Hilarious

J

Jim Thompson

Guest
Stumbled onto the following URL...

http://semiconductormuseum.com/ConstructionProjects/ConstructionProjects_Penfield_MiniAmp.htm

This is personally hilarious to me since Paul Penfield was one of my
(very excellent) instructors at MIT... but he taught field theory at
the time... I didn't know he had dabbled in audio.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"Jim Thompson" <thegreatone@example.com> wrote in message
news:5ht0d09gtmf4npn50qno50u2jrr087ah66@4ax.com...
Stumbled onto the following URL...


http://semiconductormuseum.com/ConstructionProjects/ConstructionProjects_Penfield_MiniAmp.htm

This is personally hilarious to me since Paul Penfield was one of my
(very excellent) instructors at MIT... but he taught field theory at
the time... I didn't know he had dabbled in audio.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim,
Click to expand...
Genuinely odd. I have never seen an amp of that era before that did not use
a transformer coupled speaker. Wonder if these speakers were originally
special built to handle the DC, and also higher impedance. 40 Ohms comes to
mind. I notice the volume control is connected in a conventional manner;
didn't they use to turn it around because of the relatively low base input
impedance?

I have a 1962 Lafayette Electronics catalog. Sometimes fun to look at.

B&G Merlot, 2002. 1.5L for 10.99

Tam
 
On Wed, 16 Jun 2004 14:07:46 -0400, "Tam/WB2TT"
<t-tammaru@c0mca$t.net> wrote:

"Jim Thompson" <thegreatone@example.com> wrote in message
news:5ht0d09gtmf4npn50qno50u2jrr087ah66@4ax.com...
Stumbled onto the following URL...


http://semiconductormuseum.com/ConstructionProjects/ConstructionProjects_Penfield_MiniAmp.htm

This is personally hilarious to me since Paul Penfield was one of my
(very excellent) instructors at MIT... but he taught field theory at
the time... I didn't know he had dabbled in audio.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim,
Genuinely odd. I have never seen an amp of that era before that did not use
a transformer coupled speaker. Wonder if these speakers were originally
special built to handle the DC, and also higher impedance. 40 Ohms comes to
mind. I notice the volume control is connected in a conventional manner;
didn't they use to turn it around because of the relatively low base input
impedance?

I have a 1962 Lafayette Electronics catalog. Sometimes fun to look at.

B&G Merlot, 2002. 1.5L for 10.99

Tam
Click to expand...
Back then I built a class-A amplifier for my '61 Renault Dauphine
using one of those Delco door-knob Ge power devices. I used a choke
load and capacitively coupled to the speaker. Actually sounded pretty
decent.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Wed, 16 Jun 2004 12:55:33 -0700, the renowned Jim Thompson
<thegreatone@example.com> wrote:
Back then I built a class-A amplifier for my '61 Renault Dauphine
using one of those Delco door-knob Ge power devices. I used a choke
load and capacitively coupled to the speaker. Actually sounded pretty
decent.

...Jim Thompson
Click to expand...
I'd almost forgotten those power transistor things. Kind of an
inverted stud package. Probably a better thermal design of package
than 99% of what's in use these days.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
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On a sunny day (Wed, 16 Jun 2004 14:07:46 -0400) it happened "Tam/WB2TT"
<t-tammaru@c0mca$t.net> wrote in <XMSdnX3EhurvEU3dRVn-vA@comcast.com>:
Jim,
Genuinely odd. I have never seen an amp of that era before that did not use
a transformer coupled speaker.
High Ohm or speakers have been used here.
Click to expand...
A bit later in the beginning of the sixties there even was a kit here
you could buy with an amp that looked a lot like that.


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On Wed, 16 Jun 2004 20:04:52 GMT, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

On Wed, 16 Jun 2004 12:55:33 -0700, the renowned Jim Thompson
thegreatone@example.com> wrote:

Back then I built a class-A amplifier for my '61 Renault Dauphine
using one of those Delco door-knob Ge power devices. I used a choke
load and capacitively coupled to the speaker. Actually sounded pretty
decent.

