power supply sulzer-borbely

[maxpou]

hi everybody,
i would like to know the best opamp for ps sulzer-borbely. i have 32v unreg. on vss+ and i want 24v reg. i don't use lm317 because i don't have enough difference voltage between my input and output, i think. thank you!!

[peranders]

I'll guess you have pretty many opamps to choose from and NE5534 is not so bad. You should look for speed around 10-20 V/µs. If you want to choose faster opamps you may check the "super regulator" which has a class driver for the pass transistor.

What are you going to use the regulator for?

[maxpou]

I want only make test in phono preamp, line preamp and my analog circuit cd player because i use 78XX. As i wrote i have 32V. unreg. for PS phono and line preamp but i have 24V. reg for my 2 circuits. My PCB for this PS circuit is already design. I think used the AD817/DIP8. Can i use it this opamp?thank you!!

[peranders]

I think AD817 is a bit too fast but you can always test. In a super regulator it will work very nicely but then the pcb layout is very important.

[jan.didden]

Originally posted by maxpou
I want only make test in phono preamp, line preamp and my analog circuit cd player because i use 78XX. As i wrote i have 32V. unreg. for PS phono and line preamp but i have 24V. reg for my 2 circuits. My PCB for this PS circuit is already design. I think used the AD817/DIP8. Can i use it this opamp?thank you!!

If you supply the opamp from the regulated output voltage rather than the unregulated input voltage, the improvement is more than you can do with any opamp swap - and is basically free.

You really should read the super reg threads.

Jan Didden

[Elso Kwak]

Originally posted by janneman

If you supply the opamp from the regulated output voltage rather than the unregulated input voltage, the improvement is more than you can do with any opamp swap - and is basically free.

You really should read the super reg threads.

Jan Didden

It's no improvement at all IMHO.
All those super-duper high-speed opamps is asking for trouble.

:bs:

[maxpou]

Hi peranders,
can you give me a trick for design my pcb well? thank you

[peranders]

Originally posted by janneman
If you supply the opamp from the regulated output voltage rather than the unregulated input voltage, the improvement is more than you can do with any opamp swap - and is basically free.

You really should read the super reg threads.

The thing is that only some opamps will start if you do that unless you add some "trick", one of them can be found in the mentioned threads.

[peranders]

Originally posted by Elso Kwak
It's no improvement at all IMHO.
All those super-duper high-speed opamps is asking for trouble.

I'll guess you are right for _some_ applications but have you really tried?

[Elso Kwak]

Originally posted by peranders

I'll guess you are right for _some_ applications but have you really tried?

YEP

[maxpou]

what's the voltage drop in LM317?

[Eva]

In that schematic, the LM317 is set up to force the pass transistor to work at a fixed Vce of 1.25*(1000+825)/1000=2.28V. You can imagine it as an "active cascode". Knowing bipolar transistor behaviour at low Vce levels, I don't think that such a low Vce can provide any advantage, 5V would seem more reasonable.

[peranders]

It works pretty fine with the LM317 set at 2.5 volts as I have used (1k+1k).

[Eva]

No doubt that it can work that way, but the lower the Vce, the lower the current level and the frequency above which which hFE starts to roll-off.

[maxpou]

Hi Peranders
is there much better result in the way than you connect the LM317 versus Borbely and what that changes? thank you!!!

[peranders]

I don't know if it's much better but it's rather practical and you don't have to trim the LM317.

[maxpou]

hi, i send you the schematic and pcb with the modification for supply of IC1. please i would to know if it's correct or i can have problem.
IC1:AD817
D1,D2: BY255
C1,C2,C7,C11: WIMA MKP10 .01
C3,C4,C5,C6: NICHICON FW 4700UF
Q1: D44H11
C8,C9: 47UF ELNA CERAFINE
C10: 100UF ELNA CERAFINE
D3,D4: 1N4148
D5: LM329

I TRY LM317 AS JUNG LATER

[maxpou]

here PCB
p.s. excuse me, as preanders too
thank you!!!

[peranders]

I'm afraid your design probably won't work. Have you thought about the startup? At zero volts, how will the opamp work?

[jackinnj]

Originally posted by Elso Kwak



It's no improvement at all IMHO.
All those super-duper high-speed opamps is asking for trouble.

:bs:

That fateful phrase from Audio Amateur "It oscillates, now what" --

[maxpou]

thank you Peranders i did not think of that thus the lm 317 is essentiel. for the moment i will test without lm317

[maxpou]

i modified pcb.

[maxpou]

Hi everybody,
i have a problem with my PS, I have a good voltage but it oscillates when i don't place diodes 1N4148. But when i place diodes i don't have a lot output voltage approximately 0.9 volt. Somebody can help me?
Thank You!

[maxpou]

excuse me,
the ic it's a AD817 and not OPA134.
sorry for english.

[AndrewT]

Hi,
have you got decoupling caps on the supply pins of the opamp?
Have you fitted the recommended bypass caps to the input and output pins of the 317?

The output voltage measuring resistors 2k4 & 1k2 set up 5V on inverting input from 15V on output.

What voltage is showing on the output of the opamp?
and on the base of the 340?
and on the output?
and on the 340 collector?

How much current does the 329 need? Only 2mA is flowing through 5k1.