05 27 22 Serge WAD with MN3207 chips

video upload by batchas

"I am sharing here the all session, without cutting it, so you can discover like I did some sounds produced by the modified WAD.

I send a sinewave from my 258j into the input and the WAD is modulated by DUSG (random voltage from Paperface modulating DUSG and also snt to CV IN on 258j).

The WAD saturates very quickly, this is a bit frustrating and I'm still not 100% satisfied, knowing how much time I spent on trying to get the best out of calibration, but there are also some nice sounds here and there popping out. I'll spend more time anyway on it, that's for sure and I'll record on video like I always do.

The mod:
I had great difficulties calibrating the small board with MN3207, cause there’s no support available after I bought this replacement board. No video of calibration process as it was announced bythe maker/seller either.
The RETICONs on my WAD were working, but I thought I should try this replacement which as I understood it was advertised as being better. A small board to plug into the RETICONS headers.
It sounded indeed better in the demos I heard.
I did regret a bit once I read the instructions that came with the board that several resistors had also to be changed or removed on the original WAD board. I knew then I would not be able to simply swap the board and put back the RETICONs if I wanted, but would have to replace again the resistors.
It appeared then, while trying to decipher the instructions and the schematics, that the references between the instructions/schematics and my STS WAD were not matching. This also was first a source of confusion and frustration. Not only the references, but also the values given were not achieving what the instructions were saying they should. So I had to adapt values. Then after finishing the mod I was quite stressed by the huge hiss at the output, even when the module had nothing plugged in.
I did put it aside for months, not ready to troubleshoot.
Yesterday I decided to go back to the trimmers and set them again as well as possible, having them just in right position not to saturate, including the important A trimmer on the WAD board. Like with the RETICONs, the trimming is very sensitive. On the WAD board you either get no signal, a crappy one, or a decent one. I had already experience with trimming 2 x WADs. So logically I choose to set the trimmers on the position where the sound is decent.
I'm still not sure all the resistors are 100% ok, but I’ll leave it like this for now, I spent enough time on this module. I need now to take good care of the pot settings on the WAD. The settings for input signal, filter and feedback, to have a signal that is not too much destroyed and too noisy.
Also it's important not to have the VCA fully opened on the XFader to avoid the huge noise/hiss.
The B output still saturates too much, even at low volume, but I'm gonna let it go for now.

In this video we hear the direct output of the WAD. No EQ or whatever else.

BTW, I'm just sharing my own personal experience with this replacement board. I guess some advanced users will have better understanding of the modification requirements, maybe even CGS boards which match better than the STS ones when it comes to resistor references and values and will feel ok that there's no support offered after all. It was not my case, but I'm impatient now to focus on making music and have fun with some weird delays, rather then spend hours on technical details or with a soldering iron in my hands."