Foxx - Select-a-Fuzz  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
Post Reply
digi2t
Degoop Doctor
Posts: 278
Joined: 09 Feb 2011, 16:10
Has thanked: 57 times
Been thanked: 364 times

Post by digi2t »

Seeing as there are only two trace side gut shots, and no one is willing to post components, I took some time to look at this.

Image

Image

The pictures seem clear enough to make out what might be a resistor, or a cap. Cap polarities are fairly clear as well. Even a diode symbol can be made out. Wire connections to the board seem to be bigger solder blobs. Transistor E and C letters are there. So looking at, I get this;

Image

Two things that pop out at me, are the resistor/cap in series between B and C on Q2. Never seen that before. The Sustain pot set up is a new one for me as well. At least, the way I see it from the pictures it is.

Anyone interested in flinging some component values at me? I'm game to throw this on the breadboard and play with it.
No matter how many times I cut it, it`s STILL too short!

https://www.deadendfx.com/

User avatar
tabbycat
Cap Cooler
Posts: 518
Joined: 03 Jul 2011, 01:09
Completed builds: completed builds: shinei univox 6tr superfuzz with mods, vox repeater, earth sound research graphic fuzz, roland ad-50 double-beat fuzz, shinei fy-2 companion fuzz with mods, ampeg scrambler, fender blender, ep3 18v pre, dam meathead fuzz, coloursound inductorless wah, lpb1.
mods: joyo voodoo octave cap rotation, dan echo r10 mod, pb&j r10 mod, behringer vintage phaser true bypass mod, behringer sf300 superfuzz diode switch (germanium-silicon).
vero layouts: earth sound research graphic fuzz (posted here).
Location: i could tell you but i'd have to kill you.
Has thanked: 199 times
Been thanked: 53 times

Post by tabbycat »

major thanks for putting in the hard work, dino. this is a beast that needs to be released back into the wild.

i was looking at various foxx schematics and listening to clips last night and this schematic caught my eye because of the multiple-capped rotary switch.
http://www.harpamps.com/schematics/foxfzwah.pdf (thanks to harpamps for posting the schematic).
perhaps this or another foxx fuzz fuzz could be filtered through those caps? or those caps could be used as starting points for values?
it seems a lot of manufacturers in the old days readily recycled in-house circuit blocks and favoured components (shinei for example, the superfuzz spawning multiple variations, with and without wah) and maybe foxx were no different.

as an aside, that supersaturated overloaded slightly laggy fuzz sound reminds me a lot of the roland double beat ad50. that's to my ear. did foxx and roland have links or any crossover?
"be a good animal, true to your instincts" (d.h. lawrence).
"there is no excellent beauty that hath not some strangeness in the proportion" (francis bacon).
"ni dieu ni maître" (anarchist slogan).

User avatar
tabbycat
Cap Cooler
Posts: 518
Joined: 03 Jul 2011, 01:09
Completed builds: completed builds: shinei univox 6tr superfuzz with mods, vox repeater, earth sound research graphic fuzz, roland ad-50 double-beat fuzz, shinei fy-2 companion fuzz with mods, ampeg scrambler, fender blender, ep3 18v pre, dam meathead fuzz, coloursound inductorless wah, lpb1.
mods: joyo voodoo octave cap rotation, dan echo r10 mod, pb&j r10 mod, behringer vintage phaser true bypass mod, behringer sf300 superfuzz diode switch (germanium-silicon).
vero layouts: earth sound research graphic fuzz (posted here).
Location: i could tell you but i'd have to kill you.
Has thanked: 199 times
Been thanked: 53 times

Post by tabbycat »

for what they are worth...
foxx sat 1.jpg
foxx sat 2.jpg
"be a good animal, true to your instincts" (d.h. lawrence).
"there is no excellent beauty that hath not some strangeness in the proportion" (francis bacon).
"ni dieu ni maître" (anarchist slogan).

digi2t
Degoop Doctor
Posts: 278
Joined: 09 Feb 2011, 16:10
Has thanked: 57 times
Been thanked: 364 times

Post by digi2t »

Thanks Tab! Every little bit helps. I've had new info float in, including some corrections to the schematic. Here's the updated one;


I've seen the fuzz wah schematic, but in that case, the multi caps are there to adjust the voicing on the wah side. I think breadboarding will ultimately reveal what caps will sound best here.

