Studio Reference Amplifier

[thimios]

Apex sr 200 studio referance.

cintinua

 

[thimios]

Apex sr 200 studio referance.

All tests as follows
Usys.+/-45v
Cpsu.51.000uf/rail.
out.transistors 2x2sc3264
2x2sa1295
idle current.45ma(25mv on 0.33R)
Vinp. 570mvrms
Vout. 24.6VRMS
Rload 8R

Finaly 3 other photos

1) 1KHz behind zobel
2) 1KHz after zobel
3) 10KHz behind zobel
4) 10KHz after zobel.
5) zero offset.
6)570mv inp ,24v out just pehind cliping

 

[apexaudio]

All tests as follows
Usys.+/-45v
Cpsu.51.000uf/rail.
out.transistors 2x2sc3264
2x2sa1295
idle current.45ma(25mv on 0.33R)
Vinp. 570mvrms
Vout. 24.6VRMS
Rload 8R

Finaly 3 other photos

1) 1KHz behind zobel
2) 1KHz after zobel
3) 10KHz behind zobel
4) 10KHz after zobel.
5) zero offset.
6)570mv inp ,24v out just pehind cliping

Thanks for your work and all this tests.
Regards

 

[thimios]

Thanks for your work and all this tests.
Regards

I should thank you Sr for the fantastic amplifier gave us.
I hope you are always healthy and always with us.
Best regards.
Thimios.
Agrinio Greece.

 

[thimios]

Apex sr 200 studio referance.

I also want to thank everyone who helped in addressing the problem.
Regards.

 

[apexaudio]

I also want to thank everyone who helped in addressing the problem.
Regards.

Thanks to 'alex mm' for pcb design and what is your final circuit?

 

[thimios]

Apex sr 200 studio referance.

Thanks to 'alex mm' for pcb design and what is your final circuit?

Oh I'm literally unpardonable for this my omission
Thank you especially Mr.Alex mm.
Without your's printed circuit board construction would be impossible.
Mr Apex just missed my own question.
This time circuit is with R11=8K2
R18=2K2
added 18pf between collector Q9 base Q2
Theese all modifications.
Is it necessary to keep them all?
Regards.

 

[apexaudio]

Oh I'm literally unpardonable for this my omission
Thank you especially Mr.Alex mm.
Without your's printed circuit board construction would be impossible.
Mr Apex just missed my own question.
This time circuit is with R11=8K2
R18=2K2
added 18pf between collector Q9 base Q2
Theese all modifications.
Is it necessary to keep them all?
Regards.

It's ok and you must use heatsinks for MJE340/350.
Regards

 

[AndrewT]

Thim,
can you post your final schematic? Add notes on what values you changed to reach that success.
And finally what values did not work for your build.

 

[thimios]

sr200 studio refer.

It's ok and you must use heatsinks for MJE340/350.
Regards

I'm on the road for version 3.2 but at this time haven't many parts
Thanks Mr Apex
Thanks Mr Alex mm

 

[thimios]

Thim,
can you post your final schematic? Add notes on what values you changed to reach that success.
And finally what values did not work for your build.

Dear Adrew this is shematic last modified by Apex. Red values are the modifications.
Keep in mind that original schematic is functional also with a little problem an overshot
probably.

 

[wiljj78]

I'm on the road for version 3.2 but at this time haven't many parts
Thanks Mr Apex
Thanks Mr Alex mm

A romantic version of SR200
Good luck!

 

[thimios]

sr200 studio refer.

A romantic version of SR200
Good luck!

Thanks wiljj78

 

[apexaudio]

Very artistic picture of SR200

 

[thimios]

sr200 studio refer.

Very artistic picture of SR200

Just as befits a reference amplifier.
Thanks Mr.

 

[keantoken]

Hi Mr Apex.
I have made a zobel just with i had this time and test again.
first picture is for +/-35v rail 50mv on 0.33r idle current .
out.14vRMS/8R at 11Khz.Please take a look.
Second picture is under same conditions
+/-35v
1 pair 2sc5200/1943
50mv on 0.33
450mv inp./1khz just before start symetrical cliping
19vRMS out/8r
and the draft zobel

For an output zobel, you take the output/speaker leads from directly across the resistor, not the inductor. This is because the resistor needs to have as little series inductance as possible to increase damping at RF. Stray inductance of the inductor leads, as you may have guessed, does not matter. I would use carbon comp for this resistor if possible.

 

[tinitus]

any chance to see a drawing of this

zobel..inductor...I dont understand what you are saying
(zobel cap/resistor is in parallel with output/speaker, and inductor/resistor would be in series)

 

[keantoken]

Here it is.

 

[thimios]

sr200 studio refer.

any chance to see a drawing of this

zobel..inductor...I dont understand what you are saying
(zobel cap/resistor is in parallel with output/speaker, and inductor/resistor would be in series)

Well i did not understand . In your diagrame Zobel is in parallel to the loudspeaker?
As you say non inductive resistors is the must for that circuits but if you haven't ?

 

[keantoken]

It may work either way, but the "non-optimal" approach has a better chance of not working. In any case, I would try the "optimal" way and see if it sounds better.