[gracky]

Well, I tought it could be nice to use Gilmore's PSU with my opamp amp (using OPA637/HA5002) of META42 like topology. And I tried to build one. Separatedly, the PSU seems to work. Without load (e.g. leaving the sockets empty), it gives supposed voltage (+-15v) well while the chips put, voltage goes hardly over +- 2v. Also, measuring current of biasing current source without chips, its current is very smaller than expected (about 1/5 - 1/10, I don't remember exactly,

) about 0.8 - 1 mA. (I'm using lm334z). Tried to decouple power lines to OPA548Ts with 0.1u caps with no improvement. Is the PSU designed to supply less than required by IC amps? Or 0.05% register matching is necessary to this unit? (I didn't register matching.) Or maybe 548s are demaged, or decoupling didn't work well...

Any comment will be welcomed. Thank you in advance.

 

[kevin gilmore]

On the minus supply opamp a .1 from pin 2 to ground
is almost always necessary.

Other than that, i use this supply on every analog audio
project i build. Anything from 10 to 250 ma per side.

 

[gracky]

Quote:

Originally posted by kevin gilmore On the minus supply opamp a .1 from pin 2 to ground is almost always necessary.

Thank you Kevin, but I did so also. Do you have any other idea about the cause of such phenomenon?

BTW if I fail with this PSU, I'd consider using 317/337s twice for double regulation. I'd be also very grateful for any comment on such design.

 

[kevin gilmore]

need voltages at various points before and after the load
is applied. is +/-24 volts still 24 volts under load. Is the
reference always +5??

Did you forget to tie ilim to v-??

here are the pin numbers and voltages

positive opamp

1 +5
2 +5
3 -24
4 -24
5 +24
6 +16.4
7

negative opamp

1 0
2 0
3 -24
4 -24
5 +24
6 -16.4
7

 

[Rpell]

Quote:

On the minus supply opamp a .1 [uF] from pin 2 to ground is almost always necessary.

I experienced oscillation in the minus supply opamp after I tried adding some small local decoupling capacitors to the main amplifier board. The supply returned to normal after I removed the capacitors, but it is good to know that a capacitor at the inverting input of the minus supply opamp should prevent this.

 

[gracky]

Quote:

Originally posted by kevin gilmore Did you forget to tie ilim to v-??

It was that, I can't thank you too much. Thank you Kevin.

However, the unit oscillate. Its hard too see in which condition it does. Sometimes it does sometimes doesn't. I've tried decouplings yesterday without success. So my frustration goes yet.... -_-;