This fuzz looks like a joke. But it's not.

[Paul Marossy]

I figure that the low operating point is working its magic and inhibiting the transistor's potential hFE.

Hmm... very interesting finding. Looks like a fun circuit to experiment with.

The results indicate how much this circuit compresses the signal.  For a 500% increase in input (20mV to 100mV), the output only increases by 30% (from 1.7 V p-p to 2.2 V p-p).  But the shape changes from mild single-sided clipping to heavy double-sided clipping.

Got a soundclip? It would be interesting to hear how that happens. Gee, I guess I could build it, huh? It ought take like ten minutes to whip it up... 

[mac]

I´ll try it. Looks promising. I´ll plan to use some high gain Ge as Q1, and PNP/NPN Ge or Si as Q2. Maybe a 3dr tranny after Q2.

It is funny to see how the most easy projects, or at least with less parts, are the ones many people here like the most...

mac

[soggybag]

Would a Ge transistor work well for Q2? I have a few that are not suitable for other uses, either too leaky or too low hfe, maybe this would be a good use.

[mac]

I estimated that for a BD139 hfe around 200, Vc=1.00v & Vb=0.6v.
A Ge hfe near 100, not leaky, will give Vc=1.00v & Vb=0.2v
Current is less than 0.1mA, a battery will last a long time.


mac

[vanessa]

Would a Ge transistor work well for Q2? I have a few that are not suitable for other uses, either too leaky or too low hfe, maybe this would be a good use.

It should work just fine. It should give a different type of clip tone much like trying out different diode types (ge, si, LED) in a circuit like the Distortion + or OD250.

Oh, I forgot it would have to be an NPN ge to make it work.

[birt]

Would a Ge transistor work well for Q2? I have a few that are not suitable for other uses, either too leaky or too low hfe, maybe this would be a good use.

It should work just fine. It should give a different type of clip tone much like trying out different diode types (ge, si, LED) in a circuit like the Distortion + or OD250.

Oh, I forgot it would have to be an NPN ge to make it work.

why does it have to be NPN? jack mentioned earlier only one half of the NPN gets used. so you can use one half of a PNP just as well but connect it the other way around.

[phaeton]

I´ll try it. Looks promising. I´ll plan to use some high gain Ge as Q1, and PNP/NPN Ge or Si as Q2. Maybe a 3dr tranny after Q2.

It is funny to see how the most easy projects, or at least with less parts, are the ones many people here like the most...

mac

True.  I really like the massively simple circuits.  Don't know why.  It's not like I'm afraid of the big'uns, but these little things are a real kick in the pants. Lofi mofo, garagefuzz, bazzfuss, joe's easydrive.  Great stuff!

I also really dig seeing the Silly Scope output on this.  What a treat!  If anyone's got a page of them i'd be very happy wiht a link to it

[KerryF]

Here, I just created a veroboard layout.  Its unverified, but I figured it was easy enough...



I will breadboard it tomarrow and let you all know.  Maybe give some soundclips if it works good.

Just VERIFIED it on the breadboard and it works.  Im still in the process of finding cool mods.

[brett]

Hi again
thanks for the positive feedback.

The Germanium transistor idea is cool.  For 2 x PNP Ge, all you need to do is use positive gound (+9V) and reverse the orientation of the caps.  
But would it sound better?  Hard to tell.  In theory, Ge might be a bit fuzzier due to the lower clipping threshold, and should be a bit more asymetric.  (-ve clipping threshold would be 0.3V (0.7V in PNP Si), while the +ve cutoff should almost as large as an Si version).  But does it need to be more asymetric? 

Also, I wonder how many Ge devices are around that have enough hFE for the first transistor?  Especially under these conditions, where hFE is greatly reduced (Ib = 1uA).  The 2N2222A that I used had hFE of 250 on my DMM, but an AC gain in this circuit of only 100.  My (wild) guess is that suitable Ge transistors need a hFE of at least 150, and preferably 200  (using RG's tester).

Overall, I think people will find the circuit sounds very vintage to start with.

cheers

[petesguitar1]

Even though I don't understand 90% of what goes on on this forum (com[plete neanderthal guitar player!) I'm going to have a crack at this one!

[KerryF]

The only thing I found wrong with this pedal is that it doesnt have good sustain at all.  Is there any way to get more sustain out of it?  Any mods?

[brett]

Hi
I found that is circuit worked better with single coils than humbuckers (a bit like the fuzzface).  Maybe the input impedance is too low.
Try a 10k ohm resistor in series with the input, or a 50k pot wired as a variable resistor, as used in the "boutique" fuzzface. 
That might help reduce and control the loading on the pickups.
cheers

[phaeton]

I breadboarded one just like the diagram.  I don't have hfe measurement on my DVOM so I couldn't tell you where my transistors are at.  They're the metal can 2N222A types.

Interestingly though, in my case about 95% of the clipping happens at Q1.  If i pull Q2 out of the circuit in mid-sustain you *barely* notice a difference, if even at all.  I think all that it might do is attenuate a tad of the top end.  I don't know if this is a condition of my 2N222As (they've clipped in other circuits where you wouldn't necessarily expect them to) or if I've got really powerful pickups on my guitars.  The 335-ish guitar *does* have a very high output, and it's rather muddy sounding too.  Switching to the Ibanez RG with the humbuckers was a little better.  The center singlecoil tightened it up a little, but it was only barely noticeable.  Halfway into it i reduced both caps to 0.1uF for a little less muddiness, and I like that better, personally.  I might even go a tad smaller.

