Doepfer

Hi Roel,

> Fascinating to hear that when you reach the highest position
> on the input of the 138 mixer, a small feedback resistor comes
> to action on the new models, compared to the older ones, which
> didn't amply!

I didn't manage to understand the set-up of your original problem 
which led on to this discussion on the A-138 mixers. The ones I have  
only attenuate, or at max settings give equal to what you put in, 
i.e. all the resistors are the same so there is no amplification 
possible. Thus I suspect what you experienced must be due to 
something else. All my 138's are marked 'v2 1996', and from what I 
know of the Doepfer strategy, I think it's unlikely there has been a 
new design in the last 12 months since I last bought one. It's such a 
simple circuit it's hard to say why it would have needed a revision 
so quickly after they started making A-100's (one possibility might 
be the inclusion of resistors to counteract the small voltage offsets 
caused by the input currents of the op amps used). Maybe if someone 
like Florian has a really early  one we could find out?

Tim