Looking for nice power supply designs

[Progg70]

I have a Class-A amp who needs about +/-16V and 4 amps as idling current. With an ordinary design with 60 000 uF for each +/- the trafo have 700VA 16V I have to much hum in the silent parts of the music. Can some one give me tips for nice power supply designs?

Regard

Progg70

[gootee]

Can you post a picture of the internal connections of the amplifier that you have built, and, if possible, a schematic? Your hum problem may not depend only on the power supply.

[AndrewT]

Hi,
post schematic and photo of the wiring, if possible.

Is it single ended or push-pull or bridged?

[Progg70]

It is a single end config. If I change to lover current there is no problem with hum, very low hum. I have already tested different config. And I use a good one. I only need a good power supply who meets the current in idle 4 amp.

[AndrewT]

Hi,
try using an rCRC PSU or better still rCLC PSU.
the r= transformer resistance.
C=smoothing capacitance. split into two stages.
60mF sounds about the minimum for a 4A bias current.
I reckon you should add an extra stage giving 0r2, 20mF, 0r2, 60mF. and see if that helps.
But, have a thorough look at your power grounding and ensure it is separated from your signal grounding.

[Eva]

A switching mode power supply can produce a humm-free regulated output voltage without audible noise or bulky capacitor banks and toroids. Sometimes there are bargains on ebay...

[Progg70]

OK I try something out…