Doepfer A-138D

It was Dieter Doepfer who first came up with the Eurorack format now adopted by pretty well all of the world's analog modular bods. Whereas some of the newcomers to the scene produce multifunctional kit laden with a sometimes tiresome "attitude", Doepfer modules remain modest and simple affairs, each one doing one or things and leaving it up to the user how he or she wants to hook them up. The A-138D is also in this style, acting simply as input amplifier or output attenuator. I thought I'd give one a try having read a few interesting remarks on the Muff Wiggler forum (which every analog head reads), and because I have a large collection of interesting stompboxes that I fancied integrating. And the results have been interesting, especially when positioning fuzz and distortions directly after the VCO stage. Results can be hit and miss depending on box you use, the modules you are using and where you patch them in, but this kind of experimentation is par for the course and part of the fun of building your own modular system. I'd call it a successful punt!

Have tried to use this module quite a lot of times as aux/return for distortion pedals, filters, as audio input from my computer and as "pre-amp" for a spring reverb.

With destortion pedals it was very hard to supress feedback. When no audio came in, feedback swelled up horribly.

Using it with a sherman filter, it tended to color the sound too much and creating sudden resonant peaks (probably also the feedback)

While with the spring reverb, the gain was not enough to get the spring sound to a high enough level and be audible along the rest, while not being mostly amplified background noise.

Lastly, somehow the audio coming into the module bleeds through to other modules on the same rail..

Starting to think I got a damaged module..