I was going to try some different transistors for kicks, but I've run out of time (the missus is going to bed now )

All in all though, personal anomalies aside, I like what I ended up with.  It's especially good with full 6-string barre chords- it gives that nice, rounded, pleasant texture that's not shrill, jagged or crumbly.

[phaeton]

I guess I should mention that turning my guitar's volume down will bring Q1 under its distortion threshold, but then it wouldn't have enough amplitude to make Q2 clip anyways.  Just thought I'd add that (since my 'modify' button is missing from the last post.  I take it there's a modify timeout on this forum?)

[brett]

Hi again
RE:

it gives that nice, rounded, pleasant texture that's not shrill, jagged or crumbly.

Yeah, that's what I was chasing, but didn't really expect to get it so easily.  To me, it's a very vintage sound.

I just got my cleaner amp going (blown heater fuse), so I'll record a clip tomorrow if everything goes well.  But I don't think my webspace will accept .mp3s.  Would someone host it for me? 
cheers

[KerryF]

Hi
I found that is circuit worked better with single coils than humbuckers (a bit like the fuzzface).  Maybe the input impedance is too low.
Try a 10k ohm resistor in series with the input, or a 50k pot wired as a variable resistor, as used in the "boutique" fuzzface. 
That might help reduce and control the loading on the pickups.
cheers

Well my PRS has coil tapping so I did it with the coil tapping too and it just wasnt cutting it... I will try some other mods today.

[KerryF]

I breadboarded one just like the diagram.  I don't have hfe measurement on my DVOM so I couldn't tell you where my transistors are at.  They're the metal can 2N222A types.

Interestingly though, in my case about 95% of the clipping happens at Q1.  If i pull Q2 out of the circuit in mid-sustain you *barely* notice a difference, if even at all.  I think all that it might do is attenuate a tad of the top end.  I don't know if this is a condition of my 2N222As (they've clipped in other circuits where you wouldn't necessarily expect them to) or if I've got really powerful pickups on my guitars.  The 335-ish guitar *does* have a very high output, and it's rather muddy sounding too.  Switching to the Ibanez RG with the humbuckers was a little better.  The center singlecoil tightened it up a little, but it was only barely noticeable.  Halfway into it i reduced both caps to 0.1uF for a little less muddiness, and I like that better, personally.  I might even go a tad smaller.

I was going to try some different transistors for kicks, but I've run out of time (the missus is going to bed now )

All in all though, personal anomalies aside, I like what I ended up with.  It's especially good with full 6-string barre chords- it gives that nice, rounded, pleasant texture that's not shrill, jagged or crumbly.

Yea I realised the 2nd transistor didnt do much.  What you can do though, is replace it with a diode (1N914/1N4148) and it thickens up a little bit.  Then if you add a second diode placed in the opposite direction to clip, it's volume drops but has much more distortion/fuzz.  I have tried other transistors in the places, and the change is very minimal.  But I will do some more today.

[phaeton]

Hi again
RE:

it gives that nice, rounded, pleasant texture that's not shrill, jagged or crumbly.

Yeah, that's what I was chasing, but didn't really expect to get it so easily.  To me, it's a very vintage sound.

I just got my cleaner amp going (blown heater fuse), so I'll record a clip tomorrow if everything goes well.  But I don't think my webspace will accept .mp3s.  Would someone host it for me? 
cheers

I'll host your mp3, but I don't see why your webspace place won't let you do it.

Otherwise, yes... it's a very 'vintagey' sound.  For kicks I threw an LPB-2 type booster in front of it and it didn't turn out too bad, but it didn't really help it either.  Gave more distortion of course, but it started getting harsh and very SS-like.  Some filtering might help that frankenstein concoction, but the "No Joke" by itself is actually just fine the way it is.  I don't have a whole lot of scientific study into this, but it seems that lower-gain transistors (2n222 for instance) overdrive or clip more 'pleasantly' than some of the higher-gain ones (2N5089, etc).  Just a hunch, but am I too far off the path there?

I'll have to check my biasing and measure the signal strength coming out of Q1 though.  I'm still intrigued as to why it doesn't seem to greatly forward bias any of Q2's junctions, even though it seems to have a pretty high output (it's very loud as configured).

[WGTP]

This may have been mentioned, but I think you can add a cap in parallel with the 1 meg resistor like a 220-470pf to tame the highs a bit.  Like a BMP.  You could also do this with a MOSFET booster and use a MOSFET for the clipping diode.   

[mac]

Also, I wonder how many Ge devices are around that have enough hFE for the first transistor?  Especially under these conditions, where hFE is greatly reduced (Ib = 1uA).  The 2N2222A that I used had hFE of 250 on my DMM, but an AC gain in this circuit of only 100.  My (wild) guess is that suitable Ge transistors need a hFE of at least 150, and preferably 200  (using RG's tester).

I have some 2sb176, hfe>200, low leakage. I'll try it soon.



mac