Big Muff: octave-up sound

[Bucksears]

I finished up with a Mayo work-alike a while back, but I've noticed that single-note lines have a bit of an octave-up effect to them. I've also built a Gaussmarkov Op-Amp Big Muff and a GGG-tuned BMP. Neither of those have the octave thing happening on lead notes.

Is the octave effect a characteristic of a high-gain BMP circuit? Or could it be trait of the Mayo?

Thanks,
Buck

[GibsonGM]

Weird.  Phase shift problem, maybe??

[Derringer]

did you use silicon or germanium diodes ?

[Earthscum]

I seem to remember getting fairly pronounced octave up like that when I swapped in 5088's (about 560 gain), and a bit more so with MPSA13's. When I dropped in the BC109's (about 400 gain), it 'fluffed up' the sound and any trace of the oct up was gone. I got some of it back with some 3904's that measured only about 325 gain. Seemed to be the transistor's bandwidth limitations that give it more or less octave up. I tried some 2SC1815Y (about 215 each) and got about the same sound as the BC's, without the cool rattle-can effect (only way I know how to describe the sound of a BC).

This was done with 10k collector resistors and 100R on the emitters. I can't remember what it sounded like before I swapped them in from the 12 and 18k stocks (breadboard). I just used the 10k's because the MPSA's played nicer. Then I just started swapping out trannies to see if there was any real change between swapping out the C resistors and got lost in the sounds. (side note, so far I like 1st stage: MPSA13 with a 10k col reistor, 2nd and 3rd: 2n5088's with 15k, and BC109 and 10k for the 4th stage).

Oh yeah, last note... I took the emitters of Q1 and Q2 and tied them together with a 1k to ground to see what it would do, and I got some octave up from that (along with a bunch of phasing, which could be cool in it's own right).