too much ripple
 

I have built my regulated power using the LM337 and 317 and made the changes as suggested but still get about 1mv of ripple at the ouput. This also appears at the preamp supply pins even with onboard suppression and its appearing at the output as a low hum. The ripple occurs about evey 8ms. Is this the best that I am likely to get from these regulators. The ripple at the reg input is about 38mv pk-pk Has anyone had anything better from these.

Steevo

NOTE: I am a newbie

How about pre-regulating?

power supply
 

I never thought of that, will it work.

Steevo

If it is below 35V, search using preregulator as the search term and my Nic in the right box...

1 mV of ripple is not worth worrying about.

ripple
 

1mv seems to have an effect on my preamp, the low level ripple is audible through my power amp when I cobbect it to my preamp. I thought the Ne5532 opamps PSRR would have taken care of 1mv but it doesnt seem to have. When I turn of the transformer the ripple and therefore the noise dissapear. Apparently because of the high gain inside the feedback loop they are very sensitive to noise.

Steevo

Steevo, have you hum with any load?

Re: ripple
 

Are you sure you don't have some kind of earth loop? Opamps are very good at rejecting supply noise

Regulator ripple
 

I could have an earth loop, not sure how i go about detecting where it is though.

Steevo

What's the size/value of the filtering caps???