Timmy and Fuzz Face Bass Mods

[Locrian99]

Hello,

I need to throw together a couple circuits on PCB's I already have for a bass player.   Unfortunately I don't have a ton of time to experiment, also I don't own a bass to try the circuits out with.   

The Fuzz face is a pretty standard PNP Germ version.   I figured raising the input capacitor up to I was thinking 4u7, but that might be a bit high.   And adding the caps between base and collector of 100p would likely suffice here.   I can just tack the caps on the solder side of the board, the board im using doesnt have a spot for them.   

Timmy I almost wonder if just leaving it be will work fine, thought increase the input cap.   Is there anything else thats commonly done?   

Oh yes and I'm assuming its just cap values, but for a range master to be more bassfriendly






Both boards I had made are close enough to these schematics (and they are drawn better than mine lol)

[GibsonGM]

I'd say test different in/out cap combos, but be sure to PLAY the bass as you do so. It's interesting to note that sometimes, adding a lot of low end back into the signal can turn it muddy and ruin the fuzz, etc.  Maybe even use an EQ pre/post to get an idea of how things would sound with more/less 200Hz or so. 

There's a fine line between increasing the lows to give the bass body and making it sound 'Blaaaaat', ha ha....

[Mark Hammer]

We too often think of bass as merely frequency content.  But the more metal you wiggle over a magnet coil, the more output they produce.  So even on a regular guitar, the wound strings put out a hotter output than the unwound ones.  (Hence the design of the Tube Screamer, that provides less gain for the low end, so as to provide roughly equivalent clipping over the whole fingerboard.)

Mike/Gibson's recommendation to try out different caps is a solid one.  To that I would add that one should think about how much bass is pushing any clipping stage/s, versus how much bass is in the final output.

The standard Gain control on a Fuzz Face provides for a variable resistance between the emitter of Q2 and an electrolytic cap to ground.  The value of the cap sets how low in frequency the AC gain is applied to.  The cleverness of the design is that it does that by tapping the Gain pot so that only some of the pot's resistance is in series with the cap.  But there's nothing that says that resistance can't be supplemented.  So, for instance, the wiper of the Gain pot could go to a 100R resistor and 100uf cap to ground, as well as directly to a 22uf cap.  Gain would be applied to lower frequency content via the larger-value cap, just not as much as the usual fuzz bandwidth.  Whatever the Gain pot is set to,, there would always be 100R more resistance going to the 100uf cap.

Those are just hypothetical values, as I don't even know how to do the math for it.  But the central idea that differential gain can be applied to the low end is quite sound.  Perhaps someone who does know the math can chime in with suggested values.

As for the Timmy, it already does provide a means for adjusting how much gain is applied to the bass in the clipping stage.  You may wish to up the values of some of the treble-cut caps, like C2, C5, and/or C11.

[Gus]

For bass and a FF you might want to try .1uf or even lower.
Adjust the input cap at the volume you will use the FF.
Remember FF like circuit like to be the first effect after the guitar or bass due to the interaction with the cable and LRCs of the guitar or bass.

As posted above by GibsonGM much lower frequencies from the bass can make things muddy because due to the lower distorted/clipped notes "hiding" the upper distorted frequencies.

If you look at posts others and myself have made over the decades(IIRC Aron's forum in some form started around 1996) of this forum you will find posts about switchable or blendable input high pass network into fuzzes and distortions.

[abc1234]

I have a Timmy clone, and from what I remember there's no low end loss on bass. If there is, you can probably correct this by adjust the caps in the low frequency tone control section.

With regards to the Fuzz Face, check out the TecAmp Dream Buzz, which is a bass-friendly FF. I've played around with the circuit on a breadboard, and I think the main thing that resulted in more low end was a higher value cap on the Fuzz control off Q2.

However, in my experience pretty much all distortions/fuzzes/overdrives don't so much lose low end, it's more that at higher settings they simply because they produce too much high frequency (or at least non-frequency) content which drowns out the low end.

The best way to avoid this is to not crank the gain, filter out the high end, or have a clean(ish) blend.

So it's best to find out how your bass player intends to use these circuits, because if it's at low to medium gain (plus simply rolling down the tone control on the bass) you probably won't have any problems.

But if it's at higher settings, you'll very probably have to make some tweaks to the circuits to retain low end/lower the high end.