Look at my grounding please (it's a hissy G-clone!!)

(Pre-Regulator circuit
http://sound.westhost.com/project102.htm
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It must be grounding, so here is the GROUNDING diagram, (as of this first post):

Well, it's not Rod's pre-regulator by it's self.
When this gainclone amp is totaly wired, main (CRC) psu seems to be the source of the hiss (grounding?)......because I tried test powering 1 chip-amp channel from the pre-reg/+15v reg. power taps (instead of the +28v)......there was no hiss at all. The other channel powered by main psu....hiss.

Symptoms:
--loud hiss always, even at lowest volume.
--passes a signal.
Tried:
--removing star grounds (no change).
--moving star grounds to other ground points (no change).
--connecting headphones to preamp output (no hiss heard there).
--moving transformer outside case (no change).
--using lower powered (18v) transformer (no change).
--grounding transformer case.
Did Not Try:
--moving neg. spkr output to another ground place.
--connecting pre-regulator ground to other point shared by main psu ground.

(...I'm so close to being finished!!)

=FB=

Zeners can be very noisy, try putting a 22uF & .1uF cap in parallel with them.

I have to say that I would rather use a pair of 78/79 regs rather than this zener regulator.

Peter

I would say that its not the grounds causing the hiss, hum is the normal tale tale sign of ground problems.
But I would change the grounding method, looks very random.
A single to one point is best.
Except for the mic ins, I do those a little differently.