Found this: http://www.ti.com/lit/ds/symlink/lm833-n.pdf
I guess the op amp doesn't really matter too much.

I couldn't find it after a quick search either.

I have built one out of one of the other data sheets before. But i didn't like it because the mid frequency wasn't ideal for guitar, and i abandoned the bax style stacks concept before i got around to changing the frequencies around.

I don't think the one i built was that LM833 one. But even if you don't like the range of the controls, it is pretty simple to move the frequencies around, they even have the math there for you (frequency in hertz, resistance in ohms, capacitance in farads).

And yeah, the specific opamp won't matter too much. Especially if the data sheet doesn't call for oddly high voltages(not all opamps can handle ±15v for instance) or anything. For running an opamp off 9v/4.5v, it pretty much won't matter, just about all common types will work. Certain chips will be lower noise though obviously.

I got all the standard parts for a titan on a breadboard now. Just need to wire the fucker up. a task for saturday I think.

Really? Thats it? I add in a 1M or 2M2 resistor at the input, a trimmer fro Q2 and a LED + 4.7k and I have a Fuzz Face? Did I miss something? Is there any reason Mammoth's caps and BC108 wouldn't work?

Fuzzfaces are deceptively simple. Yes that is all there is to them though.

Getting the transistors biased properly to sound the best can sometimes be a bit fiddly. I have not put one together yet, that did not require alteration of the bias to function well.

Either breadboard it first with the transistors you are going to use, or if you go straight to building a boxed version, socket the trannies and the 8k2 resistor(or use a 10k-ish trimmer, as you mentioned) at least.

Transistor sockets and a trim pot and I shouldn't have any trouble at all I'll probably place an order on Monday

Ok so its not Monday, but I do haz an order

I haz sound, but I haz no fuzz... (NPN Si transistors)

Q1:
E: 0v
B: 0.5v
C: 1.65v

Q2
E: 1v
B: 1.65v
C: ~4.8v (trimmer sets it between ~1v to ~6.3v)

How are you building, what layout, pictars?

basedish on this layout(with +9 instead of -9 and the caps facing the right way according to the schematic a few post ago) with a resistor and trimmer and LED added. I somehow lost the 330 ohm resistor so I put a couple of ~100+ resistors in series and it got me about 380 ohms (which should be fine).



http://i274.photobucket.com/albums/jj26 ... 151758.jpg

A little messy but everything seems ok

http://i274.photobucket.com/albums/jj26 ... 153009.jpg

The footswitch is wired based on how GGG's does theirs

http://i274.photobucket.com/albums/jj26 ... 151840.jpg

It is difficult for me to follow perfboard, but it almost looks like your trannies might be in backwards?

Also, it looks to me like the layout and schematic are both showing the same orientation for the electrolytics? And that the one off of the fuzz pot lug 2 in your build *might be backwards?


* i say might, because like i said it is a bit more difficult for me to follow perfboards.

The pics are upside down compared to the layout so i guess that might be what was throwing you off with the trannies. (my bad)

I didn't notice the layout had the orientation for the electrolytic caps... Either way, C1's positive goes to Q1's base (middle), negative to the input; C3's positive goes to Fuzz pot's #2 lug and its negative is to ground.

Ah, i can't see the tab, so i assumed that the emitter was the bottom leg on both trannies, and it looked to me like the bias resistors/trimpot were wired up to them.

Also, it looked to me like you had the negative of C3 connected to the fuzz pot wire, which is why i thought it was backwards as well. I guess that wire on the top edge is going to ground somewhere?

yep. top middle wire is the ground. i used the output sleeve lug as a common ground.

So I took my eq and used it as a clean boost and I had fuzz! So something isn't getting enough signal... not sure where to go from here

Worth noting, that this doesn't necessarily mean that the fuzz circuit is 100% right either. Lots of things will give fuzz sounds if fed a heavily boosted signal. Even some broken circuits.

That said, can you adjust the sound of the thing by adjusting the trimpot?

In general in a fuzz that isn't fuzzing:

1. Assuming the build is correct and the resistors are all the right values(like you don't have a 330k instead of the 33k, or a 330k instead of the 330 ohm, or something like that).

2. You probably have a biasing issue. If you can't get it happy with just the one trimpot, you might need to put one in for the 33k too.

Purely out of curiosity, i would perhaps try the transistors in backwards, as sometimes you come across an odd pinout for things. But that is less likely if you are using a well-known type like a BC108. Still, you have them socketed, so it is a very easy test just to rule it out.

You could also try to go for some suggested values from something like the fuzzface calculator here: http://www.diystompboxes.com/analogalchemy/emh/emh.html

Though, in troof, what i ended up with in the fuzzfaces i built was pretty far from what that calculator spat out.

Also: this is why i suggested breadboard as a fine way to put a fuzzface together.

Definitely not 1, I think I have checked everything like 20 times...

Probably 2 While not practical, I do have a few extra resistors I can play with. I'm think I'll start by lowering the 33k to something else...

BTW: Definitely not backwards... I was 99.99% they were right, then i put it backwards and it was bad... now I'm 100% sure

I surrender I'm going to try to find a couple of trimpots locally, if not I'll just place an order on small bear or something...

Unfailz.... Knope haz moar fuzz!!! (trannies were backwards x 100000000000000000000000000000000000000)