[sdiy] CA3130 in Polyfusion Noise module...should a new one work?

[Rutger Vlek]

Hello everyone,

thanks for all the help. I works now! I threw out the CA3130, I removed the 
capacitor between pin 1 and 8. And I placed an LM741 instead. I changed pin 
4 to -15V and it works like a charm :).

The offsettrimmer indeed works very very very very strange ;). I very 
carefully set it to exactly half way, and that works, but if somehow a 
slight vibration changes the position it totaly stops the noise from 
working, so i might get trouble with it in the future.

Anyway, i'm a happy man now. Next thing is getting the S&H to work. But this 
should be ok since Ray Wilson designed it ;).

Greetings and many thanks,

Rutger

>From: "JH." <jhaible at debitel.net>
>To: <HA.Synth at t-online.de>, "Rutger Vlek" <rutgervlek at hotmail.com>,        
>"James Patchell" <patchell at cox.net>
>CC: <synth-diy at dropmix.xs4all.nl>
>Subject: Re: [sdiy] CA3130 in Polyfusion Noise module...should a new  one 
>work?
>Date: Wed, 21 Dec 2005 23:01:52 +0100
>
>
> > The schematic is not OK...as drawn...the CA3130 stage will not work.
>
>Strange drawing indeed. Just look at the second stage with that stupid
>"white offset" trimmer. Why would you adjust the DC level, when the
>stage is AC coupled at input and output? And if for some obscure
>reason you would, then why make the sensitivity of the trimmer
>3750V (!) per one full rotation ??
>
>And the first stage (CA3130) will either work, half wave rectify, or
>not work at all, depending on amount and polarity of the opamp's
>offset voltage.
>
>JH.
>