Building a class A audio amplifier - no audio out

[Eeyore]

stratus46@yahoo.com wrote:

On May 12, 8:27 am, mrdarr...@gmail.com wrote:
On May 12, 12:34 am, stratu...@yahoo.com wrote:
On May 11, 8:00 pm, Jon Kirwan <j...@infinitefactors.org> wrote:
On Mon, 11 May 2009 13:31:51 -0700 (PDT), stratu...@yahoo.com wrote:
Well then perhaps this 'golden oldie' might be of interest.

http://www.swtpc.com/mholley/PopularElectronics/Dec1967/PE_Dec1967.htm

I remember it! There was a follow-up article with another version, as
I recall.

Jon

You probably mean this

http://www.swtpc.com/mholley/PopularElectronics/Jul1969/PE_Jul1969.htm

which I built in high school. It had an annoying tendency to blow the
outputs. And this

http://www.swtpc.com/mholley/PopularElectronics/Oct1970/PE_Oct1970.htm

and another family member

http://www.swtpc.com/mholley/PopularElectronics/Oct1971/PE_Oct_1971_P...

Enough of memory lane for now.

All of those tended to fry your speakers?

Michael

The only units I built were the 2 Tiger amps running right at 60 volts
power supply - I don't remember how far the supply drooped under load,
it was 37 years ago. The finals would blow and take out the power
supply fuse.

Did the output devices have inverse parallel diodes ?

Graham

 

[Michael A. Terrell]

mrdarrett@gmail.com wrote:

On May 12, 9:43 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
mrdarr...@gmail.com wrote:

On May 11, 1:31 pm, stratu...@yahoo.com wrote:
On May 11, 8:30 am, mrdarr...@gmail.com wrote:> On May 11, 8:16 am, stratu...@yahoo.com wrote:

snip
Lots of good stuff here

http://sound.westhost.com/

G˛

Ah, thank you for the reply.

One thing I noticed is, the larger amps on westhost.com (10W+) need
split power supplies (+/-). I'd like to start with something
needing
just 0V-6V or 0V-12V.

Thanks again,

Michael

Well then perhaps this 'golden oldie' might be of interest.

http://www.swtpc.com/mholley/PopularElectronics/Dec1967/PE_Dec1967.htm

G˛

Thanks a bunch!

Michael

"The Brute 70" I built this one in high school. I made my first PC
boards for it. They took the circuit from the RCA Data book and drew up
plans around them. I saw a lot of early commercial solid state PA amps
built from the same basic circuit. Some had been ion daily use for 20
years before they needed repairs. The big change was the addition of a
output transformer to match them to either a 25 or 70 volt line speaker
system.

http://www.swtpc.com/mholley/PopularElectronics/Feb1967/PE_Feb1967.htm

Interesting. Are Q6 and Q7 both supposed to be NPN?

And what is this RCA Data Book?

RCA published a series of transistor dta books throungh the '60s &
'70s. The basic circuit was published right after RCA released the
40411 output transistors used in that circuit. If you take a look, they
run in consecutive type numbers, which indicates they were chosen for
that application. Amps built with the RCA parts were good, for their
time, but the clones often used other transistors and had problems. The
40411 was rated to 100 volts, which was a lot higher than most power
transistors of that time.


--
You can't have a sense of humor, if you have no sense!

 

[Michael A. Terrell]

mrdarrett@gmail.com wrote:

On May 13, 6:09 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
mrdarr...@gmail.com wrote:

On May 12, 9:43 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
mrdarr...@gmail.com wrote:

On May 11, 1:31 pm, stratu...@yahoo.com wrote:
On May 11, 8:30 am, mrdarr...@gmail.com wrote:> On May 11, 8:16 am, stratu...@yahoo.com wrote:

snip
Lots of good stuff here

http://sound.westhost.com/

G˛

Ah, thank you for the reply.

One thing I noticed is, the larger amps on westhost.com (10W+) need
split power supplies (+/-). I'd like to start with something
needing
just 0V-6V or 0V-12V.

Thanks again,

Michael

Well then perhaps this 'golden oldie' might be of interest.

http://www.swtpc.com/mholley/PopularElectronics/Dec1967/PE_Dec1967.htm

G˛

Thanks a bunch!

Michael

"The Brute 70" I built this one in high school. I made my first PC
boards for it. They took the circuit from the RCA Data book and drew up
plans around them. I saw a lot of early commercial solid state PA amps
built from the same basic circuit. Some had been ion daily use for 20
years before they needed repairs. The big change was the addition of a
output transformer to match them to either a 25 or 70 volt line speaker
system.

http://www.swtpc.com/mholley/PopularElectronics/Feb1967/PE_Feb1967.htm

Interesting. Are Q6 and Q7 both supposed to be NPN?

And what is this RCA Data Book?

RCA published a series of transistor dta books throungh the '60s &
'70s. The basic circuit was published right after RCA released the
40411 output transistors used in that circuit. If you take a look, they
run in consecutive type numbers, which indicates they were chosen for
that application. Amps built with the RCA parts were good, for their
time, but the clones often used other transistors and had problems. The
40411 was rated to 100 volts, which was a lot higher than most power
transistors of that time.

