Tietze & Schenk BA-50M PCB
After several weeks (?) of production time, the boards have finally arrived today. No one recommends using VFETs without source resistors, even for single par. Unless I would use an 'auto-bias' circuit. So I'm trying to place the transdiode sensor as efficiently as possible. I will glue it on FET direclty as follows. Glued on heat sink it would not be efficient and fast enough for this, I guess.
This is a "HexFet Amp Based on Philips AH578 and LMK" with 36V supply voltage and single pair FET output. The nickname is Tietze & Schenk BA-50M. The topology was first published in mid 70's by Dr. Tietze and Dr. Schenk as "Breitband Verstärker" i.e. Broadband amplifier (BA), 50W (50), the circuit designed by minek123 (M). Later, I will refer to it so.
After several weeks (?) of production time, the boards have finally arrived today. No one recommends using VFETs without source resistors, even for single par. Unless I would use an 'auto-bias' circuit. So I'm trying to place the transdiode sensor as efficiently as possible. I will glue it on FET direclty as follows. Glued on heat sink it would not be efficient and fast enough for this, I guess.
This is a "HexFet Amp Based on Philips AH578 and LMK" with 36V supply voltage and single pair FET output. The nickname is Tietze & Schenk BA-50M. The topology was first published in mid 70's by Dr. Tietze and Dr. Schenk as "Breitband Verstärker" i.e. Broadband amplifier (BA), 50W (50), the circuit designed by minek123 (M). Later, I will refer to it so.
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Interesting observation - I just built a new PSU for my amps.
I encased 4 pieces of HP laptop switching PSUs (each of them 19.5V, 12A).
Last year, I used similar PSU bricks to power Alpha Nirvana class A amp. It worked great.
GENUINE HP AC ADAPTER 230W HSTNN-DA12 19.5V 11.8A 609946-001 608432-003 | eBay
The PSU box gives me +/- 20V rails and +/- 40V rails.
I tried to play the latest amp I built from this thread, using this new PSU,
and I can ACTUALLY tell the difference in sound. Previous PSU was a linear
PSU with a toroid transoformer.
With this new PSU, when listening to music (flac) ripped from 80's vinyl record
('Fuerza Major' by Camaro's Gang) I can actually hear subtle vinyl scratches,
that I didn't even know were there!
Also, but I'm less sure about this - the bass might be slightly stronger.
Photo - Amp sitting on top of the new PSU.
I encased 4 pieces of HP laptop switching PSUs (each of them 19.5V, 12A).
Last year, I used similar PSU bricks to power Alpha Nirvana class A amp. It worked great.
GENUINE HP AC ADAPTER 230W HSTNN-DA12 19.5V 11.8A 609946-001 608432-003 | eBay
The PSU box gives me +/- 20V rails and +/- 40V rails.
I tried to play the latest amp I built from this thread, using this new PSU,
and I can ACTUALLY tell the difference in sound. Previous PSU was a linear
PSU with a toroid transoformer.
With this new PSU, when listening to music (flac) ripped from 80's vinyl record
('Fuerza Major' by Camaro's Gang) I can actually hear subtle vinyl scratches,
that I didn't even know were there!
Also, but I'm less sure about this - the bass might be slightly stronger.
Photo - Amp sitting on top of the new PSU.
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>Will try to post the relevant page later if it is of any interest. |
It was posted already in another thread:
Unusual amp from 1987
Maybe you have more/different source info about this topology?
As far as I know it was first published by Faran and Fulks.
See this post:
Unusual amp from 1987
It was posted already in another thread:
Unusual amp from 1987
Maybe you have more/different source info about this topology?
As far as I know it was first published by Faran and Fulks.
See this post:
Unusual amp from 1987
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I have to correct what I wrote. This schematic what I refer to can only be found in a later edition of the book (1992?). I have a printed version of the first edition from 70's translated in Hungarian. In this book you can find a single ended (earlier) version of T-S broadband amplifier only. It's similar to LMK, but in this case the emitter current of the first transistor is equal to the output current of the opamp (5-7mA), so this circuit is much more sensitive to the type of IC used.
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I don't have the book in my hand right now, but those could be overcurrent protection diodes.