Oy.
This is by far the coolest, most versatile pedal I've built. Octave up, down, ring mod and, my favorite, sitar scintillating sound when I use the bridge pup with another out of phase (is that what Tim Escobedo's Jawari sound like?) Sometimes it's very reminiscent of that cheap 15$ toy synth I have at home.
As usual, I spent a whole two days workin on it, retracing and missing the same spot every single time, until the last where I went, "duh, that 100uf cap and gate connection need power...."
Voltage readings (9.4 source):
Q1 C= 5.1
B= 1.6
E= 1.2
Q2 C= 2.9
B= 5.4
E= 6.2
Q3 C= 9.1
B= 4.3
E=3.9
I used 2 2N5088's and a PNP marked 157(Motorola logo)912, hfe of 69, I scavenged somewhere, and 2 1N60's Ge diodes. I also used the resistor value changes done by JD Sleep in the null carrier mod, which I haven't tried yet.
Any other mods some of you may have done?
Ciao.
Just built one myself.
I think that the critical point of this gadget is the forward voltage of the diodes - at lower signal levels, it distorts; at higher levels it octaves and rings as well- at least, that's how it sounds to me. So a booster/attenuator at the front end might help to achieve a 'particular' sound, or possibly, switchable diode pairs. However, I'm just happy playing around with it.
it's a great little circuit. i like to boost the backend of the device w/ your favorite gain circuit. pick your poison.....
- tom
Whipped out the Green Ringer of yore build.
Debugged and hooked up Q2 collector [one of those comeback last connect that never got comeback to, dohh].
That didn't take long, and had it going, then put 047uf's twixxed Qs 2&3 I had .1's for testing [I guess], fired up with good Fuzz [who wants good fuzz...] with Si's in it. very nice Fizz and crunch on yer basic 'test' A chord [bottom of the neck, A string open]. Nice all round FIzz, A/B...si/ge diode switch would be cool.
Then I put some junctions from NTE158's measureing 1.94 and 1.99 on the DMM's diode test setting...[I'm lacking terminology here]...foreward voltage?
Really nice octave, very cool sounding haunt to it, really fun to play higher [minimum open B and above?] notes on it. Picking strength must be 're-calibrated' and settings, frequency zones [higher or lower notes] all influence the behaviour of the cct. certain notes seem to work differently than other notes sometimes even very close in pitch.
Glad I got this thing running, I had one a while back, was low in output...dunno whappenned to that one, this ones working great ... supper !!!
I built one of those a few weeks ago. It cracks me up everytime I play through it. I really like it, an ultra easy build and lots of fun funky sounds.
A trimpot over Q2.
The VR makes a difference the way it sounds, I don't know that it's really necessary, on the 'one side' of bias the octave effect is less.
One of those knobs probably better left set, so you aren't tempted to go and re tweeky tweek on it.