Unusual amp from 1987

[minek123]

I have a PCB in sprint layout that I can share if you want some inspiration 🙂

 

[egra]

I have a PCB in sprint layout that I can share if you want some inspiration 🙂

OK, Thank you. 🙂

 

[minek123]

Priv msg sent

 

[stanislav1957]

I have a symmetrical version of the PCB . Sketch. I can share

 

[minek123]

In Sprint Layout software? If yes, I'm interested.

 

[stanislav1957]

I'll check it out and throw it in the sprint.Meanwhile, the drawing.
With overload protection

 

[minek123]

Thanks Maxim.
How this GROUND PLANE pcbs worked for you in the past?
Is it a good thing?

 

[stanislav1957]

I didn't make a symmetrical version. Preparing the PCB for the order

 

[egra]

I have a symmetrical version of the PCB . Sketch. I can share

Thank you Maxim. First I want to build the low power version of quasi hexfet and if it really sounds as clear as Korvet amps i will try the higher power version as well. On a Russian site I found a great version of the "УМЗЧ" amplifier with impressive sound and specifications:

- THD at 20 kHz: 0.001% (150 W/8 Ohms)
- Bandwith (-3 dB): 0 - 800000 Hz
- Slew Rate: 100 V/μs
- S/N: 120 dB

What we want more? Unfortunately this project seems a bit complicated for me.

 

[egra]

I didn't make a symmetrical version. Preparing the PCB for the order

What "symmetrical version" means?

 

[egra]

Looks very good, Maxim.

 

[stanislav1957]

Sounds great.Yes, they all sound great in this complexity.But I'm not interested in him.I have my own monster

 

[minek123]

"УМЗЧ" - audio frequency power amplifier.
General name of amplifiers in Russian
I guess its name is "BBC-2011"

For symmetrical amp ideas see posts #188, #190

 

[stanislav1957]

What "symmetrical version" means?

 

[egra]

Oh, I see. Both CCS' in VAS are controlled.

 

[stanislav1957]

symmetry is beautiful

 

[stanislav1957]

Thank you Maxim.

What we want more? Unfortunately this project seems a bit complicated for me.

one oramp integrator controls the DC voltage level at the output of the amplifier, the second oramp eliminates the influence of acoustic wires.
the rest has already been dealt with

 

[minek123]

capacitanc7 should be increased. 22PF
It is necessary to select it.
C12/c13 can also be increased

( It looks much better with 100 Ohms (In original Wiederhold it is 1k)]750ом УМЗЧ ВВ и СЛА

Maxim, which exactly capacitors in which schematic did you mean?

There is still a slight problem with clipping behavior at 1.7V.
I don't think it's really critical, but maybe it can be solved somehow?

 

[stanislav1957]

capacitanc7 should be increased. 22PF
It is necessary to select it.
C12/c13 can also be increased

It was about LP / Lomakin/The Parshin. C7/C12/С13

Цитата:
( It looks much better with 100 Ohms (In original Wiederhold it is 1k)]750ом УМЗЧ ВВ и СЛА

This is correction in the ancient Wiederhold /

Я не думаю, что это действительно критично

Not critical. It doesn't affect your work

 

[minek123]

Thanks for clarification!