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

[Rutger Vlek]

Aaah, it working now! A new Op-Amp did the trick. I probably blew when i 
tried to get the Reverse Breakdown voltage right for the noise transistor.

The only problem now is that the noise is waaaaaaay to soft. Where could i 
best increase the gain? And how? Should i change the 150K resistor in one of 
the op-amp feedback loops or should i change the resistor that ties it to 
the ground? And on what op-amp shall i do that?

Regards,

Rutger

>From: HA.Synth at t-online.de
>To: "Rutger Vlek" <rutgervlek at hotmail.com>
>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 19:30:59 +0100
>
>The  CA3130 is designed for unsymetric supply voltage. The schemo looks OK.
>The maximum voltage between +Ub and - Ub is 16V. If you tried it with more
>then +-8V symetrical then the OpAmp may be gone.  The negativ input voltage
>must not exceed -0,5V under -Ub at pin 4. The 3130 has problems with
>capacitiv load. I looked this up in an old book. The suffix E is not noted
>here.
>
>Try to replace it with a normal OpAmp (use symmetrical supply) to ensure 
>that
>everithing else is working fine.
>
>Measure the input voltage/signal. If it exceeds -0,5V then this should be 
>your
>problem and damages the 3130
>
>HA
>
>
>Am Mittwoch 21 Dezember 2005 18:34 schrieb Rutger Vlek:
> > I was just wondering about the CA3130 op-amp. Has it changed since it 
>was
> > first produced? I'm doing a remake of a Polyfusion Noise module and in 
>the
> > first gain stage after the noise generating Diode (or transistor in my
> > case) a CA3130 is used. But in the schematics I found on internet
> > (synthfool.com) the CA3130 is powered with only +V and not with -V. 
>Instead
> > pin 4 is connected to Ground.
> >
> > In my remake I couldn't get the CA3130 to work...and I don't know why.
> > Signal is going in, and the signal path after the output pin is correct
> > too, but somehow my Op-Amp won't amplify. That's very strange. In the
> > current datasheets on internet about the CA3130E by Intersil i read that 
>it
> > does need a +V and -V, but when i tried it the chip ran very hot and
> > probably died. So i had to buy new ones.
> >
> > Is the op-amp configuration in the schematic
> > (http://www.synthfool.com/schematics/polynoise.gif) still working with 
>the
> > newer CA3130's???
> >
> > Regards,
> >
> > Rutger