This is a handy little mod for the Univox Super Fuzz - especially for those who always leave the tone switch on the notch setting.
Instead of a tone switch, there's a pot from the 100n capacitor to ground in the bridged-t notch filter, so the amount of notch can be dialled in. If you really want to, you can have almost no notch... but why???
I usually like to include an octave pot in my builds, but I decided to keep the knob count down on this one. Easy enough to add; there's space for this if you want to add it.
UNIVOX SUPER FUZZ - NOTCH FILTER MOD - VERO LAYOUT
UNIVOX SUPER FUZZ - ON THE BENCH
I used a few old transistors for low gain and a Motorola dual transistor for the long-tailed pair. The diodes are Soviet-era D9B, not that it makes much difference on a Super Fuzz (they don't really do much).I intentionally made a few resistors standing to leave room around the many 10uf capacitors and the sizeable dual transistor. 2 x 47uf capacitors have been used instead of the usual 100uf on the power filter, as the 100uf was too cramped.
It works great... first up. haven't any low HFe npn's just yet but expect that it will perform even better.
ReplyDeleteAlso you mention and octave pot... what modification needs to be done to achieve this..Oh yeah, its definitely verified. Thanks.
Hey Massatony - good to hear it fired up for you. For the octave pot mod, instead of the two 22k resistors from the base of Q4 & Q5 going straight to ground, they go to either side of a 10k pot, with the wiper going to ground - you can balance up the two transistors for better octave (or less if you prefer). This is sometimes included as an internal trimmer on some circuits. Can't believe I haven't included this on a layout somewhere...
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Thanks for that.... great site!
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