Garage Fuzz

[Doug_H]

I breadboarded the Garage Fuzz last night and must say it is very cute. (And I mean that in a good way... )

I had a few questions for anyone who has built it though. Mine is not quite as loud as the bypassed signal. I tried implementing the 1M variable resistor volume control but it just acted like a tone control, changing the frequency response from real "thin" to real "full". I tried the panic button but with a .1u all it did was whistle while I  heard some gainy fuzz quietly in the background. I did like a .022u in place of that .1u though. It adds gain and sustain and if I built it I might just leave that in all the time.

I experimented with replicating the 1st stg as a 3rd stg to beef up the output level. It seemed to bring it just up to unity gain, but part of the novelty of this circuit is its simplicity. If I need to add another stg it kind of loses its charm, for me.

FWIW I did use metal can 2n2222's. Just looking for confirmation that this is the correct behavior. Otherwise I have a breadboard problem, which wouldn't surprise me. This would be a fun "no-knob" circuit to build in a tiny box with just enough room for the jacks, switch, & battery.

Doug

[Stevo]

Lets see a scheme I am interested too

[Yun]

Lets see a scheme I am interested too

Here ya go:



Although; i remember it haveing 3 transistors 

[Doug_H]

OK, I looked through the archives and found one build report where it was mentioned that this fuzz is very loud. So I must have a wiring problem somewhere. That's good to know.

Doug

[PenPen]

Thanks for the schem. I think I will try building that as well.


One question, it looks like Q2 is hooked up weird, am I reading this right, the collector of Q2 is grounded, and the emitter is hooked to the V+ source? Thats backwards from what I've seen before, can someone confirm this is how to hook that up?

[Paul Marossy]

I tried building that one but never got it to work. I must have done something wrong... 

[Ge_Whiz]

Yes, Q2 is wierd. According to the originator, Q2 is being used as a negative resistance device, which few transistors will do - hence the insistence on the 2N2222.

[phaeton]

Heh... what a coinkydink...

I had just stumbled upon the "garage fuzz" schematic and was going to build it.  Looks like it should be a fun, stinky lil fuzz circuit.  Call me odd, but I like the "crappy" distortions too.   

It's small enough that I might cram a few more "crap" circuits like it in the same enclosure and switch them all in/out with some slide DPDTs.  Just not sure how to sequence it all together yet- if i should set it up so that I can run them ALL AT ONCE FOR TOTAL SONIC  CARNAGE-

MOO HOO HAA HAA!!!!!!

[PenPen]

Yes, Q2 is wierd. According to the originator, Q2 is being used as a negative resistance device, which few transistors will do - hence the insistence on the 2N2222.

Thanks man. I'll have to get some 2N2222's from SmallBear next time I place an order, I just put in an order for some Rat expermentation (don't want to ruin my original yet) along with some parts for a box I'm building for a friend (my first paid commission! No, I'm not selling a copy of anyone's pedal, just a dead simple mute box). I'll have to shelve this and just save the schem for later. I have another friend that will probably be very interested in this pedal, if it sounds as bad as you guys describe.

[Paul Marossy]

My 2N2222s apparently didn't want to cooperate. 

[PenPen]

My 2N2222s apparently didn't want to cooperate. 

Did you get your 2N2222s from SmallBear or elsewhere?

I'm really a novice at modding, but could you try reducing the value of the Q1 collector resistor from 47k to maybe 10k to increase the output of the first gain stage? I know you usually do this to the second stage, but given that Q2 isn't operating as a normal (ie, FF) second stage amp, perhaps increasing the power on the first stage will boost the output a bit. Maybe its a dumb idea, I'd try it myself if I had the parts before embarrassing myself, but that was one of the first things that came to mind (after the unthinkable idea of removing one of the clipping diodes, or adding a second pair in series with the ones there. May lose some of the cool clipping though).

[Doug_H]

Make sure you use the motorola metal-can 2n2222's, not the plastic ones. Mine is giving me the stinky fuzz sound in the clip, just not loud enough. I suspect wiring issues and am about to try it again.

Doug

[toneman]

U know, It might B good to mention what the beta is of the tranny U used.
2N2222 trannys vary all over the place for beta/gain.
I've seen some 60, others 100, others 150.
Not many over 150, though.
Beta isn't a *universal* measurement, but it would help to get in the ballpark.
Biasing is everything....j.ust look a the FuzzFace history... ;-)
Beta & biasing go together.
May all your trannys B in the ballpark.
Heh heh, do *your* trannys have balls??
heh heh
staybiased
tone

[Paul Marossy]

Did you get your 2N2222s from SmallBear or elsewhere?

I have some that were given to me, and they are the metal can type. Maybe I have a mistake on my PCB layout or something... 

[col]

I built one off the stripboard layout (can't remember whos, might have been Torchy's!) and it worked fine with the 2N2222s, I tried it with some others and it didn't work just as the instructions said it wouldn't. It did work very quietly with BC107s. With the 2N2222 s it was very loud. 2N2222As didn't work well either!

[Doug_H]

With the 2N2222 s it was very loud. 2N2222As didn't work well either!

Well maybe that's the trick. I think mine are 2n2222As. I've moved on to other stuff. I have something of my own that sounds nasty enough for me.

Thanks for the data, though. I may try it again some day if I get my hands on a real 2n2222.

Doug

[Paul Marossy]

I guess I'll have to go back and see just which version of 2N2222 I have...

[PenPen]

With the 2N2222 s it was very loud. 2N2222As didn't work well either!

Well maybe that's the trick. I think mine are 2n2222As. I've moved on to other stuff. I have something of my own that sounds nasty enough for me.

Thanks for the data, though. I may try it again some day if I get my hands on a real 2n2222.

Doug

Doug,

Before taking it apart, check out this http://www.centralsemi.com/leadedpdf/PN2221-2222A.PDF datasheet. The 2N2222A appears to differ in that it needs higher collector/base voltage. Have you tried upping the voltage to either stage of it?

I'm really hoping this can work out, I can't find true 2N2222's at mouser in stock, and smallbear only has the 2N2222A's. If you don't want to mess with it, that cool, I'm going to order some 2N2222A's from smallbear in my next order and give it a go. I'll post results if I can make it work.

[johngreene]

I guess the key would be to insure that the 'negistor' is operating in 'tunnel mode'. Meaning, it should be drawing current. By varying the supply voltage you should see a change of the voltage at the junction of the emitter and the 2.2k resistor. If it's sitting at the supply rail, it's not running in negistor mode. Your particular 2n2222(a)s may require a larger voltage to start working. The key word there is 'start'. As you need to reach the breakdown voltage to get the thing started before it settles back into negistor-land.

--john

[Paul Marossy]

The 2N2222A appears to differ in that it needs higher collector/base voltage. Have you tried upping the voltage to either stage of it?

Got a variable power supply? It would be really easy to dial it up until you got some action. Then you could measure the supply voltage and go from there.