...Jim Thompson

I'd almost forgotten those power transistor things. Kind of an
inverted stud package. Probably a better thermal design of package
than 99% of what's in use these days.

Best regards,
Spehro Pefhany
Click to expand...
Yep, even had a guide pin to keep them from rotating while torquing
them up.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
Jim Thompson wrote:
On Wed, 16 Jun 2004 20:04:52 GMT, Spehro Pefhany
speffSNIP@interlogDOTyou.knowwhat> wrote:


On Wed, 16 Jun 2004 12:55:33 -0700, the renowned Jim Thompson
thegreatone@example.com> wrote:

Back then I built a class-A amplifier for my '61 Renault Dauphine
using one of those Delco door-knob Ge power devices. I used a choke
load and capacitively coupled to the speaker. Actually sounded pretty
decent.

...Jim Thompson

I'd almost forgotten those power transistor things. Kind of an
inverted stud package. Probably a better thermal design of package
than 99% of what's in use these days.

Best regards,
Spehro Pefhany


Yep, even had a guide pin to keep them from rotating while torquing
them up.

...Jim Thompson
Click to expand...
I was just digging through my box today,and found a ECG105 germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)
 
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On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened ptaylor
<ptaylor@qwest.net> wrote in <5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105 germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)
Click to expand...
If you have only one, class A hehehehe.


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"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
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On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened ptaylor
ptaylor@qwest.net> wrote in <5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105 germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP and Si
Click to expand...
NPN.

Tam
 
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:7fidnbOvzoClpE7dRVn-sQ@comcast.com...
"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
**** Post for FREE via your newsreader at post.usenet.com ****

On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened ptaylor
ptaylor@qwest.net> wrote in <5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105 germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP and Si
NPN.
Click to expand...
What did they do before Si? Create a Class A headache? ;->
 
"Norm Dresner" <ndrez@att.net> wrote in message
news:mgHAc.91891$Gx4.53715@bgtnsc04-news.ops.worldnet.att.net...
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:7fidnbOvzoClpE7dRVn-sQ@comcast.com...

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
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On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened ptaylor
ptaylor@qwest.net> wrote in <5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105 germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP and
Si
NPN.

What did they do before Si? Create a Class A headache? ;-

I have a 1969 RCA Transistor Manual. It shows some transformer coupled audio
Click to expand...
amplifiers. Unfortunately, the manual is too recent, because it already has
silicon power transistors in it. Wish I had the old GE manual. That
contained vintage stuff. I seem to recall somebody did have an all PNP push
pull direct coupled amplifier (no NPN EF); that would have been the
predecessor to the quasi complementary.

Tam
 
On Fri, 18 Jun 2004 16:23:00 -0400, "Tam/WB2TT"
<t-tammaru@c0mca$t.net> wrote:

"Norm Dresner" <ndrez@att.net> wrote in message
news:mgHAc.91891$Gx4.53715@bgtnsc04-news.ops.worldnet.att.net...
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:7fidnbOvzoClpE7dRVn-sQ@comcast.com...

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
**** Post for FREE via your newsreader at post.usenet.com ****

On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened ptaylor
ptaylor@qwest.net> wrote in <5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105 germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP and
Si
NPN.

What did they do before Si? Create a Class A headache? ;-

I have a 1969 RCA Transistor Manual. It shows some transformer coupled audio
amplifiers. Unfortunately, the manual is too recent, because it already has
silicon power transistors in it. Wish I had the old GE manual. That
contained vintage stuff. I seem to recall somebody did have an all PNP push
pull direct coupled amplifier (no NPN EF); that would have been the
predecessor to the quasi complementary.

Tam
Click to expand...
I have the 1964 "GE Transistor Manual". It shows some output stages
using both an output transformer and a driver transformer. But it
also shows some totem pole outputs using all PNPs, but with some
small-signal NPNs in the signal path.

