Craig Anderton Quadrafuzz - TL074 version - with mods

[MAO]

Updated by request for TL074 op amps.  

This TL074 layout required quite a few changes from the original layout I had posted, so proceed with caution until it is verified.  

Changes/notes in addition to the TL074s:

1. As with the previous layout, I have omitted the electronic footswitch, filter output jacks, effects loop, the line level in/out and the +/- power supply.
2. I updated all the 5nf and 5uf caps to the more common 4n7 and 4u7.
3. per the notes in the previous layout post I changed the socketed filter resistors/caps as follows: Low-Mid - 150k/150pf  High-Mid - 220k/100pf and High band - 270k/180pf.
4. Added an optional 1 meg input pulldown resistor.
5. The socketed 10pf cap and 220k resistor in the lower left corner of the board may not be needed.
6. omitted the optional line level output resistor socket.
7. The yellow caps should be matched pairs. (4n7, 10n, 22n and 33n)
8. CLR for the bypass LED has been taken offboard
9. The "Resonance Peak" resistors are socketed for experimenting with the peaks. Those are the 4k7 and 10k resistors at pin 2 of the "Q" switches (SW2-2, SW3-2 and SW4-2).
10. The 2k2 resistor at bottom right of board is socketed. Higher value will increase gain before tone control.  

Here are some useful links:

Previous RC4136 layout with suggested mod notes: http://guitar-fx-layouts.42897.x6.nabble.com/Quadrafuzz-Craig-Anderton-1995-td16032.html 

Original Quadrafuzz circuit analysis by Craig Anderton
http://www.paia.com/ProdArticles/quadrafz-design.htm

Stripped down schematic by Mark Hammer which was the basis for the layout:
http://smg.photobucket.com/user/mhammer/media/moddedQUAFZSCH.png.html

Mark Hammer's mod suggestions, most of which have been included in the layout:
http://www.diystompboxes.com/smfforum/index.php?topic=47362.0


 
Reverse Image for cuts



Here is a daughterboard to power it, Madbean's Road Rage:
 

Quadrafuzz BOM (* are modded values)
2k2-4
3k3-4
4k7-2
10k-8
22k-5
39k-1
100k-6
150k*-1 Originally 100k
220k*-2 Originally 100k
270k*-1 Originally 100k
470k-1
1M*-1 Optional

10p-1
10p*-1 Originally 220p
100p*-1 Originally 220p
150p*-1 Originally 220p
180p*-1 Originally 470p
220p-1
1n-1
4n7*-2 Originally 5nf
4n7*-2 Matched set, Originally 5nf
10n-1
10n-2 Matched set
22n-2 Matched set
33n-2 Matched set
4u7*-9 Originally 5uf

5k Log or Lin - 5 (I prefer linear for all 5)
100k Dual Lin -1 (not crazy about linear taper on this one, may try log)
500k Lin -1

LED, red diffused - 8
SPDT Toggle Switch - 4

TL074 -3

Road Rage BOM
10R-1
100n-1
10u-2
100u-1
1N5817-1
1N4739-1
TC1044-1

[SonusFluxa]

Thank you for the layout! One small request, I'm putting together a BOM right now and am having a hard time reading some of the values. Do you have a higher resolution copy of this?

I'm really looking forward to trying this one out.

[Hozy31]

Going to have to give this one a go. Will check my stocks and if i have everything available will do it at the weekend.

[MAO]

Added BOM

[SonusFluxa]

Thanks a ton, that cleared up a few components I had in question.

[SonusFluxa]

I got all of the parts I needed in the mail yesterday, and stayed up until the wee hours finishing my build. Happy to say that it started right up with no hiccups to speak of! I can see this being a solid addition to my live board due to the versatility of the fuzz tones you can get with this guy. Went into this more as a curiosity and a challenge, but super happy with the results.  Thanks again MAO .

Out of curiosity, what did you use to box your build? I've got a 1590BB staring me down from the shelf but I'm wondering if that would be more of a headache than its worth.

[MAO]

Very cool!

Funny, I was up all night when I drew up the new layout... I was worried I
may have botched something since there were so many changes from the
original 4136 layout I had posted. Glad it worked out!

I went with a 125bb, (same size as 1590bb but a little deeper like a 125b)
Probably could fit in a 15900bb if you turn the switches sideways and drop
the stomp and jacks down towards very bottom of enclosure. I didn't like
the way that looked so I opted for the 125bb (small bear)

I think I have some pictures posted in the 4136 version.

Questions:
1. How do you like the sound of chords through the quadrafuzz? To me,
nothing else sounds like it, pretty cool.

2. I wasn't crazy about the taper of the tone control. How does yours
respond? Mine was only useful towards the end of the rotation.

3. Did you go with the cap/resistor mods?

I agree, great pedal (with cap mods :0)) Don't know why this type of design
didn't take off. I asked Craig Anderton the same question back in the mid
90s, he said to me "nobody cared". Funny side note, at that time Craig also
said to me he was surprised about the interest in his 2 books, as he
thought that the analog designs were played out and that digital circuits
would take over.

BTW, If anybody else is considering this build, I don't think the YouTube
videos on the new QF2 version do it justice. I wouldn't base my decision
off those videos.

[SonusFluxa]

Thanks for the heads up on the enclosure. I just ordered a 1590BBM which I believe is similar in size to the 125BB.

Re: your questions:

1. Chords sound great, I feel like there's a bit more clarity given to the individual notes in the chord than a lot of other dirt circuits, while still retaining a heavy, fuzzy sound (if that makes sense). That's one of the things that won me over, since I mainly try to play 'odd' chords (ie not power chords), not lead.

2. I agree that I'll mainly be using the last 10% or so of the tone, but I can also see adjusting it manually during recording for a interesting effect. Expression pedal control would be interesting (as if the off board wiring isn't already enough).

3. I used your values, not the values from the original. Good call.

Great bit of info re: Craig Anderton. I'd be interested in knowing what he thinks about it now. I'm in the middle of reading an interview with him now to see what info I can glean.

I second the sound of the YouTube vids, definitely sounds fuller and more unique in person. I'll try to upload a video as soon as I get it boxed up and presentable.