--
You can't have a sense of humor, if you have no sense!

Well in lieu of having that nice data book, the free online patent
literature gives this, among others:

http://www.google.com/patents?id=yus8AAAAEBAJ

from
http://www.google.com/patents?lr=&q=audio+and+amplifier+inassignee:rca&scoring=2&sa=N&start=30

All of those are dated in the '70s, and are newer that the data I was
looking for, for you.

Thanks,

Michael

I couldn't find any of my oldest RCA books, or I would have scanned
the ap note for you.

I see a copy of SC11 for sale near here on ABE Books, but it is too
old. It first appeared in SC12 or SC13.

It is about a half hour drive from here, and near a flea market i
haven't been to in almost 10 years. The store wants $5 for it, plus
local tax.


--
You can't have a sense of humor, if you have no sense!

 

On May 13, 6:09 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

mrdarr...@gmail.com wrote:

On May 12, 9:43 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
mrdarr...@gmail.com wrote:

On May 11, 1:31 pm, stratu...@yahoo.com wrote:
On May 11, 8:30 am, mrdarr...@gmail.com wrote:> On May 11, 8:16 am, stratu...@yahoo.com wrote:

snip
 > > Lots of good stuff here

 > >http://sound.westhost.com/

 > > G˛

 > Ah, thank you for the reply.

 > One thing I noticed is, the larger amps on westhost.com (10W+) need
 > split power supplies (+/-).  I'd like to start with something
needing
 > just 0V-6V or 0V-12V.

 > Thanks again,

 > Michael

Well then perhaps this 'golden oldie' might be of interest.

http://www.swtpc.com/mholley/PopularElectronics/Dec1967/PE_Dec1967..htm

G˛

Thanks a bunch!

Michael

   "The Brute 70" I built this one in high school.  I made my first PC
boards for it.  They took the circuit from the RCA Data book and drew up
plans around them.  I saw a lot of early commercial solid state PA amps
built from the same basic circuit.  Some had been ion daily use for 20
years before they needed repairs.  The big change was the addition of a
output transformer to match them to either a 25 or 70 volt line speaker
system.

http://www.swtpc.com/mholley/PopularElectronics/Feb1967/PE_Feb1967.htm

Interesting.  Are Q6 and Q7 both supposed to be NPN?

And what is this RCA Data Book?

   RCA published a series of transistor dta books throungh the '60s &
'70s.  The basic circuit was published right after RCA released the
40411 output transistors used in that circuit.  If you take a look, they
run in consecutive type numbers, which indicates they were chosen for
that application.  Amps built with the RCA parts were good, for their
time, but the clones often used other transistors and had problems.  The
40411 was rated to 100 volts, which was a lot higher than most power
transistors of that time.

--
You can't have a sense of humor, if you have no sense!

Well in lieu of having that nice data book, the free online patent
literature gives this, among others:

http://www.google.com/patents?id=yus8AAAAEBAJ

from
http://www.google.com/patents?lr=&q=audio+and+amplifier+inassignee:rca&scoring=2&sa=N&start=30

Thanks,

Michael

 

On May 13, 9:45 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

mrdarr...@gmail.com wrote:

On May 13, 6:09 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
mrdarr...@gmail.com wrote:

On May 12, 9:43 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
mrdarr...@gmail.com wrote:

On May 11, 1:31 pm, stratu...@yahoo.com wrote:
On May 11, 8:30 am, mrdarr...@gmail.com wrote:> On May 11, 8:16 am, stratu...@yahoo.com wrote:

snip
 > > Lots of good stuff here

 > >http://sound.westhost.com/

 > > G˛

 > Ah, thank you for the reply.

 > One thing I noticed is, the larger amps on westhost.com (10W+) need
 > split power supplies (+/-).  I'd like to start with something
needing
 > just 0V-6V or 0V-12V.

 > Thanks again,

 > Michael

Well then perhaps this 'golden oldie' might be of interest.

http://www.swtpc.com/mholley/PopularElectronics/Dec1967/PE_Dec1967.htm

G˛

Thanks a bunch!

Michael

   "The Brute 70" I built this one in high school.  I made my first PC
boards for it.  They took the circuit from the RCA Data book and drew up
plans around them.  I saw a lot of early commercial solid state PA amps
built from the same basic circuit.  Some had been ion daily use for 20
years before they needed repairs.  The big change was the addition of a
output transformer to match them to either a 25 or 70 volt line speaker
system.

http://www.swtpc.com/mholley/PopularElectronics/Feb1967/PE_Feb1967..htm

Interesting.  Are Q6 and Q7 both supposed to be NPN?

And what is this RCA Data Book?

