DEMO Promethium Distortion (Boss HM-2 Heavy Metal)

[owlexifry]

Build Rating

5.00 star(s)

this is one of those pedals i felt obliged to build. and im still yet to fully understand it.

initially comes off as a fairly unremarkable fuzzy sort of distortion.
seems to me that most of the character and potential that makes this pedal so distinctive and crazy is the EQ.
it’s almost like the ‘Hi’ control is more of a mid control than a treble.
perhaps the ‘H’ control actually means Honk?



this was built in parallel with the HM-3 / Samarium, and went with the same building approach since they both have 4 knobs.

when breadboarding the HM-2 last year, i tried a few different Ge diode options, settled on a pair of 1N277, so that’s what’s gone into this build.
this was an even tighter fit than the HM-3, and was a lot trickier to get in there sideways.


this is such an odd circuit.
with no original to compare to, it was difficult to determine if some of the weird behaviour of this pedal is supposed to be there. e.g. the decay.
there were at least 3 or 4 times I was convinced there was something wrong or I'd made a build error, and then double checked and prodded some things, but it all looks good and I'm pretty sure I haven't lol

there wasn’t really any point for me to do a demo on such a cult / iconic pedal that has been hyped to death and discussed endlessly….

..but i like making demos, so here it is doing some swedish chainsaw at the start and then dials back to something more sort of normal and then boosted with an SD-1

 

[Morbidpale]

I love the simple pink box. The hm2 crowd (of which I am part) always makes the same old horror skulls and demons etc (which i did ).
But not you brother. Well done. Metal needs more hello kitty influence.

*incase I came off as sarcastic, I am not. Well done!

I also breadboarded it, found some value changes and diodes I liked. Really fit in better with sounds i like. Never did the work on my build though. Some day.

 

[jcpst]

i tried a few different Ge diode options, settled on a pair of 1N277, so that’s what’s gone into this build.

There’s this comment in the build docs of Aion’s HM-2:

The HM-2 uses Ge diodes here, but Schottky is a better modern replacement. They only set the gate threshold and do not affect tone.

https://aionfx.com/app/files/docs/graviton_documentation.pdf

Was the response different with other Ge choices?

 

[zeropluszero]

I like mine with dist dimed (does piss-all backed off anyway), high about 3oclock, lows about 4.
Actually hate dimed highs. Horrid noise.

 

[mhshizz]

a pink HM-2 is brilliant. love going against the grain. time to get a peavy solid state amp and practice your Entombed riffs

 

[owlexifry]

I love the simple pink box. The hm2 crowd (of which I am part) always makes the same old horror skulls and demons etc (which i did ).
But not you brother. Well done.

a pink HM-2 is brilliant. love going against the grain.

thanks
i’ve just been real keen on pink and brighter colours lately, i first had a go at taydas matte sand pink finish with a psi fuzz build and it pops quite nicely.

I also breadboarded it, found some value changes and diodes I liked. Really fit in better with sounds i like.

would be curious to see what values / mods you noted.

Was the response different with other Ge choices?

i tried D9E, 1N277 and 1N5817.
i recall barely noticing much difference between them.
it’s been a while, i didn’t write anything down, but i guess i had to pick and probably preferred the sound/decay of the 1N277s? (even though the differences were very small, they really don’t do a lot imo)