The only old RCA manuals I have are either CMOS or tooobz ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"Jim Thompson" <thegreatone@example.com> wrote in message
news:74m6d05622qf9arfiicgp98g831e4jm5m5@4ax.com...
On Fri, 18 Jun 2004 16:23:00 -0400, "Tam/WB2TT"
t-tammaru@c0mca$t.net> wrote:


"Norm Dresner" <ndrez@att.net> wrote in message
news:mgHAc.91891$Gx4.53715@bgtnsc04-news.ops.worldnet.att.net...
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:7fidnbOvzoClpE7dRVn-sQ@comcast.com...

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
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On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened
ptaylor
ptaylor@qwest.net> wrote in <5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105
germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP
and
Si
NPN.

What did they do before Si? Create a Class A headache? ;-

I have a 1969 RCA Transistor Manual. It shows some transformer coupled
audio
amplifiers. Unfortunately, the manual is too recent, because it already
has
silicon power transistors in it. Wish I had the old GE manual. That
contained vintage stuff. I seem to recall somebody did have an all PNP
push
pull direct coupled amplifier (no NPN EF); that would have been the
predecessor to the quasi complementary.

Tam


I have the 1964 "GE Transistor Manual". It shows some output stages
using both an output transformer and a driver transformer. But it
also shows some totem pole outputs using all PNPs, but with some
small-signal NPNs in the signal path.

The only old RCA manuals I have are either CMOS or tooobz ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Just for kicks I ran SWCAD on an all PNP output stage. It does work. Without
Click to expand...
much thought to biasing, I was getting about 18V p-p into 10 Ohms from
a -24V supply. Requires a diode in the collector circuit of the ce half. I
saw no obvious crossover distortion.

Tam
 
Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote in message news:<40d0a89c@post.usenet.com>...
On a sunny day (Wed, 16 Jun 2004 14:07:46 -0400) it happened "Tam/WB2TT"
t-tammaru@c0mca$t.net> wrote in <XMSdnX3EhurvEU3dRVn-vA@comcast.com>:

Jim,
Genuinely odd. I have never seen an amp of that era before that did not use
a transformer coupled speaker.
High Ohm or speakers have been used here.
A bit later in the beginning of the sixties there even was a kit here
you could buy with an amp that looked a lot like that.
Click to expand...

Before my time but I would have expected to see transformers at every
turn, considering the high price of trs then. Well, either that or
valves - somewhere I've got an oldie proudly badged as 'transistor',
and yes, it contains 4 or 5 valves.

I would go for a quite different germanium design myself though. Class
B output pair driven by an LM324, nothing else, no biasing. Works very
nicely. People always think it will distort badly but it doesnt. Took
me a bit of thinking to figure out why.


Regards, NT
 
Can you scan the circuit. I'm very curious to see how it's done.

Thanks
Norm

"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:2dCdnc_3tOmA_U7dRVn-vw@comcast.com...
"Jim Thompson" <thegreatone@example.com> wrote in message
news:74m6d05622qf9arfiicgp98g831e4jm5m5@4ax.com...
On Fri, 18 Jun 2004 16:23:00 -0400, "Tam/WB2TT"
t-tammaru@c0mca$t.net> wrote:


"Norm Dresner" <ndrez@att.net> wrote in message
news:mgHAc.91891$Gx4.53715@bgtnsc04-news.ops.worldnet.att.net...
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:7fidnbOvzoClpE7dRVn-sQ@comcast.com...

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
**** Post for FREE via your newsreader at post.usenet.com ****

On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened
ptaylor
ptaylor@qwest.net> wrote in
5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105
germanium
transistor.. (100W PNP audio output) I'm sure theres more in
that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP
and
Si
NPN.

What did they do before Si? Create a Class A headache? ;-

I have a 1969 RCA Transistor Manual. It shows some transformer coupled
audio
amplifiers. Unfortunately, the manual is too recent, because it already
has
silicon power transistors in it. Wish I had the old GE manual. That
contained vintage stuff. I seem to recall somebody did have an all PNP
push
pull direct coupled amplifier (no NPN EF); that would have been the
predecessor to the quasi complementary.

Tam


I have the 1964 "GE Transistor Manual". It shows some output stages
using both an output transformer and a driver transformer. But it
also shows some totem pole outputs using all PNPs, but with some
small-signal NPNs in the signal path.