   RCA published a series of transistor dta books throungh the '60s &
'70s.  The basic circuit was published right after RCA released the
40411 output transistors used in that circuit.  If you take a look, they
run in consecutive type numbers, which indicates they were chosen for
that application.  Amps built with the RCA parts were good, for their
time, but the clones often used other transistors and had problems.  The
40411 was rated to 100 volts, which was a lot higher than most power
transistors of that time.

--
You can't have a sense of humor, if you have no sense!

Well in lieu of having that nice data book, the free online patent
literature gives this, among others:

http://www.google.com/patents?id=yus8AAAAEBAJ

from
http://www.google.com/patents?lr=&q=audio+and+amplifier+inassignee:rc...

   All of those are dated in the '70s, and are newer that the data I was
looking for, for you.

Thanks,

Michael

   I couldn't find any of my oldest RCA books, or I would have scanned
the ap note for you.

   I see a copy of SC11 for sale near here on ABE Books, but it is too
old.  It first appeared in SC12 or SC13.

   It is about a half hour drive from here, and near a flea market i
haven't been to in almost 10 years.  The store wants $5 for it, plus
local tax.

--
You can't have a sense of humor, if you have no sense!

Ah ok, I appreciate the efforts you are going to, to locate the
article. Thank you. But please don't trouble yourself driving to
search for the book on my behalf. I wouldn't want to inconvenience
you.

I was hoping to find something online by searching the Google patent
literature with "RCA" as the assignee. And it may even be possible
that my dad may have the data book, or a similar one. It's just not
very often that I get to see him.

Thanks,

Michael

 

[Eeyore]

"Michael A. Terrell" wrote:

mrdarrett@gmail.com wrote:

And what is this RCA Data Book?

RCA published a series of transistor dta books throungh the '60s &
'70s. The basic circuit was published right after RCA released the
40411 output transistors used in that circuit. If you take a look, they
run in consecutive type numbers, which indicates they were chosen for
that application. Amps built with the RCA parts were good, for their
time, but the clones often used other transistors and had problems. The
40411 was rated to 100 volts, which was a lot higher than most power
transistors of that time.

True but shortly therafter RCA offered the 140V 2N3773 which with 4 devices could deliver ~ 200W into 8
ohms with a decently regulated supply.

That device ruled the roost for a long time.

Modern Toshiba ( and other ) audio output semis got to 230V or so. I well recall designing my first amp
with +/- 100V main rails.

Graham

 

[Eeyore]

mrdarrett@gmail.com wrote:

Well in lieu of having that nice data book, the free online patent
literature gives this, among others:

http://www.google.com/patents?id=yus8AAAAEBAJ

from
http://www.google.com/patents?lr=&q=audio+and+amplifier+inassignee:rca&scoring=2&sa=N&start=30

Not terribly helpful I'm afraid.

Had I read Win's book ( The Art of Electronics ) I might recommend it. I have no idea if it has a specialist
audio section though ( hint Win ).

Graham

 

[Eeyore]

mrdarrett@gmail.com wrote:

On May 13, 9:45 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:

I couldn't find any of my oldest RCA books, or I would have scanned
the ap note for you.

I see a copy of SC11 for sale near here on ABE Books, but it is too
old. It first appeared in SC12 or SC13.

It is about a half hour drive from here, and near a flea market i
haven't been to in almost 10 years. The store wants $5 for it, plus
local tax.

Ah ok, I appreciate the efforts you are going to, to locate the
article. Thank you. But please don't trouble yourself driving to
search for the book on my behalf. I wouldn't want to inconvenience
you.

I was hoping to find something online by searching the Google patent
literature with "RCA" as the assignee. And it may even be possible
that my dad may have the data book, or a similar one. It's just not
very often that I get to see him.

Mulling over old designs has its interest in some ways but you'd do far beter to concentrate on newer technology
that's not impaired by old limitations of device fabrication issues etc.

Go to the Doug Self site for example.

Graham

 

[Michael A. Terrell]

mrdarrett@gmail.com wrote:

Michael A. Terrell wrote:

I couldn't find any of my oldest RCA books, or I would have scanned
the ap note for you.

I see a copy of SC11 for sale near here on ABE Books, but it is too
old. It first appeared in SC12 or SC13.

It is about a half hour drive from here, and near a flea market i
haven't been to in almost 10 years. The store wants $5 for it, plus
local tax.

Ah ok, I appreciate the efforts you are going to, to locate the
article. Thank you. But please don't trouble yourself driving to
search for the book on my behalf. I wouldn't want to inconvenience
you.

I was hoping to find something online by searching the Google patent
literature with "RCA" as the assignee. And it may even be possible
that my dad may have the data book, or a similar one. It's just not
very often that I get to see him.

I drove down there this morning, to visit the flea market and ran
into a couple friends I hadn''t seen in ten years. The book store was a
couple miles further south, but they told me anything listed on Abe
books was kept at a separate location. It turned out ok, I found 20 old
science fiction books for my collection. It was a rough drive, but well
worth the trip.

I didn't know they were doing controlled burns in the forest, so
there was a lot of thick smoke in some places.


--
You can't have a sense of humor, if you have no sense!