Modding the DS-1

[Steben]

Hi again,

Anyone who can tell if it is a wise decision to change the second transistor (before the opamp) into a JFET stage? I want to add more second order distortion, you see, followed by symmetric clipping (the PLEXI way).

[petemoore]

FUZZ CENTRAL has an extensive article about DS-1 mods.
 I would not mess with any of the Jfets if the bypass is working.
 I would change the opamp before any discrete devices..if that transistor isn't listed as a mod at FC, I'd leave it alone...
  EDIT: Probably a good mod, of course you'll have to change the biasing arrangement, and may have to 'diddle' with it for optimal results, but Jfet sound in that position...[I actually looked at it for a minute]...probly a nice sounding mod, providing the Jfet has sufficient gain for the drive level you're looking for.
  My Cloned DS-1 mod unit has a Fetzer Valve driving it, and sounds super nice.

[stm]

The idea of changing the bipolar gain stage with a fetzer valve is interesting.  Overall sound should change in terms of harmonic content, and perhaps you will end up with less overall gain, which is not necessarily bad.

I think it's worth the try (just be careful not to damage the PCB).  The fact that it hasn't been done is more like a challenge rather than something not to do!  :lol:

Good luck, and let us know how it does!

[Steben]

Mind: My idea is to deliberately bias the fet towards 4 to 3 V, not 4.5V. The fetzer is biased to 4.5

[stm]

"Let your ears be the judge", they say.  You just need to use a biasing pot on the FET drain and adjust to whatever sounds good to you.