The only old RCA manuals I have are either CMOS or tooobz ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Just for kicks I ran SWCAD on an all PNP output stage. It does work.
Without
much thought to biasing, I was getting about 18V p-p into 10 Ohms from
a -24V supply. Requires a diode in the collector circuit of the ce half. I
saw no obvious crossover distortion.

Tam
Click to expand...
 
"Jim Thompson" <thegreatone@example.com> wrote in message
news:t091d0d94q08qog9knfqf2f9d4ev0hml85@4ax.com...
On Wed, 16 Jun 2004 14:07:46 -0400, "Tam/WB2TT"
t-tammaru@c0mca$t.net> wrote:


"Jim Thompson" <thegreatone@example.com> wrote in message
news:5ht0d09gtmf4npn50qno50u2jrr087ah66@4ax.com...
Stumbled onto the following URL...



http://semiconductormuseum.com/ConstructionProjects/ConstructionProject
s_Penfield_MiniAmp.htm

This is personally hilarious to me since Paul Penfield was one of
my
(very excellent) instructors at MIT... but he taught field theory
at
the time... I didn't know he had dabbled in audio.

...Jim Thompson


Jim,
Genuinely odd. I have never seen an amp of that era before that did
not use
a transformer coupled speaker. Wonder if these speakers were
originally
special built to handle the DC, and also higher impedance. 40 Ohms
comes to
mind. I notice the volume control is connected in a conventional
manner;
didn't they use to turn it around because of the relatively low base
input
impedance?

I have a 1962 Lafayette Electronics catalog. Sometimes fun to look
at.

B&G Merlot, 2002. 1.5L for 10.99

Tam


Back then I built a class-A amplifier for my '61 Renault Dauphine
using one of those Delco door-knob Ge power devices. I used a choke
load and capacitively coupled to the speaker. Actually sounded pretty
decent.

...Jim Thompson
--
Click to expand...
Back in high school, I knew a guy who had a Renault Dauphine and he was
6 foot 8. I could never figure that out. Today most people wouldn't be
caught dead with a French car. Next to the Yugo...

The Delco 2N278 TO-36 on a big heatsink, and a big choke were standard
on the back of those GM radios of those years. I replaced quite a few
of those transistors, got a lot of white silicone goop on my hands.
Screwed up an occasional mica washer, too.

I hated to work on Caddy radios because of all the air conditioning
ducts that were in the way. Since it was a class A circuit, with heavy
collector current, the germanium trtansistors tended to get out of hand
when the environment get hot. Did you notice in the schematic in the
URL above, that the DC was also across the headphones? I don't think
I'd like to have DC thru a pair of headphones, they might singe my ears!
Someone should've put a 1000 uF cap in series with the headphone jack.
 
"Jim Thompson" <thegreatone@example.com> wrote in message
news:foa1d0pmvgae3qtbq05seng56nkk9rq8m6@4ax.com...
On Wed, 16 Jun 2004 20:04:52 GMT, Spehro Pefhany
speffSNIP@interlogDOTyou.knowwhat> wrote:

On Wed, 16 Jun 2004 12:55:33 -0700, the renowned Jim Thompson
thegreatone@example.com> wrote:

Back then I built a class-A amplifier for my '61 Renault Dauphine
using one of those Delco door-knob Ge power devices. I used a choke
load and capacitively coupled to the speaker. Actually sounded
pretty
decent.

...Jim Thompson

I'd almost forgotten those power transistor things. Kind of an
inverted stud package. Probably a better thermal design of package
than 99% of what's in use these days.

Best regards,
Spehro Pefhany

Yep, even had a guide pin to keep them from rotating while torquing
them up.

...Jim Thompson
--
Click to expand...
I've got an interesting story about one of those TO-36 transistors.
There was an old guy who lived in a trailer park who kept bugging my ham
buddy and I about building a circuit for him. He was half-baked, said
he wanted a metal detector circuit that would work at a certain
frequency, so he could find gold in the soil. He said that he needed a
transistor that would do so and so frequency, and he was trying to get
one from the electronics store. The guys at the store pulled a joke on
him, gave him a Motorola 2N278 that was all gold plated, so it looked
really cool. It was a burned out transistor from a car radio, and they
told him that that little stud on the bottom next to the threaded stud
had to go into a hole in a waveguide so it would put out RF.

