Superfluous Superfuzz components?

[Derringer]

1. What's the purpose of the elecytrolytic that comes after the diodes?
   I took it out and seems to work fine without it.

2. I like the sound going through the T-Notch with a pot between the cap
    and ground (thank you Mr. Hammer) so I just chopped out the 47K
    and 10K that come right before it. I tried it with just a 47K to ground
    and without anything to ground there. Didn't make a difference either way.
    Any reason to have a resistor to ground there?

3. I ditched the 100K on the output to. It didn't sound different without it.
   Any good reason to leave it there?


Thanks!

[drewl]

#1- Stability for crappy leaky 60's germanium diodes?
Don't know.
Hey while we're here, I wired up mine and stuck in some generic 2N2222's in the sockets and it looks great on a scope.
The enclosure should be dry by tomorrow.
Anyway, I noticed that the 10k bias can remove the octaves, anybody make that swithcable so the octave is switchable?

[DiscoVlad]

1. What's the purpose of the elecytrolytic that comes after the diodes?
   I took it out and seems to work fine without it.

DC blocking for the filter section? Though the output transistor stage has a coupling capacitor for this reason anyway.

Having a look at it in spice, removing that capacitor only slightly alters the frequency response below 2Hz so the effect it has is inaudible anyway.

2. I like the sound going through the T-Notch with a pot between the cap
    and ground (thank you Mr. Hammer) so I just chopped out the 47K
    and 10K that come right before it. I tried it with just a 47K to ground
    and without anything to ground there. Didn't make a difference either way.
    Any reason to have a resistor to ground there?

The 47 + 10k resistor are a voltage divider, which attenuates the unfiltered signal to be close (not in the ones I've built?) in volume to that of the filtered (1kHz notch) signal.
If you're hard-wiring the filter so that it's always on, these two resistors aren't needed.

3. I ditched the 100K on the output to. It didn't sound different without it.
   Any good reason to leave it there?

Thanks!

That's a pull-down resistor so that the output doesn't float when the effect is bypassed.
Its purpose is like an input pull-down, to lessen/stop the "pop" which happens when you switch the pedal in and out.
So, it's not strictly necessary, but having one there is in most cases, a good practice.

[DiscoVlad]

#1- Stability for crappy leaky 60's germanium diodes?
Don't know.
Hey while we're here, I wired up mine and stuck in some generic 2N2222's in the sockets and it looks great on a scope.
The enclosure should be dry by tomorrow.
Anyway, I noticed that the 10k bias can remove the octaves, anybody make that swithcable so the octave is switchable?

Try changing the 22k resistors in the octave section to 15k, or 18k. That should be enough to compensate for the 2 x 5k of the bias trimpot.

[Derringer]

awesome, thanks folks!

and yeah, I do have a 10K pot between the 22K resistors on the octave amplifying transistors

I had it on my scope today and no matter where I turned that pot to, the octave was still there. It just seems to adjust the amplitude, and to a lesser degree the shape, of the octaves so that you can better match them.

The expander pot however can dial out the octave ... at least with a sin wave

I'd imagine thought that you'd have to beef up the final gain stage to run the effect at a suitable level with the expander backed off to where the octave is absent

[petemoore]

   It looks like there's a 10uf / 5v cap sitting right next to 9v supply, I'd feel safer with a 16v rated cap there.

[Derringer]

but then you'll lose the inherent "exploding capacitor" sound


heh  I never noticed that it was only 5V .... good eye.