Dunlop JHM1 Fuzz Face schematic?

[RRJackson]

This is kind of fascinating. This is the Dunlop JHM1 Fuzz Face Hendrix 70th Anniversary pedal that was released to commemorate what would have been Hendrix's 70th birthday back in 2012.

I'd never seen inside one of these before and stumbled across this photo a couple of days ago. It assumed it was a kind of standard-issue Silicon Fuzz Face with some marketing sprinkled over the top, but a couple of things jump out at me now that I can see inside one.

First off, it appears to have trimmers for both Q1 and Q2 bias, which is cool. Obviously it also has a 9-volt DC jack, too, which is cool. The really interesting thing is found near the BC108 transistors. Look right above each of them. There are empty transistor positions labeled, "Q3" and, "Q4"...which was unexpected.

I'm curious now. Why did they design this board to accommodate four transistors? Were they going to do some kind of Darlington Pair thing? Were they going to have switchable Germanium/Silicon transistors? I mean, as far as I know this board was only used for this limited release. Very interesting.

More than that, though, there's a spot for a third trimmer and two spots for additional electrolytic capacitors. This thing was apparently designed to do more than it ended up doing.

I emailed Dunlop about it and they confirmed that the board was unique to this one release, but the guy said he's not allowed to discuss the circuit design. Which...OK, I get it.

Anyway, I was curious to know if any of you were familiar with this board or had seen a schematic. It's kind of a puzzler.

-Rob

[mth5044]

I don't see the cap spaces, but there are two places for Diodes. Looks like D3 and D4. There are also two extra places for the 9mm pots to either side of the unpopulated trimmer space.

[mth5044]

Could it have anything to do with the other pedals in the line?



Could be the octavio, if they cram a transformer in there somewhere.

[RRJackson]

I don't see the cap spaces, but there are two places for Diodes. Looks like D3 and D4. There are also two extra places for the 9mm pots to either side of the unpopulated trimmer space.

Ah, I didn't see the D3 and D4. Since it was polarized, I assumed it was for caps. I also assumed that the outline between the two trimmers was for a third trimmer.

-Rob