Nocentelli wrote: ↑25 Oct 2011, 19:09
Finally got round to breadboarding this beast, and what a great circuit! Huge thanks to mictester for sharing.
Like many diy-ers, I'm constantly messing with different fuzz circuits because they're usually so simple, and even "bad" can often sound good - ideal for an inept tinkerer like me. For a long time, after trying out endless variations on the Si fuzzface, tonebender mkII, fuzzrite, bosstone, etc etc, I was pretty unsatisfied with Si fuzz circuits in general, with most sounding either too gated or gainy or trebly/harsh for my tastes. However, I tried out Skreddy's Lunar Module fuzz a while back (a fancy MKII variant with a variable high pass filter after Q1 and plenty of low-pass filtering throughout) and it hasn't left my pedalboard since! Great sound, really smooth and sophisticated, endless sustain, effortless feedback at will, and a quite respectable low-gain overdrive-ish sound with both gain controls rolled back.
Anyway, to cut a long (and boring) story short, I've recently found myself hankering after some of those gnarly/glitchy/gated retro fuzz sounds I thought I disliked, probably because the lunar module occasionally feels a little
too smooth and polite - more like a distortion than a fuzz effect: Enter the 1969 Fuzz.
I didn't want to go over old ground, and the fuzz/bias control in the 1969 looked quite interesting. I first breadboarded the circuit as per mictester's schematic, albeit with 100n caps instead of 47n at the input and coupling Q1-2. It sounds great as it is, with the "fuzz" control moving from almost clean at minimum, through classic 60's buzzy-fuzz (very much Inna-Gadda-Da-Vida/Nuggets-era fuzzbox) at half way, and on into compressed and ultra-gated edgy fuzz at the maximum.
A couple of drawbacks prompted me to tinker further; Firstly, it is
exceptionally loud so I changed the peculiar (to me) volume arrangement by removing the 22k resistor, the last 100n cap and the 390k resistor to ground: I put the 390k straight back in where the 22k had been (I didn't have anything else to hand) and put the 50k pot back in as a standard voltage divider volume control: This brought the volume down to a more manageable unity-at-12 o'clock level.
Next, I loved the range of sounds available from the existing fuzz control, but at higher settings the extreme gating can cut sustained notes off a little early, so to increase the available gain, I swapped the Q2 1k emitter resistor for a standard fuzzface/tonebender 1k gain control (I actually used a 1k2 fixed resistor to ground off the emitter with a 5k lin pot in parallel with a 22uF cap to ground, but this should work like a 1kB pot with a slightly different taper). With the gain pot at minimum, it operates exactly like the stock mictester circuit: Increasing the gain jacks up the sustain when the fuzz control is set high, and generally boosts the filth level at all settings.
A unintended consequence is that now, with the gain and fuzz set fairly high, sustained notes go on for ages, but the second you stop the note, the vicious gating cuts off potential squealing feedback: You can balance the fuzz and gain levels to set the precise sustain and gating required. With a compressor in front, notes go on indefinitely until you release the string - Silence!
Lastly, this extra gain (and possibly the new volume control) makes for a pretty bright sound, bordering on ice-pick at times: I opted for the fairly brutal but effective solution of a 3n3 cap to ground off volume lug 3. There are probably much more effective ways to achieve what I wanted to do, and as such any further suggestions will be gratefully received.
I shall tinker further this week, and post a vero layout when I'm done. Apologies for the super-long post, congratulations if you made it this far: Here's what I've got -
1969Fuzz_nocentelli edit.PNG