I'm not aware of any links insofar as the Foxx/Roland thing goes, but what do I know? I'll have to have a look and see if there are any similarities in the two topologies. You never know.
Attachments
Select_a_fuzz_schematic_FINAL.jpg
No matter how many times I cut it, it`s STILL too short!

https://www.deadendfx.com/

TGP39
Posts: 2
Joined: 18 Mar 2014, 08:51
Has thanked: 3 times

Post by TGP39 »

Great job digi2t!

Steve.

digi2t
Degoop Doctor
Posts: 278
Joined: 09 Feb 2011, 16:10
Has thanked: 57 times
Been thanked: 364 times

Post by digi2t »

Thanks Steve.

Right now I have it on the breadboard. I've been confering with wiser people on this circuit, and they've been kind enough to supply me with possible/probable values. So far, I'm getting some pretty wicked fuzz, maybe too harsh though. I'm going to play around some more with it, and when I get something fairly decent, I'll post.

In the meantime, if anybody wants to chirp in with values, come on down. I'll try them out. If anyone knows how exactly the sustain pot interacts with this circuit on a real unit, please don't be shy, share.
No matter how many times I cut it, it`s STILL too short!

https://www.deadendfx.com/

digi2t
Degoop Doctor
Posts: 278
Joined: 09 Feb 2011, 16:10
Has thanked: 57 times
Been thanked: 364 times

Post by digi2t »

Finally!!

Breadboard test drive of the Foxx Select-a-Fuzz. Thanks to he-that-shall-remain-nameless. PCB's coming to DEFX soonish.

No matter how many times I cut it, it`s STILL too short!

https://www.deadendfx.com/

digitalzombie
Breadboard Brother
Posts: 71
Joined: 06 Feb 2012, 19:20
Has thanked: 6 times
Been thanked: 5 times

Post by digitalzombie »

Can you rehost all the images that seem to have disappeared from this thread?

User avatar
toneman
Resistor Ronker
Posts: 300
Joined: 17 Jul 2007, 14:05
my favorite amplifier: anything that works
Completed builds: meatolation, wobolation, ringolation clones, PAiA synths/modulars, dipthonizer clone, MOTM modules, pedal mods and repairs
Location: sacatomatoes, Kali4neeaa
Has thanked: 115 times
Been thanked: 23 times

Post by toneman »

I'l like to 2nd digitalzombie's request for the schematic. :D

I luv old fuzzes!!!

8)
Tone-to-the-Bone

d312a
Posts: 12
Joined: 01 Jun 2014, 12:00
Has thanked: 72 times
Been thanked: 10 times

Post by d312a »

Here is a verified vero layout over at tagboard forum.

http://guitar-fx-layouts.42897.x6.nabbl ... A_Fuzz.png

User avatar
modman
a d m i n
Posts: 4550
Joined: 19 Jun 2007, 17:57
Has thanked: 3189 times
Been thanked: 665 times

Post by modman »

I went on tagboard and stole the schematic back! Attached it to Digit's own post. Yeah, sue me.
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

digi2t
Degoop Doctor
Posts: 278
Joined: 09 Feb 2011, 16:10
Has thanked: 57 times
Been thanked: 364 times

Post by digi2t »

modman wrote:I went on tagboard and stole the schematic back! Attached it to Digit's own post. Yeah, sue me.
Right on!! Thanks!

Just for your own fun, you can really play around with all the input caps, make it as tame or sludgy as you wish. Lots of fun.
No matter how many times I cut it, it`s STILL too short!

https://www.deadendfx.com/

Post Reply