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

[René Schmitz]

Hello Jürgen and all,

JH. wrote:
>>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? 

To prevent it from clipping due to the amplified offset voltage. 
Something that would be easily cured by rolling off the gain to 1 for 
DC. (A cap in series with the 1.2k)
Something which would also help in that first stage. And then one might 
even DC couple the zehner diode. But I'd rather establish a Ub/2 bias on 
the + input.

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159