VCS3 Noise clone

[Haible Juergen]

Hi !

Built the VCS3 Noise circuit on the weekend.
This simple, opamp-less noise source was something I wanted to try
since long. Interesing it is, as the transistor that produces the zener
noise
is directly coupled to the emitter (!) of the first amplifier stage, and
the feedback
loop goes to the base. 
I also wanted to try how effective the tone control works.

This little circuit sounds very pleasant. I was very surprised about the
sound with
the tone control all turned to the "dark" side: This is your instant sea
waves
sound when modulated by VCA + envelope. I compared this with a noise
source from
my JH-3 Modular, and it was different.
Reason for this?
The VCS3 circuit works as a simple 1pole LPF (6dB/8ve) when turned to
"dark".
On most Modulars, you have white (flat) or pink (3dB/8ve approximated)
noise.
Of course you can process this with a VCF, but 6dB VCFs are not so
common
in Modulars.
I wouldn't call this circuit superior to other ones, but it produces a
kind of deja
vu effect - no wonder, as the VCS3 was used so widely for sound effects
and noises.

One little dissapointment: The Tone knob works more like a 3-way switch
that like
a continuous control. Dark, Flat, Bright, but no smooth transitions.
PSpice Simulation
of the circuit confirmed this. Tried a 1k pot instead of 10k and it was
slightly better,
but you loose a lot of gain then and probably need an additional gain
stage.
Can anybody confirm this is on the real VCS3 as well ?

JH.
 

PS.: VCS-3 VCF is in progress.Increadible how tiny one can build if the
vc elements are
        diodes ...
        As there is no solution for the patch matrix in sight, I'll
probably go banana jacks
        now, with special cables that will contain the 2k7 resistors,
covered in heat shrink
        tube.