Boss HM-2 Wampler Mods?

[Bandwagonesque]

excuse me if this information has already been discussed and i'm somehow overlooking it in my search. Does anyone know what mods were available for the Boss HM-2 in wamplers electronics book and if there are instructions anywhere for them (my copy I ordered 2 weeks ago has still yet to arrive and I want to mod this thing before practice this thursday). Any help would be greatly appreciated.

[Bandwagonesque]

bump?

[armdnrdy]

Look at reply #5. mods for HM-2

http://www.diystompboxes.com/smfforum/index.php?topic=94508.0

Found in 10 seconds with google!

[Mark Hammer]

The simplest non-destructive, and easily reversible, mod you can do is to simply solder a piece of wire in parallel with the back-to-back germanium diode pair.  Once you identify which pads those are on the solder side of the board, a short piece of wire will do the trick.  If you don't like how it sounds, just remove the wire and you're back to where you started.

Those diodes are in series with the audio signal.  They do two things in that role.  One is to serve as a quick-and-dirty noise gate.  They will not pass any signal that is less than +/-250mv or thereabouts, so background hiss, when you stop playing, is blocked.  Start playing again, and the diodes pass signal, hiss and all, but you won't notice the hiss if you're playing.  The second thing the diodes do is introduce some crossover distortion.  Where normal clipping chops the peaks of the wave, diodes used in series with the signal clip the sides of the waveform, without altering the peaks.  So, between chopping the sides of the waveform with the germanium diodes, and the peaks of the waveform with the Si diodes, you produce something fairly square.

Bypassing the series Ge diodes will result in only clipping, without crossover distortion.    In general, crossover distortion sounds a little nastier than regular clipping, but it sounds alright when using only the bridge pickup, for whatever reason.  Given that many metal players tend to stick with the bridge pickup, I'm not surprised that Boss called it a "heavy metal" pedal.

Install the bypass, and see if you like how it sounds.  If you do, then it's a simple matter to pop a hole, and install a mini SPST toggle to either bypass the Ge diodes, or not.

Like I say, this is a very simple mod, that changes the character of the sound in an obvious way, without requiring any removal of anything, swapping anything, buying new parts, or risking destroying anything.

[Bandwagonesque]

Thanks alot armdnrdy & mark! Gonna sit down right now and try out the wampler mods and see if I can get this thing to give me a bit more output and a bit less fuzz. I have the behringer copy sitting around that I'm going to try the diode bypass mod on right after. 

Look at reply #5. mods for HM-2

http://www.diystompboxes.com/smfforum/index.php?topic=94508.0

Found in 10 seconds with google!

Yeah I was relying on the search function here and it probably didn't bring it up as I was searching for stuff for the HM2 instead of the 3. Still don't know why it didn't show up anyway as its close enough. thanks again!