
---Therefore there's absolutely no point in doing so.
More balking.
---
---Smarter people than you here understand what I'm saying.
I'm sure we all do.
JF
J
John Fields
Guest
On Sun, 19 Oct 2008 18:16:56 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:
Well, "NEW PRODUCT UNDER DEVELOPMENT" for both the N channel and P
channel devices means it's not available (unless those are old data
sheets.
In any case, good luck to them.
---
Well, how about that! I'm flabbergasted!!!
JF
<rabbitsfriendsandrelations@hotmail.com> wrote:
---John Fields wrote:
Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
(a) they're not 100 watt - in fact one supplier does a dual die 500W device in
TO-3. With an internal copper heat speader btw.
ONE supplier indeed. How much does that gadget cost?
And how do you get 500 watts out of a TO-3 can? Put it under a fire
hose?
Ask my friend who makes them.
Sorry it's dual die 250W in TO-3 but he does some larger devices too.
It's 500W in SOT227/ISOTOP
http://www.magnatec-uk.com/mosdata.shtml
Well, "NEW PRODUCT UNDER DEVELOPMENT" for both the N channel and P
channel devices means it's not available (unless those are old data
sheets.
In any case, good luck to them.
---
---Of course you're not free to tell us who that might be because the
volume of business that might generate for him would inundate him with
orders he couldn't fill and, therefore, drive him out of business.
Roger Bacon Managing Director of Magnatec and Semelab and I believe the owner or at
least the majority owner. I've known him for years.YES a British semiconductor maker.
http://www.magnatec-uk.com/latmos.shtml
Well, how about that! I'm flabbergasted!!!
JF
J
John Fields
Guest
On Sun, 19 Oct 2008 17:56:11 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:
I'm sure that even the most ignorant of us do.
JF
<rabbitsfriendsandrelations@hotmail.com> wrote:
---John Fields wrote:
Finally, I'll add that even if you did manage to, somehow, produce the
documentation I'd suspect that, from your hemming and hawing and
absolute refusal to publish anything concrete, here, for us to view, it
wasn't work done by you in the first place.
Oh you're becoming like Phildo in aapl-s. Faced with evidence he simply says
'you made it up'.
Therefore there's absolutely no point in doing so.
Smarter people than you here understand what I'm saying.
I'm sure that even the most ignorant of us do.
JF
E
Eeyore
Guest
John Fields wrote:
PRELIMINARY on them. So ?
Graham
I've seen plenty of data sheets for devices in volume production that still sayOn Sun, 19 Oct 2008 18:16:56 +0100, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:
John Fields wrote:
Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
(a) they're not 100 watt - in fact one supplier does a dual die 500W device in
TO-3. With an internal copper heat speader btw.
ONE supplier indeed. How much does that gadget cost?
And how do you get 500 watts out of a TO-3 can? Put it under a fire
hose?
Ask my friend who makes them.
Sorry it's dual die 250W in TO-3 but he does some larger devices too.
It's 500W in SOT227/ISOTOP
http://www.magnatec-uk.com/mosdata.shtml
---
Well, "NEW PRODUCT UNDER DEVELOPMENT" for both the N channel and P
channel devices means it's not available (unless those are old data
sheets.
PRELIMINARY on them. So ?
Graham
M
Michael A. Terrell
Guest
Eeyore wrote:
So, either you are too lazy to look for the final data sheets, or the
company doesn't give a dam about releasing the proper data. Neither
says anything good about the situation.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
I've seen plenty of data sheets for devices in volume production that still say
PRELIMINARY on them. So ?
So, either you are too lazy to look for the final data sheets, or the
company doesn't give a dam about releasing the proper data. Neither
says anything good about the situation.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
J
John Fields
Guest
On Mon, 20 Oct 2008 02:16:48 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:
So, are these products available or not?
I've tried going to their home page but Google says it's not available.
Since you're such good friends with what's-his-name maybe you could give
him a call and report back with all the juicy details like
availability/lead time, price, etc.?
