FUZZ FACE GUITAR VOLUME PROBLEM

[grani79]

I built a fuzz face. I used germanium transistor from Small Bear. I changed the resistor values with the same that were in the paper from Small Bearl. Everything seems to work but when I turn off the volume pot of my guitar (0 volume) and the fuzz pot of the fuzz face is at maximum, I ear a strange noise from my amps! What is that???

[Ge_Whiz]

Either radio interference (short wave, VHF, TV line buzz) or some other electrical interence (fluorescent lights, dimmers etc.). A classic Fuzz Face 'feature'.

[grani79]

it's omething like a sound! like a BUZZ ! From 0 to 2 of my volume (in the guitar) I hear a Buzz that change the tonality... then after two everything it seems to be o.k.! No noise! only fuzz

[Chris R]

mine does the same thing... i don't really know how to fix it.  It only happens when my fuzz pot is cranked more than 12 o'clock.. and my guitar volume is down.

mine is pnp, - ground

if anyone has any ideas.. i'd love to hear them.

Chris R

[grani79]

also my is pnp (2n1305 transistor) and negative ground!!!

[Brett Clark]

try this: (not guaranteed, but may help)

First make sure that your input capacitor is in correctly (with the negative side towards the input jack for a PNP negative ground) - of course, if you're using a film cap, this doesn't apply

between the input capacitor and Q1, insert a 2.2K (or something close to that) resistor

between the base of Q1 and ground, add a 100pf capacitor
and another 100pf cap in parallel with the feedback resistor (usually 100K)

these values probably aren't critical - a 10K and 47pf is just as likely to work

alternatively, try a 100pf cap between the base and collector of Q1 and/or Q2

Why is this happening? Your circuit is oscillating at high frequency. Well, the original FF's were known for being noisy and inconsistent, so don't feel bad. The 2N1302 (although it's Germanium) has much more high frequency capability (fT = 25 Mhz) than the Ge transistors usually used in FF's, so you may need to use some of these tricks normally used for Silicon transistors.

[grani79]

I place a 10 k resistor between the input cap and Q1! Now it works good! I tryed 2.2 no way... 4.4 no way... 8.2 no way.... 10 is ok!

THANKS

[Chris R]

thanks brett.. i'll check when i get home.

C

[grani79]

mmmmmm i think that i loose some gain with this mod....

[bwanasonic]

It only happens when my fuzz pot is cranked more than 12 o'clock..

Does anybody actually turn this knob down from full?  

Kerry M

[gez]

Does anybody actually turn this knob down from full?  

Only to check if your ears still work!

[Chris R]

so i added .0047 uf ceramic caps between base & collector of both Q1 and Q2... and this eliminated some of the noise w/ guitar vol at 0... but not all.. so i'll probably try the other suggestions next.

if worse comes to worse.. i'll just deal with it... who turns their guitar volume down to 0 anyways?... right ?

C

[petemoore]

Trimpot [that's how it's int he board on mine] at signal's input...good place to have a pot on a FF...

[1wahfreak]

I had the exact same problem. Strange noises when my guitar volume was down and the fuzz maxed out. I tried a larger input cap and it still didn't work. I finally switched to + ground and every noise and problem went away.

[Chris R]

I just converted to + ground.. and like 1wahfreak said.. all the noise went away.. thanks!!

mmm.. creamy.. i love this.. i've been jamming for a couple hours now ;p

grani79, you should convert yours to positive ground..  its very simple

check here for details: http://www.generalguitargadgets.com/v2/index.php?option=displaypage&Itemid=77&op=page&SubMenu=

Thanks everyone & GGG

C