[sdiy] "Pink enough" Noise source

[Pat Kammerer]

Hi,

This question goes to Ray Wilson, or anyone who has built his white/pink
noise source.
http://www.musicfromouterspace.com/analogsynth/rayspinknoise.html

I've got the PCB done, double checked, and populated.  I powered it up and
all I get is good noise for about 1.5 seconds.  I have tried using several
different transistors, and some zener diodes.  The zeners gave the best
noise, but still for only a second or so.

Things I have changed about the circuit are;  I used .15 uF caps for C3 and
C4, just because I had them at hand.  And I used a KA4558 dual op amp in the
place of a TL072, just for an experiment, and they are more plentiful for
me.  Should either of these changes cause this problem?

I am using the buffer circuit, and that seems to work fine.

I'm also getting a lot of bleed through from a nearby oscillator.

Any suggestions would be appreciated, and I'll keep trouble shooting...

Thanks,
Pat