Bass Fuzz... Bass can push.. guitar can't

[Evad Nomenclature]

Hey guys.

Screwing around a few weeks ago, I made the simple bass fuzz (the one from Dragonfly's layout, but there are tons out there)
Since I'm still figuring out the whole electronics thing, can anyone answer me this question?

The Fuzz worked well with bass, nice square wave sounding and thick (very reminiscent to the fuzz sound at the beginning of Muse's Hysteria to me)
When I put the guitar through it, it got a little sound, but it kept cutting out shortly after I hit a note... (almost like it was slowly being gated)

Now I'm assuming this has something to do with active pickups of my bass vs regular single coils on guitar...
But ... why? =) and is there a way to remedy this so it would work with guitar too?

Thanks muchos.
dave

[petemoore]

  You have 2 transistors doing a lot of work for 2 transistors, depending on how strong the input signal is, the circuit will exhibit various behaviours such as described.
  The bass string has 'large' going for it in all contexts including signal strength, add to that 'active' and at the very least you have low impedance, probably substantial boost, compared to 'the guitar' you've noticed a difference in circuit function.
  A Booster...of any sort with an active [ie buffer or voltage gain, ITC of 'the guitar' into the Bazz Fuss, probably an active gain booster] , is very often a good first thing to have [IME] when processing signals, most commercial effects [all with active bypass circuits] boost the signal as a first order of business.
  It's a third transistor, but much less than different guitar or pickups.
  Not that I'm suggesting 'soft' pickups are undesirable in the least, contrary...having 'low' output to start with means there's farther to go before you get to 'high'...ie with electronics 'helping' sometimes that's what allows you to get what you want, from all the way down to 'all' the way up.
  Conversely high output pickups are high output pickups and sound / act like it...different is all.
  Booster is what the Bass pickups have on them, guitar probably really needs that to get it going...
  IIRC that circuit calls for HG Darlington transistora.

[mac]

Try adjusting the collector resistor. BF bias depends a lot on transistor gain.

mac

[Evad Nomenclature]

Thanks for the suggestions,
I'll give it a shot when I have a sec later.

[Mugshot]

upping this thread! built the simple bass fuzz from Dragonfly's vero layout. i used perf. i used 2N3904 trannies for my first bass fuz build. here are my build reports:

1) with the 10K collector bias resistor, it sounds too gated. increasing to 100K-470K helped. i used 100K though. and it was perfect for bass! you can also try a 1Meg linear pot ala-Trotsky gain pot 

2) i built another BF but this time - it was for guitars - i used a 2N5088 tranny. it was a mistake putting in 1N60 diodes, there was no sustain. i put Silicon diodes and all worked well. i changed input and output cap (both 0.47uF) to filter the frequency. big time grinder! i think the 5088 fits better fr guitars than the 3904 does.

wow, what a circuit though!

[Paul Marossy]

it was a mistake putting in 1N60 diodes, there was no sustain. i put Silicon diodes and all worked well.

I have found that I really don't like Ge diodes in anything. I much prefer the Si types, like the 1N4148. Even diodes like 1N4001s sound better, IMO.

[Mugshot]

it was a mistake putting in 1N60 diodes, there was no sustain. i put Silicon diodes and all worked well.

I have found that I really don't like Ge diodes in anything. I much prefer the Si types, like the 1N4148. Even diodes like 1N4001s sound better, IMO.

my sentiments exactly  for some reason i dislike Ge diodes except for some very rare cases.

it was only lately though that i discovered this circuit - easy build, low component number, great tone. actually i have the schematic about a month ago but havent put much interest into building one thinking it was just a regular booster of some sort. i admit im kinda new to reading schematics (this time i definitely am learning more; the transistor emitter biasing to ground for NPN puzzles me. why?  )

now i have a number of unhoused circuits scattered all over my room. i should get a breadboard soon. and that means one thing: finally i AM starting to know circuits more.

and back to the bass fuzz (pardon the novel i posted above  ). i will be building the deluxe version sans the transformer thing tonight! wish me luck! (i know ive been lucky. my soldering skills are getting better and better every night. i love perfboard! best for modding circuits!)

[Paul Marossy]

my sentiments exactly  for some reason i dislike Ge diodes except for some very rare cases.

I'm glad that I'm not the only one!