Adding Gate Control to Ibanez Standard Fuzz

[FootSolder]

Hi Folks,
I'm trying to add a Fuzz Factory-style gate control to an Ibanez Standard Fuzz circuit. On the Factory, the B10K GATE pot is connected to the Q2 collector and the Q3 base via a 470r. I figured the closest equivalent on the Standard was replacing the 150K to ground at the base of Q2, I messed around with some values and achieved fairly controllable gating with a 470r and b50K pot, but it still adds a lot of oscillation and instability depending on the other settings. I'm sure I might have picked the wrong hack spot and certainly don't know the math. Any input greatly appreciated. Including the Madbean Pointdexter version of the Standard schematic I was using. Thanks!

[radio]

Quote:"but it still adds a lot of oscillation and instability depending on the other settings"

Thats exactly the case on the Fuzz Factory too.

Did you every tried one?

[FootSolder]

Yes, I've built a lot of Fuzz Factories but I worry replacing 150k with 470r and b50k pot could be better in the Standard circuit, just don't know the theory

[radio]

Lol , I don't know either ,just noting their is a lot of differences between the 2 circuits.

I can't imaging ,it will be feasable that easily .

But, what do you want to achieve with that "gate" control ,as you seem not to want

oscillation? Just asking to make it clearer for someone who does knowing more

what can be done

[FootSolder]

Same as a fuzz with a controllable gate like the Fuzz Factory - setting the limit to which the signal can push through the circuit, trying to get that gated sound and control some of the noise

[radio]

Just realized that Q2 is the phase-spliter for the Q3,Q4 differential pair ,responsible for the octave up

part of the circuit. So the both resistors ,emiter and collector of Q2 should not be changed.

[FootSolder]

The 10Ks on the E and C of Q2 are unchanged, Im trying to hack the 150K to ground on the B of Q2. But I freely admit to not knowing what I'm trying to do. It does kinda work...

[radio]

My bad, I didnt remember your first post correctly

[Mark Hammer]

There ARE some similarities between the Superfuzz/Poindexter/Octane and the Standard Fuzz.  But there are also some differences as well.  Here is the Standard Fuzz.  You'll note that there is no biasing to fiddle with in Q2:

[duck_arse]

you could try:

supply - 22k - 50k pot - 10k - ground.

take the pot wiper to a 100k resistor to the base of Q2 and C4(+), delete R6 and R7. you will then have a vario-bias pot - if it don't work, it wasn't me that told you, ok?

[FootSolder]

Thanks for the schematic, it is certainly different in places - I actually did go with the Pointdexter layout from tagboardeffects because I wanted the tone control instead of the tone switch.

Hmm, not sure I follow: supply - 22k - 50k pot - 10k - ground.

take the pot wiper to a 100k resistor to the base of Q2 and C4(+), delete R6 and R7

Like this sketch? And will it act like the Fuzz Factory gate?

[duck_arse]

nearly like that. you add "stop" resistors top and bottom of the pot, so it only sweeps a narrow range of volts, instead of going from +9 to 0V. this voltage appears at the pot wiper. you connect the pot to the base ONLY via the 100k [150k will do] - the 22k//pot top//C4 connection in yr dia is wrong, a hump wire, no dot there.

as for how it will act? I have no idea, it will shift the transistor bias point up and down, away from the optimum point, allowing it to cut-off on stronger signals.

[iainpunk]

i'd replace the R4 with a pot and a 1k resistor in series, should produce some gating on extremer settings. maybe/probably good to try different values to set a maximum amount of gate.

cjeers