Traced by AlexS and Fuzzhead, this is a quite tweakable and heavily modified HM2 variant with more gain on tap, more volume, two on/off/on diode switches and a very flexible four band eq.
It is a quite noisy beast when Gain and all eq controls is maxed out though but a buffer up front helps a lot. Or you can increase 1K resistor connecting to Gain 3 to calms things down. Stock HM2 value is 47k so there is a pretty wide margin to experiment within.
Layout is verified.
hi, I'm confused about the diodes, 4,5 and 6 or shottky? and diode 7 and 8 LED?
ReplyDeleteI'll change the labels as soon as I can. But the blue diodes is Shottky, the red ones is 1N4148s and the red LEDs..........is the LEDs.
Deleteyes got that, I was confused with the labels and the schematic. How many times does a schematic tell something else... ;)
ReplyDeleteA small update. AlexS noticed that IC1 is actually a TLC2262 op amp.
ReplyDeleteJust auditioned it and it sounds great, a bit less noisy and with both diode switches in off position it sounds much better than TL072 due to the op amp clipping.
builded with some rc4558 and tl084 works great!
ReplyDeleteI built this with two TL072's and an LM324 - works fine but some of the pots are a bit weird
ReplyDelete- Volume is fine
- Gain has a big jump from 0 - 9'oclock and then another big jump from like, 2-3'o clock - I might use a lin instead of a log
- some of the ton pots are a bit strange as well - for instance, when the high or high mid is at zero it cuts the volume completely - otherwise its a great pedal!
Everytime I had this kind of issue with the gain/eq pots, there was a tiny solder bridge somewhere between 2 tracks. I guess you already checked, but who knows ?...
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