GE diodes in a boss pedal

[methodofcontrol]

hey guys, i'm looking at a friend's HM-2 (heavy metal).
i'm looking at the schematic i found here:
http://www.freeinfosociety.com/elect...iew.php?id=134
and if you look right underneath where it says "boss" on the schematic, you'll
see two unspecified GE DIODES. now the weird thing is....my friend's pedal is just jumpered at those two locations on the board, and the pedal seems to work fine. but the jumpers are DEFINATELY not stock. i actually undid someone else's shoddy mod when i first opened the pedal. should i leave those spots jumpered, or should i put the GE diodes in there, and what diodes should they be?
thanks!

[Mark Hammer]

There is one point in the HM-2 circuit where the diodes are wired in series with the signal path, rather than going to ground, or being found int he feedback loop of an op-amp as they are most often found. Their replacement with wire links probably was intended as a mod to add a bit more output level.

This is a 6-of-one-half-dozen-of-the-other situation. Hotter output pushes your amp more, producing more distortion. Re-installing the GE diodes reduces signal level but produces...more distortion. Personally, as an HM-2 owner, I'm not all that impressed with it. I think you have more to gain from leaving the diodes out and the links in.

[Ray Ivers]

MOC,

That's the 'diode noise gate' circuit - the 'GE' would refer to germanium diodes, which would work better in this application than silicon diodes would, especially for pedal-level signals.

Any signal less than about .6V peak-peak will not make it through the diodes; for pedal-level signals this would include at least some amount of signal along with the noise, hence the jumpers (IMO).

It would be easy enough to throw in some 1N34 diodes and see if you like the gating effect.

Ray