Fairfield Circuitry - Four Eyes Fuzz

[Thaxt]

Les JFETs est (etait?) formidable.

[Crumbchildz]

Ah poop. I was just talking to one of my buddies about designing a box that split your signal into 3 bands and fuzzed the bands differently, and you'd have control of over the output level of each fuzz. Fairfield not only beat me to it, but made a far more elegant design than I could ever come up with. Poop.

[RnFR]

well, Paia beat Fairfield, so don't feel too bad. check out the Quadrafuzz. it looks pretty sick- and might give you some ideas!
http://www.paia.com/ProdArticles/quadrafz-design.htm
I would do the fuzzing differently, and probably reduce the bells and whistles, but it's all there, with an article my mr. anderton himself.
man, now you got me thinkin! I wanted to build it, but was always put off by the QF due to it's massive parts count for a fuzz, and the fact that it's rack mount. a redesign may be in order...


also, I just ran through an old manual for a Paia filter, and it had a block diagram for a second order state variable filter, which showed hi, mid, and lo outputs, so the filter itself does the splitting of the frequencies here.
http://www.paia.com/talk/download/file.php?id=167
I wasn't aware of that, I just thought it used separate hi, lo, and band pass to split, then used the filter similar to an aural exciter type thing. it is a very cool idea! the only thing I don't understand is how those vactrols are implemented.

I still think I might want to try that modified QF, as it seems like it might have more separation of the bands, where as I would guess the bands are more interactive with the SVF?

[Crumbchildz]

The issue I always ran into was in order to get the slopes of the crossover steep enough but still variable, you're looking at varying several resistors at once. I couldn't get FETs to work (cuz I didn't know what I was doing at the time), but for some reason I never thought of using LED's and LDR's. I think the LDR section of the vatrols are being used in the filter as the variable elements to change the crossover point. Simple and crazy affective. The QF is a pretty cool design, but I can't stand rackmount stuffs. I'm agonna take another look at my design and see if LDR's would work.

[juanro]

Is this a coincidence, or what?
I just saw the Fairfield Four Eyes mentioned in another thread and a little search drove me here.
I started reading... and remembered that yesterday I was browsing my archive folder and saw this:

Code: Select all

The gigantic Japanese Electronics Book
Downloaded from http://www.experimentalistsanonymous.com
Download courtesy Colin Raffel <colin@experimentalistsanonymous.com>
Thanks to Jun Tatsuoka <Soundfun@prodigy.net> for scanning and sending it all.

Also, I seem to remember that the Mutron III uses a similar state-variable filter with simultaneous LP / BP / HP outputs controlled with vactrols... just ditch the envelope detector and use a pot (or external pedal) to control the sweep.

So we have the PAiA Quadrafuzz, this one (very nice I must say) and I was thinking in a mere two-band distortion, psch...

Juanro

[ppluis0]

I think Mr. Fairfield deserves to any member of this forum do the honor of practicing reverse engineering of this pedal.

To uphold the prestige of this forum, I say ...

[okgb]

I think someone else posted this here , but the pedal
http://ironether.com/pedals/qf2/
QF2 Analog Multiband Distortion

The QF2 is a unique distortion pedal, which splits the signal into four frequency bands, then sends each band through its own separate distortion unit. The frequency centers of all four filters can be swept proportionally over a range of 3 octaves. This complex parallel processing creates entirely new sounds, and allows for playing complex chords with a smoother, cleaner sustaining sound with minimum harshness and increased clarity.

The QF2 is based on the original “Quadrafuzz” rack-mount effect invented by Craig Anderton in 1985. Taking this concept several steps further, the QF2 has been redesigned from the ground up, adding more resonance control on each channel, a frequency control that sweeps all four filters simultaneously for unique vocal-like qualities, and expression pedal control over this frequency knob for real-time expression.

The pedal can create sounds from gritty low-gain overdrive with enhanced clarity; singing, sustaining smoothness even with complex chords; grindy, growly distortion; massive crunchy fuzz with definition; analog octave-up; and unique synth and fuzz-wah sounds.

The QF2 Gold is voiced specifically for guitar. The QF2 Copper is voiced for bass, keyboards, and drums, and includes a Mix control to blend the clean signal with the dirt.


I have an old piaia one , haven't fired it up in years and thanks
for posting the schematics

[Jack Deville]

Now that solder side picture made me grin. I have nothing but respect for that kind of smart thinking.

FWIW, I've been employing this practice since 2009, starting with BUZZMASTER's PCB.

Perhaps Fairfield came to the same conclusion I did on his own. I know I though I was sure clever.

Even still, people attempt to copy my layouts and designs.

[okgb]

Bump for for,
I wouldn't mind a pedal version of my paia rackmount , I'll look for the schematics ..........

[mmolteratx]

Man I wish I still had this one. Would be a fun afternoon or two reversing it.