Guild Grizzly Fuzz Schematic

[Sparky]

I have everything that it takes to put this pedal back to stock EXCEPT the circuit board! 
Is there a schematic anywhere?  I know it's "Fuzz Face - ish" .Thanx!

[Rob Strand]

Top Gear Fuzz = Guild Grizzly
https://tagboardeffects.blogspot.com/2013/04/top-gear-fuzz-guild-grizzly.html?m=1

FYI, pcb pics
https://www.effectsdatabase.com/model/guild/grizzly
(also a thread on FSB forum)

[Sparky]

Thanx Rob.
Have you seen a schematic anywhere?  So far I haven' tracked one down  [lately]
I seem to remember seeing different values  in that circuit years ago...

[Rob Strand]

Thanx Rob.
Have you seen a schematic anywhere?  So far I haven' tracked one down  [lately]
I seem to remember seeing different values  in that circuit years ago...

I didn't find one but I quickly drew this up.
If you see anything wrong let me know.
The guild pcb has the anti-pop resistor R6 1M where mirosol's layou does not.



Damn found this under Top Gear Fuzz.

https://andydoz.blogspot.com/2015/09/top-gear-fuzz.html


Differences compared to Guild Grizzly:
- Top Gear Fuzz - the pot labels are Boost and Volume
- No 1M resistor anti-pop resistor on the schematic, although I can't see the PCB to check
- No electrolytic cap across the PSU rail
- Output cap is 500nF not 100nF.   

If mirosol's layout is for the Top Gear Fuzz then the output cap is 100nF, but that still doesn't explain the missing PSU cap as  mirosol's layout has it.

Just to be clear, the parts on my schematic can be accounted for on the Guild Grizzly PCB.    What doesn't line up is the
andydoz schematic and mirosol's layout.

I had a look for a Top Gear Fuzz PCB pic and found this
https://images.reverb.com/image/upload/s--UUXovZi---/a_exif,c_limit,e_unsharp_mask:80,f_auto,fl_progressive,g_south,h_1600,q_80,w_1600/v1469820593/bxopsct1x0ghd3bo5lgh.jpg

Fairly evident:
- 1M resistor is present
- Cap across the PSU is present.  Value is 22uF
- Cannot see output cap value

However, I can see some *further* differences  :
- Volume pot 47k
- Boost pot 2k2

Another Top Gear Fuzz PCB:
https://images.reverb.com/image/upload/s--0cbGjAru--/f_auto,t_supersize/v1622885308/qtjpssvy6qiaznnbe9cs.jpg

This resolves the output cap.  It's clearly 100nF.

Pots:
- Volume pot 22k
- Boost pot 220R.  I believe it is marked 220 then an ohms symbol.  Initially it looked like 2200.

[Sparky]

Gadzooks,,,,, that's brilliant!  Thanx!

Interesting "fuzz" control.   I've heard people complain about unity gain / volume being low on this pedal.

[Rob Strand]

Interesting "fuzz" control.   I've heard people complain about unity gain / volume being low on this pedal.

The fuzz control ends up operating similar to the fuzz-face.  There's a few variations on the way it can be done.  However, with the 220R Fuzz pot it allows the control works over more narrow and probably more useful range.   The 2k2 resistor allows the bias point to be set independent of the fuzz pot.   (Using a resistor instead of a pot has the added bonus of lower tolerance on the bias setting components.)

As for the gain you could raise the 220 ohm (R3 on my schematic) to 330 ohm or 470 ohm.   That raises the output level without changing the general operation of the circuit.

[pacealot]

I'd also imagine the difference between a 22K and a 47K volume pot might begin to affect the perceived maximum volume of the circuit — 22K seems pretty low for a FF-type, all else being equal.

(But yes, upping the 220Ω resistor is the generally prescribed solution in such cases...)

[Sparky]

I'm pondering the 220 ohm change.....yup... I think I'll do it.

I've also been curious how a "pre-gain" control at the front end of the circuit  [Joe Gagan] would be instead of the fuzz control.
[I may put that in a Colorsound 1 Knob Fuzz, too] .

[Rob Strand]

I'd also imagine the difference between a 22K and a 47K volume pot might begin to affect the perceived maximum volume of the circuit — 22K seems pretty low for a FF-type, all else being equal.

The pot shouldn't affect the level that much since the output impedance is set by the low valued 220.  What the pot change could do is shift the cut-off of the output high-filter (100nF o/p + level pot).   That could change the lows a tad and maybe sound bigger or smaller.

When I saw the 47k pot on the effectsdatabase pic it looked like a replacement and I didn't believe it.   However, the text on the andydoz site implies they traced a real unit with a 47k pot.  No idea about the 500nF output cap though - maybe need another pic to settle it.  Those clear film caps are very hard to read on the pics and you need the right angle to see the value.

I'm only commenting on what I see in the pics as I have no experience or history with this variant at all!