Germanium Fuzz Face sound clip--what do you think?

[tehfunk]

Okay, so I built this germanium fuzz face with the transistors I received from any, I had been breadboarding for a while, I just went into it assuming the gains he told me, and put them in the standard circuit and biased them up... I changed the standard 33k Q1 collector resistor to 27k, what exactly does this do to the circuit?? and then used a trim pot to adjust to 4.5 V on Q2 C.
Here are my voltages.

Q1
E: 0 V
B: .122 V
C: .476 V
Q2
E: .336 V
B: .478 V
C: 4.49 V

So what I want to know is, is this what a properly biased germanium fuzz face should sound like--and most importantly, does it sound good? I know it's subjective, but everyone's built their own fuzz faces and I was wondering if this is what you are used to/try to achieve, or could it have some changes to sound better.

Here's the sound clip, recorded with crappy strat knockoff into clean Marshall JCM800. Volume and Fuzz both maxed. Guitar volume starts max, and I slowly decrease it to the point where the transistors almost cut out and then I bring it back up.

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/tehfunk/soundclips/fuzz+face+testing.mp3.html

Any input/help is appreciated, thanks!
-Sam

P.S. this was recorded while the circuit was on the breadboard, and it still is.

[raulgrell]

It doesn't sound right, something is off... Not sure if it's the biasing, but it very well could be... Mess around with it, see what you come up with.

Sounds closer with the volume down a bit, but still off I think...

[petemoore]

  What is the supply voltage these measurements reference to ?

[tehfunk]

  What is the supply voltage these measurements reference to ?

Sorry, but you mean battery voltage right? If so, it was between 9.2 and 9.3 volts.

[tehfunk]

I have to add, the one thing I have actually noticed that could be wrong, and might be the problem, reveal it, or be a result of something else wrong is with the volume control. In watching youtube videos of other fuzz faces, both silicon and germanium, lots of people do not have their volume on full, and it sounds like mine on just about full. For me, if my volume is anywhere below around 9.5 out of 10 it gets really bassy and it doesn't sound right. So, I guess what I am trying to say is that in order to get my circuit to sound like other peoples (tonally, not volume wise) I have to turn it up pretty much all the way; and that "diming" might be what's getting that layer of extra fuzz riding on top of the notes. I don't know, just guessing.

[brett]

Hi
the "nasty" sound is because Q1 isn't properly biased.  The base should be at approximately 0.3V.

FWIW, FFs often sound better and bias better with a 47k feedback resistor than the standard 100k.
have fun

[Focalized]

I've built mostly silicon fuzzes and they usually just need harsh treble taming.


I just built a Germanium from scratch. With that one and most my other silicon ones, when you max the volume the mids and treble seem to get boosted. Into a low volume clean amp that doesn't sound good. Might be better when an amp has more natural drive going. Usually the sound I like is right before that happens. Around 75% with a regular 500k audio pot. If the volume is still too low at that setting, I'll increased R2 to 1k. I did this with my new Germanium and it helped a lot.

I also use reverse audio for both pots. The range is better.

[tehfunk]

Hi
the "nasty" sound is because Q1 isn't properly biased.  The base should be at approximately 0.3V.

FWIW, FFs often sound better and bias better with a 47k feedback resistor than the standard 100k.
have fun

thanks, i'll have to try it, that sounds like it might just do it, do you think it will make the volume pot more like "other" people's? I'm happy it's a kind of definitive fix.

[brett]

Hi
I didn't mean to give the impression that changing the feedback resistor would fix the bias problem.
Both Q1 and Q2 have issues.  Q1 *might* be out because it gets its bias from Q2.  The voltage on the base and emitter of Q2 seems too low (does generalguitargadgets.com have suggested voltages for this?).  I would double-check the values of the collector resistors on Q1 and Q2 and the value of the fuzz pot.
cheers

[tehfunk]

I checked the correct voltages, and just re breadboarded the circuit and got them better, but the base of q1 is supposed to be a little over .1 volts.
here's what I have as correct.
Q1
c: .5   b: .1   e: 0
Q2
c: 4.5 - 5  b. .5 - .6  e: .4

I think it sounds pretty good, I just think it ends up going to a higher "level of fuzz" then others, maybe that's why you said it sounded more right at lower guitar volumes. My volume pot and fuzz pot are both the right values...I still wish I could understand why anything under about 8 or 9 on volume is just unplayable, extremely dark. Though, my unity gain, is at about 10, which is the one thing that seems to be standing out as wrong. What difference does having a 22 uf cap instead of a 20 uf, because that's my only part difference from the original other than the biasing resistors? Any help would be appreciated. I want to get it off the breadboard solder it up and breadboard something else already.    Thanks.
-Sam

[yeeshkul]

I checked the correct voltages, and just re breadboarded the circuit and got them better, but the base of q1 is supposed to be a little over .1 volts.
here's what I have as correct.
Q1
c: .5   b: .1   e: 0
Q2
c: 4.5 - 5  b. .5 - .6  e: .4

I think it sounds pretty good, I just think it ends up going to a higher "level of fuzz" then others, maybe that's why you said it sounded more right at lower guitar volumes. My volume pot and fuzz pot are both the right values...I still wish I could understand why anything under about 8 or 9 on volume is just unplayable, extremely dark. Though, my unity gain, is at about 10, which is the one thing that seems to be standing out as wrong. What difference does having a 22 uf cap instead of a 20 uf, because that's my only part difference from the original other than the biasing resistors? Any help would be appreciated. I want to get it off the breadboard solder it up and breadboard something else already.    Thanks.
-Sam

The base of Q1 should be around -0.5V. There is no tone difference between 20U and 22u fuzz cap, i can hear slight difference when i put "tonebender" 4u7 in. The bias voltage on Q1 base is provided by the feedback 100k res in series with the fuzzpot, so sniff around there. Also try another tranny for Q1.

[tehfunk]

I checked the correct voltages, and just re breadboarded the circuit and got them better, but the base of q1 is supposed to be a little over .1 volts.
here's what I have as correct.
Q1
c: .5   b: .1   e: 0
Q2
c: 4.5 - 5  b. .5 - .6  e: .4

I think it sounds pretty good, I just think it ends up going to a higher "level of fuzz" then others, maybe that's why you said it sounded more right at lower guitar volumes. My volume pot and fuzz pot are both the right values...I still wish I could understand why anything under about 8 or 9 on volume is just unplayable, extremely dark. Though, my unity gain, is at about 10, which is the one thing that seems to be standing out as wrong. What difference does having a 22 uf cap instead of a 20 uf, because that's my only part difference from the original other than the biasing resistors? Any help would be appreciated. I want to get it off the breadboard solder it up and breadboard something else already.    Thanks.
-Sam

The base of Q1 should be around -0.5V. There is no tone difference between 20U and 22u fuzz cap, i can hear slight difference when i put "tonebender" 4u7 in. The bias voltage on Q1 base is provided by the feedback 100k res in series with the fuzzpot, so sniff around there. Also try another tranny for Q1.

GGG says
q1 base should be .1 volts and so do multiple threads on this forum, i am very confused.

[yeeshkul]

Sorry, my wrong guess. i measured my FF and it is- 0.1V. That 0.5V applies for Si FF.

[mac]

Are you still using a 27K? Increase it to 33k or 47k and try again.

BTW, some good sample, look for Greg_V demo
http://analogman.com/fuzzface.htm#samples

mac