JF
<rabbitsfriendsandrelations@hotmail.com> wrote:
---John Fields wrote:
On Sun, 19 Oct 2008 18:16:56 +0100, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:
John Fields wrote:
Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
(a) they're not 100 watt - in fact one supplier does a dual die 500W device in
TO-3. With an internal copper heat speader btw.
ONE supplier indeed. How much does that gadget cost?
And how do you get 500 watts out of a TO-3 can? Put it under a fire
hose?
Ask my friend who makes them.
Sorry it's dual die 250W in TO-3 but he does some larger devices too.
It's 500W in SOT227/ISOTOP
http://www.magnatec-uk.com/mosdata.shtml
---
Well, "NEW PRODUCT UNDER DEVELOPMENT" for both the N channel and P
channel devices means it's not available (unless those are old data
sheets.
I've seen plenty of data sheets for devices in volume production that still say
PRELIMINARY on them. So ?
So, are these products available or not?
I've tried going to their home page but Google says it's not available.
Since you're such good friends with what's-his-name maybe you could give
him a call and report back with all the juicy details like
availability/lead time, price, etc.?
JF
J
John Fields
Guest
On Mon, 20 Oct 2008 02:16:48 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:
So, since you're drooling over the device, one would think it's
available.
However, a search for Magnatech's home page yields "page not available"
and a search for the part yields nothing in distribution anywhere.
maybe, since you're such good friends with what's-his-face, you could
give him a call and get the juicy details on availability/lead time,
price, etc.?
JF
<rabbitsfriendsandrelations@hotmail.com> wrote:
---John Fields wrote:
On Sun, 19 Oct 2008 18:16:56 +0100, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:
John Fields wrote:
Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
(a) they're not 100 watt - in fact one supplier does a dual die 500W device in
TO-3. With an internal copper heat speader btw.
ONE supplier indeed. How much does that gadget cost?
And how do you get 500 watts out of a TO-3 can? Put it under a fire
hose?
Ask my friend who makes them.
Sorry it's dual die 250W in TO-3 but he does some larger devices too.
It's 500W in SOT227/ISOTOP
http://www.magnatec-uk.com/mosdata.shtml
---
Well, "NEW PRODUCT UNDER DEVELOPMENT" for both the N channel and P
channel devices means it's not available (unless those are old data
sheets.
I've seen plenty of data sheets for devices in volume production that still say
PRELIMINARY on them. So ?
So, since you're drooling over the device, one would think it's
available.
However, a search for Magnatech's home page yields "page not available"
and a search for the part yields nothing in distribution anywhere.
maybe, since you're such good friends with what's-his-face, you could
give him a call and get the juicy details on availability/lead time,
price, etc.?
JF
K
Kevin Aylward
Guest
mrdarrett@gmail.com wrote:
Anyway....
Both have advantages and disadvantages
THD/IMD depends on both the linearity of the intrinsic device (with load)
and how much feedback is applied.
Getting silly distortion figures at silly bandwidths is easier with mosfets,
imo...
Kevin Aylward
www.blonddee.co.uk
www.kevinaylward.co.uk
www.anasoft.co.uk
So...is this a flame or what...?Are there any technical advantages that lateral mosfets have over BJTs
in audio amplifier design?
Do lateral mosfets offer lower theoretical THD+N over the entire audio
spectrum than BJTs for instance?
Thanks,
Michael
Anyway....
Both have advantages and disadvantages
THD/IMD depends on both the linearity of the intrinsic device (with load)
and how much feedback is applied.
Getting silly distortion figures at silly bandwidths is easier with mosfets,
imo...
Kevin Aylward
www.blonddee.co.uk
www.kevinaylward.co.uk
www.anasoft.co.uk
E
Eeyore
Guest
Kevin Aylward wrote:
THD gets confusing at those numbers because you can never remember how many
zeroes there are after the decimal point.
Graham
You're not kidding ! I had < -103dB SINAD back in 1989.Getting silly distortion figures at silly bandwidths is easier with mosfets,
imo...
THD gets confusing at those numbers because you can never remember how many
zeroes there are after the decimal point.
Graham
E
Eeyore
Guest
John Larkin wrote:
kid's stuff.
