increasing output of a fuzzbox

[pinkjimiphoton]

sorry to be so completely retarded, but i'm pretty much completely brain dead after a couple weeks of trying to figure this out...
too much information overload i think, i've found some amazing information here and elsewhere, but man..i'm stumped...

a couple years ago, 2007-ish i bought this cheap diy fuzz kit, some two transistor deal...i think it was made by electronic goldmine, or something...

http://www.elexp.com/kit_2026.htm

can't find the schem anywhere, and i know nada about transistors...somewhere, i have the schematic, or had it...but i've moved a couple times, so...

anyways, when i originally built it, i wired the pot wrong...which actually made for some groovy wack broken distortion sounds!!

ahem...sorry...early morning caffiene is just starting to drip.

i modded it with a simple dpdt stompswitch instead of the slider that came with it, and modded the input jack so i could save the battery.

other than that, it was pretty much stock. it's fuzzy, and responsive to dynamics, not necessarily in a GOOD way, but sometimes bad is good..

but the prob i have is, it just has no real testicular fortitude....it wants to be popeye, but it sounds more like sweetpea..bad analogy, i know...

like...even with the "fuzz" knob cranked, it's really only about unity gain....maybe. maybe even a shade quieter than the bypassed signal.

so my retardedly dumb question is, has anyone built this thing, and can anyone please point me toward a way where i can get just a little more output from the
existing circuit?

alot of questions from a newb, sorry...

i have tried playing with resistor values...including just eliminating a 470 ohm resistor (which helped, but barely) with a jumper, but then when the guitar was turned off i was getting radio broadcasts from mars, and the tone knob on my guitar suddenly becomes backwards...weird...until i'd turn it up.

impedance mismatch somewhere?

tried also a friend's suggestion of running a 100k resistor across the 100k pot...seemed to make it just a little louder, but just barely...

kinda lost here...

any help really appreciated!
peace!

jimi

[Mark Hammer]

Looking at the photo, chances are about 90% that it is a Fuzz Face variant.  The circuit has been copied so many times, you can find it in a great many circuit collections.

Use the FF as a guide and trace out the schematic with the component values.  We can take it from there.  There IS a possibility that the transistors are oriented wrong.

[petemoore]

  Just a guess it's a Fuzz Face:
  Take a look at Fuzz Face [NPN Neg Gnd. ?]
  At GGG or GEO.
  Compare what your board would draw to [make schematic of, or just compare your circuit verify that it is a FF].
  The debugging page is amazing to everyone to follows the instructions contained within.
  The FF transistor voltages measurements is the place to start, to see if the circuit is actually biased, since you messed with the 470 to bump gain up, bias is suspect. The FF should have large amplification factor.

[R.G.]

It is very likely that there is some flaw in the original build or wiring.

[pinkjimiphoton]

thanks guys...i suspected the bias may be an issue, i tried removing resistors and substituting pots so i could try and dial it in, but it didn't seem to really help too much.
would a gut shot be helpful?
i can try to take a pic or two and upload them...

thanks so much for the help, it's sincerely appreciated...

r.g.....if you're THE r.g., i wanna thank you again for helping me mod my crybaby several years ago...it's got sqvack!


be back shortly...thanks so much!

[pinkjimiphoton]

ok, here's some guts....

this is the trace side of the circuit board



this is the circuit side...i don't really know how to do a layout or anything yet, so i'll write the values in that i have...



on the left side, top to bottom, are the following values...

680k

6.7k

1mf@50 v

68k

10k


middle are the two transistors..

on the right

47k (the one i changed to 33k in search of more output)

a non-polarized cap that reads 104z

a yellow brown green resistor (i think...i can't find my glasses)

460 ohm

and another cap that says 102 on it.

the pot is 100k (with that 100k resistor i parallelled across it)

sorry...hope maybe now it'll make more sense a little.


thanks!!!

[petemoore]

  Board looks like you did a nice job flowing the solder, but I can't see if there are no cross-trace connections.
  Looks clean but the DMM can tell for sure if a misconnect is there.
  Best to read teh debugging page, that way the magic reading of electron movement predictions can begin to locate what needs attention and what doesn't.

