Fuzz Face clone, Treble roll off. Suggestions ???

[Melanhead]

I've been tinkering with a fuzz circuit based on the 70's Fulltone pedal but with some mods of course

I love the tone when the fuzz is cranked ( used 2 BC108 HFE 250 and 450 ) but as the guitar volume backs off it gets a little brittle ... I read the geofex fuzz face article and tried a few tips discussed there but I can't seem to roll off the top end, which I'm guessing is in around 4-5k at the top of the speakers frequency range. Anyone tried a low pass on one of these just before the output Any other ideas ? ... It's liveable as is but sound like a fender with the bright switch on

[Steben]

Is it like the Roger Mayer Axis Fuzz?
If it is I would suggest lowering the bias resistors to lower values (resulting in the same bias of course!), making it lower input impedance. This gives a more classic fuzz face treble off.

[Bernardduur]

On fuzzcentral they reduced treble by putting a cap between the +9V and the signal out of 0.047 µf here.

[Steben]

However, the more I think of it...
the '70 and the axis are made to sound "different" and "brighter" than the stock Fuzz Face. Maybe you should build a simple FF? Or if you already did: accept the pedal for what it is? 

In all other cases I would really consider lower input impedance.

[Melanhead]

thanks guys I'll give the suggestions a shot ... or may just leave it alone

[vseriesamps]

How's the volume knob on your guitar set up? Mine has a .001 cap across it so that it retains high end (i.e. gets thinner) on the way down. This is very useful for getting clean clean tones out of an amp, but it could cause the sort of brittleness you're talking about in conjunction with your pedal. Removing such a cap would make the tone a little darker as the volume decreases, or there's a schematic up at fralinpickups.com to have your tone stay the same all the way down.

Maybe it'll help you to attack it from a different angle.

PS you want to roll of the volume to clean it up? or just for volume difference? playing much softer works well with that sort of fuzz

-
k

[shredgd]

I built a fuzz face based on the 70's schematic, too, and I found it too bright as well, so I raised the value of the cap between the two transistors' collector to 47pf, and changed the volume pot to 500k to retain more bass.
Now I'm happy with it when playing at home, but I still haven't tried it at full volumes.
I hope this helps, bye!

Giulio

[Eb7+9]

the other night I built a most wicked Antiquity using 2N2924's (Ge PNP) and  implemented top-end roll off using a 100kB pot and 0.047uF cap between collector of the last device and -9v rail ... try that out 

btw, thx Joe - inspiring work !!!

[bwanasonic]

It's liveable as is but sound like a fender with the bright switch on

That's a feature, not a bug! 

Kerry M

Hey! Avatars?! I just noticed that!

[Melanhead]

How's the volume knob on your guitar set up? Mine has a .001 cap across it so that it retains high end (i.e. gets thinner) on the way down. This is very useful for getting clean clean tones out of an amp, but it could cause the sort of brittleness you're talking about in conjunction with your pedal. Removing such a cap would make the tone a little darker as the volume decreases, or there's a schematic up at fralinpickups.com to have your tone stay the same all the way down.

Maybe it'll help you to attack it from a different angle.

PS you want to roll of the volume to clean it up? or just for volume difference? playing much softer works well with that sort of fuzz.
-
k

No cap yet but wanna put one in ... just too lazy to take the strings off, and never thinking about it when the strings are off

Couldn't find tat schematic at the fralin site, can you point me too it ??

[Melanhead]

I built a fuzz face based on the 70's schematic, too, and I found it too bright as well, so I raised the value of the cap between the two transistors' collector to 47pf, and changed the volume pot to 500k to retain more bass.
Now I'm happy with it when playing at home, but I still haven't tried it at full volumes.
I hope this helps, bye!

Giulio

I currently have a 47pf cap in there but haven't tried the 500k pot, The only thing is that I took a while to fine-tune the amount of bass so I'm not sure if I wanna add more to compensate ... but who knows

[Melanhead]

the other night I built a most wicked Antiquity using 2N2924's (Ge PNP) and  implemented top-end roll off using a 100kB pot and 0.047uF cap between collector of the last device and -9v rail ... try that out 

btw, thx Joe - inspiring work !!!

interesting ... I was also thinking of trying Mark's "Stupidly Wonderful Tone Control" ... an thoughts ?

[Melanhead]

It's liveable as is but sound like a fender with the bright switch on

That's a feature, not a bug! 

Kerry M

Hey! Avatars?! I just noticed that!

cool,  huh !

[MartyMart]

I had a similar problem with an RM "Classic FF" ( rocket enclosure )
I think that I ended up using two roll off caps, a 10n right at the input from
jack to ground and a 3n3 to ground before the last cap on the board.
It worked a treat, smoothed it out, got rid of the "high hash" that was going
on.
Worth a try, but as always, it depends so much on your playing/gtr/amp
so it wont be right for everyone's taste !!

Cheers,
Marty.

[Melanhead]

I had a similar problem with an RM "Classic FF" ( rocket enclosure )
I think that I ended up using two roll off caps, a 10n right at the input from
jack to ground and a 3n3 to ground before the last cap on the board.
It worked a treat, smoothed it out, got rid of the "high hash" that was going
on.
Worth a try, but as always, it depends so much on your playing/gtr/amp
so it wont be right for everyone's taste !!

Cheers,
Marty.

True ...Cool, another idea! ... well lots to do this weekend

[petemoore]

   Fine tuning FF's is an in depth venture.
  Guitar pickups
  guitar vol pot
  Transistors
  Input bass rolloff cap
  another cap somewhere to rolloff bass
  The interaction between the 470 ohm resistor, the output volume, the volume and settings on the amp...a 'standard FF' volume control can take a little hash out when turned down.
  HF Rolloff caps can be added in numerous positions
  I like my FF's a bit darker, and also like the .001uf [or so] cap on the guitar volume.
  An adjustable HF rolloff at the output is another nice thing I've used and like.
  I have 4 FF.

[Melanhead]

   Fine tuning FF's is an in depth venture.
  Guitar pickups
  guitar vol pot
  Transistors
  Input bass rolloff cap
  another cap somewhere to rolloff bass
  The interaction between the 470 ohm resistor, the output volume, the volume and settings on the amp...a 'standard FF' volume control can take a little hash out when turned down.
  HF Rolloff caps can be added in numerous positions
  I like my FF's a bit darker, and also like the .001uf [or so] cap on the guitar volume.
  An adjustable HF rolloff at the output is another nice thing I've used and like.
  I have 4 FF.

I'm beginning to see why this is such an interesting and tweakable circuit ! ..