reviving a zombie thread ....

I was reading the schematic , in the rotovibe the four stage cap values are not the 'common' univibe values , I think that is part of the rotovibe characteristic sound.

Has anybody ever tried these values in other unit such as phase 90 or some univibe clone ?

so, we can make a rat sound like a mudhoney with just two mods, 4.7uF in place of the2.2uF cap on the feedback loop and a 1uF cap in place of the 22nF on the input, interesting

I was expecting a bigger graph difference, anyway, it's clearly audible

So here it is: boss_od3_schematic - kanengomibako_dec_2021.png Hi, after 11 years I come back to this thread to share the only really useful mod I've found in this pedal, but, well, it works to tame the bass, my only complain about this pedal: decrease C13. Put a 22n or even a 18n in place of that ...

hi, such an old thread... I've seen Mentone sells a modified version with a switchable bass cut, I wonder how he can do it. I see two places for a different çap value, the cap at the output of the first Fet and the bypass cap over the source resistor of the second Fet. Any idea? could anybody confir...

the boss Instagram post reports that the tone circuit is differently tailored from the standard SD-1 in mode classic, it would be interesting to know the tone/resistor cap value.

hi,
I have an original Formula 55 pedal, it's awesome but it has a noticeably problem with my setup, the volume has a bump and it's usable in the first 1/5 of the volume range, it practically goes from 0 to loud in a fraction of the turn, has anyone noticed this? any idea how to solve it?

Intripped wrote: ↑12 Dec 2020, 07:38 It works because there is R7. C9 is just in parallel with it

right, my bad, I was sleeping

Intripped wrote: ↑11 Dec 2020, 14:10 what's the purpose of C9?

agree, that way it doesn't work, it's an open circuit

A plain FF, doesn't it oscillate at max? BC549 are quite high hfe devices

Imho there are 3 main points in every fuzz face build, using JD2F2 schematics they are: C3 - lowering it to 1uF (film) or 0.47uf the sound results less boomy, more open, since less bass hit the input of the first stage C2 - depending on versions it seems that sometimes you can find a 0.1uF for outpu...

CheapPedalCollector wrote: ↑29 Nov 2020, 12:54 They did that to reduce PSU noise.

ok, but how? I don't understand the purpose of adapting the impedance, a buffer doesn't reduce hum by itself as far as I know

I bet the double opamp was cheaper then a single and they thought 'what could we do with the other?' , although I would had use it as output buffer indeed.

what's the purpose of the buffer U1B ?

The od2 has the clipping in the normal section within the feedback loop. More of an overdrive sound that's compressed instead of the clippers to ground in between stages like the bd2. So! Remove diodes to ground and tack them in either feedback loop. I did the first one and used the second stage as...

ppluis0 wrote: ↑22 Nov 2020, 04:20 Using one 1N4148 and one 1N4007 as clipping diodes produces some kind of asymmetric distortion ?

yes, the clipping is slightly asymmetrical

31 db?? it's a huge amount of noise, it's almost a light rain type of level, are you sure of the measurement?

Maybe tailoring the bass on the emitter, like in a Marshall amp first stage? (there is a 2.7K + .68uF on one channel and a 820R +330uF on the other) btw, it worked, but I also had to change C7 (1uF -> 100nF) to cut a bit of bass and R4 (82K -> 33K), now I have fuzz on tight position and overcharged...

YATS with a fixed tone shaping

The guitar pickup is not only a resistive impedance but also inductive and capacitive combined, the fuzz face greatly interact with those element so it sound different on every pickup, you should simulate also the L and C to get a realistic sound. I know, but the simpler solution I proposed (btw I ...