My ham buddy and I were in high school, and we were always in need of
funding so even tho we knew this guy was a crackpot, we put up with him
to see if we could make some money. Well, he gave us that power
transistor and told us what he needed, and we looked at each other
incredulously, and knew that someone at the store was pulling a joke on
him. But they didn't charge him for the transistor so they weren't
doing anything illegal.

We tested the transistor, and tried to convince the old guy that this
was just a burned out power transistor, and that it wouldn't work as he
thought. But his mind was made up that he could get that transistor to
put out RF into a waveguide. Sorry to burst his bubble. but it was just
a useless, burned out 2N278.
 
"Norm Dresner" <ndrez@att.net> wrote in message
news:t0PAc.4061$OB3.57@bgtnsc05-news.ops.worldnet.att.net...
Can you scan the circuit. I'm very curious to see how it's done.
Click to expand...
Easy enough to explain:

Transistor Q1, emitter to ground, resistor (120 - 330 Ohms) from collector
to -VCC. Base is input.

Transistor Q2, base of Q2 to collector of Q1. Collector of Q2 to -VCC,
emitter is output.

Diode D1, anode to collector of Q1, cathode to emitter of Q2 (output
terminal).

I made no attempt to reduce dead time, but the thing looks OK with unity
feedback doing a transient analysis with 1 KHz sine wave input.

Tam
 
"Norm Dresner" <ndrez@att.net> wrote in message
news:mgHAc.91891$Gx4.53715@bgtnsc04-news.ops.worldnet.att.net...
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
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"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
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On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened
ptaylor
ptaylor@qwest.net> wrote in <5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105
germanium
transistor.. (100W PNP audio output) I'm sure theres more in that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP
and Si
NPN.

What did they do before Si? Create a Class A headache? ;-
Click to expand...
There _are_ germanium NPN power transistors. CBS's 2N1296 is one
example (of which I have a few). But the usual was to use two PNP
germanuim power transistors in the standard totem pole circuit, with a
PNP and an NPN for the drivers.

I have an old amp that used germanium output transistors, and some
clueless tech tried to use silicons. It turned into a transmitter,
putting out above the AM broadcast band.
 
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:pLOdnTnWovK90k7dRVn-hw@comcast.com...
"Norm Dresner" <ndrez@att.net> wrote in message
news:mgHAc.91891$Gx4.53715@bgtnsc04-news.ops.worldnet.att.net...
"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message
news:7fidnbOvzoClpE7dRVn-sQ@comcast.com...

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:40d312ef@post.usenet.com...
**** Post for FREE via your newsreader at post.usenet.com ****

On a sunny day (Thu, 17 Jun 2004 14:01:32 -0700) it happened
ptaylor
ptaylor@qwest.net> wrote in
5FnAc.38$UG5.76348@news.uswest.net>:

I was just digging through my box today,and found a ECG105
germanium
transistor.. (100W PNP audio output) I'm sure theres more in
that
box,somewhere..

Anybody know of any suitable schematics? ;-)

If you have only one, class A hehehehe.
They used to build complementary symmetry audio amps with a Ge PNP
and
Si
NPN.

What did they do before Si? Create a Class A headache? ;-

I have a 1969 RCA Transistor Manual. It shows some transformer coupled
audio
amplifiers. Unfortunately, the manual is too recent, because it
already has
silicon power transistors in it. Wish I had the old GE manual. That
contained vintage stuff. I seem to recall somebody did have an all PNP
push
pull direct coupled amplifier (no NPN EF); that would have been the
predecessor to the quasi complementary.
Click to expand...
On occasion you can find the GE manuals for auction on Ebay. Going rate
seems to be less than ten bucks includiong shipping. Just keep your
eyes open for them.

> Tam
 
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