[sdiy] and noisy Wurlitzers

[JH.]

> BTW weren't there some mods to the amp stages of the Wurlitzer piano to
> make the output less noisy? it might have been replacing some of the
> carbon film resistors with newer metal film ones.

Noise and Wurlie is a never ending story for me.
At the moment I'm happy, I mean HAPPY, that all I hear is some high level
of white noise. No cracking sounds that are louder than the music (can you
say
negative SNR?) anymore!
I should check the internal amp, but we have signals in the hundreds of
millivolt
range here, so this is all very strange. I also have an increadible bass
boost (need
a 1pole 6dB HPF at 200Hz between the Wurlie and any preamp), and I suspect
the two problems are related.
I think maybe (maybe!) I have one ore more tines too close to the pickup
frame,
increasing the overall capacitance. I have simulated this once (modeling a
variable
capacitor to be the AC source in PSpice), and the results suggest that too
high
capacitance on the pickup (with the variable capacitance of each tine being
unaltered - execept for the fauly one(s) ) would cause such a bend of
frequency
response. And it might also decrease the SNR of the whole electrostatic
system
(pre internal preamp!) by overly loading the sources.
I'll look into this depper some time.

JH.