Graham
No.Eeyore wrote:
John Larkin wrote:
On Fri, 17 Oct 2008 08:27:23 -0700 (PDT), mrdarrett@gmail.com wrote:
Are there any technical advantages that lateral mosfets have over BJTs
in audio amplifier design?
Do lateral mosfets offer lower theoretical THD+N over the entire audio
spectrum than BJTs for instance?
Either needs lots of negative feedback to be really linear, so THD+N
depends on the overall circuit design, not much on the final output
devices.
Maybe for full power but NOT in the vital crossover region.
It's generally easier to drive mosfets than bipolars, but in
audio bandwidths it doesn't matter much. Bipolars, lateral fets,
vertical fets, all can be made to work plenty well enough.
Lateral fets are vastly better for audio. Not least because they match
brilliantly to name another of their features.
I use vertical (conventional power) fets in my NMR gradient amps,
because they are easy to drive fast (directly from a small opamp) and
are (at least some of them are) tough... no second breakdown, easier
to keep biased over temperature.
Also laterals are only made in small quantities and cost a lot.
More audio cargo-cult science.
Matching verticals is a PIG. Laterals do it naturally. Plus biasing them isBipolars, lateral fets, vertical fets,
all will work as well at audio frequencies if the circuit design is
right. All need negative feedback and sensible bias control.
kid's stuff.
Graham
Guest
On Oct 18, 12:13 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
expect it to be better. The portable was later still. The Portable One
has an HP 8903 emulation mode, so I guess you call that clumsy
mode. ;-) Anyway, the HP8903 was good for it's time, but time marches
on.
I really don't like PC based black boxes, so the Portable One would be
my choice for an upgrade. The HP 8903 is a back breaker too.
The applications group at AP is great. The system one has this digital
interface on the back. I couldn't quite get it working, called apps,
and the person asked how many people have access to the box. It turns
out the interface was done with simple gates (TTL I think) and often
people blow them up. The bigger the lab, the more likely someone blows
them up and doesn't own up to it. Well, that was the case, but
fortunately the interface chips are in sockets.
I still have my HP 334A. It is the only THD analyzer I've seen with RF
demod. I can't say the box has seen a power cord in a few years, but
you never know.
wrote:
The AP system one came out later than the HP 8903B, so you wouldm...@sushi.com wrote:
Eeyore wrote:
Damon Hill wrote:
Eeyore wrote
I used an Audio Precision System One of course. Even then it was barely
above residual.
I back-calcuclated it to 0.0004% ~ -106 SINAD.
The vexation I experienced with low-level distortion measurements
with the few designs I could measure with a Tektronix set was that
noise predominated the measurements. I'm not an engineer, and
design for low noise to match distortion levels is beyond me...
as is the price of an AP system.
But at such low distortion levels, is it worth it?
Everything is worth it.
What exactly does back-calculate mean?
To do the RMS addition calculation backwards.
I have used the AP system 1. It does quite a few tests automatically,
so I would say it is worth it. The 8903 I got was $250 or $300 (I
don't recall exactly) about 6 years ago. APs were substantially more
at the time.
It was an 8903 I probably used once on one project. Clumsy to use and poorer
residuals than AP. I'd have the AP Portable One any day over that. In fact for
simple bench work I prefer the Portable One over the System One because it's
simple 'press button' stuff, no mice to arse about with and it takes up little
room. No other audio measuring set comes close in terms of performance or
convenience.
Graham
expect it to be better. The portable was later still. The Portable One
has an HP 8903 emulation mode, so I guess you call that clumsy
mode. ;-) Anyway, the HP8903 was good for it's time, but time marches
on.
I really don't like PC based black boxes, so the Portable One would be
my choice for an upgrade. The HP 8903 is a back breaker too.
The applications group at AP is great. The system one has this digital
interface on the back. I couldn't quite get it working, called apps,
and the person asked how many people have access to the box. It turns
out the interface was done with simple gates (TTL I think) and often
people blow them up. The bigger the lab, the more likely someone blows
them up and doesn't own up to it. Well, that was the case, but
fortunately the interface chips are in sockets.
I still have my HP 334A. It is the only THD analyzer I've seen with RF
demod. I can't say the box has seen a power cord in a few years, but
you never know.