Pass bjt cascode amplifier from the 70s or 80s..

GregH2 · 16th August 2011, 11:32 AM

Does anyone know anything about this amplifier? I would love to have some info about it, especially a schematic! Anyone heard it? Listening impressions?

rsdio · 16th August 2011, 12:52 PM

The article is everywhere. Check PassLabs.com, PassDIY.com, FirstWatt.com, ...
Are you looking for information that is not in the article?

buzzforb · 16th August 2011, 01:00 PM

a40 article

GregH2 · 16th August 2011, 01:41 PM

Rsdio,

The cascode article shows a simplified schematic. I want to see the full version, if possible. I am talking about the one that Nelson mentions has been patented. It has a cascaded input, vas and output stage, but the schematic is diagrammatic and does not show the cascode voltages or biasing arrangements.

Buzzforb, the a40 is not a cascode amplifier as far as I can tell.

Any ideas anyone?

Nelson Pass · 16th August 2011, 06:20 PM

The article is about cascode amplifiers.

Pass Diy

select projects

scroll down to 1978, "Cascode Amplifier Design"

The products were the CAS-1 and CAS-2 power amplifiers.

jazz · 16th August 2011, 07:31 PM

Hi,

These are af few schematics posted in the adress below:

THRESHOLD CAS-2 poweramp.

I'd also be interested replacement parts for the transistors used. I've got a case, trannie and some capacitance ready...

regards,
Joris

rsdio · 16th August 2011, 08:05 PM

Quote:

Originally Posted by swordfishy

The cascode article shows a simplified schematic. I want to see the full version, if possible. I am talking about the one that Nelson mentions has been patented. It has a cascaded input, vas and output stage, but the schematic is diagrammatic and does not show the cascode voltages or biasing arrangements.

Have you grabbed the patent documents?

GregH2 · 17th August 2011, 12:10 AM

Quote:

Originally Posted by jazz

Hi,

These are af few schematics posted in the adress below:

THRESHOLD CAS-2 poweramp.

I'd also be interested replacement parts for the transistors used. I've got a case, trannie and some capacitance ready...

regards,
Joris

Thanks Jazz, this is what I have been looking for!

Nelson Pass · 17th August 2011, 12:16 AM

Quote:

Originally Posted by rsdio

Have you grabbed the patent documents?

There is no patent of mine referencing the circuit.

It's just the usual ways of cascoding circuits, at this time nothing you
haven't seen before.

Nelson Pass · 17th August 2011, 12:20 AM

Quote:

Originally Posted by jazz

Hi,I'd also be interested replacement parts for the transistors used.

The outputs were 2n5878 and 2n5876, the inputs were 2n6571 and the
rest of the to92 were MPSL01 and MPSL51 if I recall correctly.

16th August 2011, 11:32 AM	#1
GregH2 diyAudio Member Join Date: Oct 2009	Pass bjt cascode amplifier from the 70s or 80s.. Does anyone know anything about this amplifier? I would love to have some info about it, especially a schematic! Anyone heard it? Listening impressions?

16th August 2011, 07:31 PM	#6
jazz diyAudio Member Join Date: Dec 2001 Location: leiden, physically that is...	Hi, These are af few schematics posted in the adress below: THRESHOLD CAS-2 poweramp. I'd also be interested replacement parts for the transistors used. I've got a case, trannie and some capacitance ready... regards, Joris __________________ oh, what a beautifull day I wanna go out and play!

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16th August 2011, 12:52 PM	#2
rsdio diyAudio Member Join Date: Feb 2008 Location: Seattle	The article is everywhere. Check PassLabs.com, PassDIY.com, FirstWatt.com, ... Are you looking for information that is not in the article?

16th August 2011, 01:00 PM	#3
buzzforb diyAudio Member Join Date: Oct 2010 Location: Burlington, NC	a40 article

16th August 2011, 01:41 PM	#4
GregH2 diyAudio Member Join Date: Oct 2009	Rsdio, The cascode article shows a simplified schematic. I want to see the full version, if possible. I am talking about the one that Nelson mentions has been patented. It has a cascaded input, vas and output stage, but the schematic is diagrammatic and does not show the cascode voltages or biasing arrangements. Buzzforb, the a40 is not a cascode amplifier as far as I can tell. Any ideas anyone?

16th August 2011, 06:20 PM	#5
Nelson Pass The one and only Join Date: Mar 2001	The article is about cascode amplifiers. Pass Diy select projects scroll down to 1978, "Cascode Amplifier Design" The products were the CAS-1 and CAS-2 power amplifiers.

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