[pinkjimiphoton]

hi folks. i re-read r.g. keene's technology of fuzz face article, and tried a couple mods on it to bring up the output of the second transistor.
didn't make any real difference, unfortunately...but i did look at my junk box, pretty sure that "102" cap was .1mfd...
so i swapped it out with some green mylar one that was in my junk box...i believe it says 14 mfd on the baggie, but it's hard to tell.
now THAT brought the thing to life some...now the output turned up 1/4 of the way is as loud as it used to be full blast, and it's gotta lot more
tone..not GREAT tone, lol...but it's definitely loud and fuzzy, and seems to work well with the volume pot on my guitar.

i checked the board for shorts, etc, didn't find anything, so i guess that part is ok..

but...(of course) now it's not sustaining as well as it did with the circuit OUT of the box...lol.
figures...guess i'll have to play with the resistors that bias the transistors?

can i blow them up if i don't know what i'm doing?
i remember looking at an old guitar amp once, and cooking stuff just trying to read resistance and voltage.

also...this is probably subjective, but i'll ask...

i tried tieing two red led's together into a diode clipper, and tried putting it in a few places in the circuit.

the place it works best is in parallel with the cap i replaced...
i get an unbelievable searing lead tone, i mean, more distortion than i think i've ever heard with a pronounced
kinda heavy 2nd harmonic....unuseable for chords or even diads, but sick for single notes....

if i were to put that in there, maybe with a switch, would it hurt anything?
it makes the gain go WAY up, i'd guestimate a couple db at least....i don't wanna fry anything after it on my
pedalboard!!!  but i do like the way it sounds...

sorry to ask so many dumb questions here....i really hope to eventually understand this stuff enough to try and build my own
fuzzes, i had pretty good luck with tube amp circuits in the past....but they are ALOT more forgiving i think.

thanks to all in advance!
namaste
jimi

[LucifersTrip]

hi folks. i re-read r.g. keene's technology of fuzz face article, and tried a couple mods on it to bring up the output of the second transistor.
didn't make any real difference, unfortunately...but i did look at my junk box, pretty sure that "102" cap was .1mfd...
so i swapped it out with some green mylar one that was in my junk box...i believe it says 14 mfd on the baggie, but it's hard to tell.
now THAT brought the thing to life some...now the output turned up 1/4 of the way is as loud as it used to be full blast, and it's gotta lot more
tone..not GREAT tone, lol...but it's definitely loud and fuzzy, and seems to work well with the volume pot on my guitar.

i checked the board for shorts, etc, didn't find anything, so i guess that part is ok..

but...(of course) now it's not sustaining as well as it did with the circuit OUT of the box...lol.

by increasing the cap, you've added bass response. I usually get more sustain with more treble, so that makes sense.
you prob lost the most sustain in the high E?

i tried tieing two red led's together into a diode clipper, and tried putting it in a few places in the circuit.

the place it works best is in parallel with the cap i replaced...
i get an unbelievable searing lead tone, i mean, more distortion than i think i've ever heard with a pronounced
kinda heavy 2nd harmonic....unuseable for chords or even diads, but sick for single notes....

if i were to put that in there, maybe with a switch, would it hurt anything?
it makes the gain go WAY up, i'd guestimate a couple db at least....i don't wanna fry anything after it on my
pedalboard!!!  but i do like the way it sounds...

you can always get a good indication if you feel components getting hot, but I doubt you'll have any problems with a diode in parallel
with an existing cap, since you didn't create any new connections or shorts with the power supply.

we really need a schematic to answer detailed questions

why don't you just take the schematic to a standard fuzz face and compare it to yours. drag this schematic into whatever graphics program you have and change the values to get yours, then post it for more help




[/quote]

[pinkjimiphoton]

thanks for the reply...i'll try and open it up tomorrow, and draw up a schematic.
it's not a fuzzface, tho probably relatively close... a ff is like 2 caps and  3 resistors, this one has 7 resistors and 3 caps, 2 i think 2n3904's, but i'm not sure, no idea how to tell one transistor from another one. also, this has only one knob, which is pretty much just a distortion control.

thanks for the good news about the diodes..it's a really sick, "about to blow up" searing sound...i really dig it, so now i won't worry so much about it.

anyways...thanks again, try and get to that tomorrow...gotta gig tomorrow nite, will try out the fuzz and a little overdrive i just built..

a 10 mf cap ===>2n3904---->red led diode or in4007 clipper....sounds pretty good! i was amazed something so simple could sound so good...built on a piece of cardboard..
real high tech!!
lol

peace
jimi