Vulcan Build report - Thanks Joe for a great circuit.

[Gringo]

Today i gave my vulcan a test drive, and it's HOT. Very hot. I guess i'll socket the 220k/.0022 section and start tweaking it to taste.

I also tried many combinations of trannies(i really enjoyed this part):

- BC549C (hfe ~600)
- BC108B (hfe ~250)
- BC337   (hfe ~120)


With the 3 549's it was LOUD, couldn't get past 2 at the vol pot, but what i heard i liked (a lot). After that i tried 3 108's and it began to sound more "classic" (with the 549's being "modern"), also i got a more pronunciated sweep with the gain pot. This also helped cleaning it at low settings with the guitar vol. Then i began trying mixed setups, the more noticeable results appeared at pos 1 and 3. Lower hfe at pos 3 -> more usable sweep at vol pot. Lower hfe at pos 1 -> more usable sweep at gain pot.

Distortion-wise, this is a high gain device. No matter what setup i used, at top gain settings it was always the same basic sound (a good one) with different shades of saturation. At middle gain settings, the "hybrid" Q setup gave me some nice rock tone. Using a progressive approach from low to high (337-108-549), sounded real nice, but not as gainy (and we need gain :lol:).

I used my own pcb layout, and it works fine (even though i managed to transfer it reversed  :shock: ). I corrected this, and uploaded it to my site, so if anyone got it before, please get the new one, or you'll go crazy (like me) reading the layout backwards to populate the board.

I'll tinker with it (i want to see what happens with something in the 400-500 hfe range), and come back with more impressions.

PD: Would mosfets (2n7000) work?? There's only one way to find out... :twisted:

[petemoore]

Great Name for a HOT Pedal !!!
 I used 470's in lace of the 220k's at the between stage reduction R slots for the last two stages, 1m5 for the first, I raised them up atop the board so I could 'tag' a parrallel R on with it for reduced values there...upon initial testing with H/B pickups, I don't think it will be necessary....gain O'plenty the way it is..
 I used 10uf emitter bypass caps for the first two stages...
 What a whomper!! I'm going to try different type actives in the last stage, which Has the trimpot for collector.
 The 10k's for collectors Q1 and Q2 also are raised so I can easily 'tag' a parallel on there...seems to be pretty well biased, but I'll take a look with the DMM in a few spots.
 All in all a great build!!
 The Vulcan's is the name of our first original band !!! Vulcan's ROCK !!!