Need advice to create my own fuzz

[Mattt]

Hi everyone ! I'm building my very own fuzz pedal.
If I know how to analyse circuits I have never managed to create one on my own.
Here is my beta schematic :

there are for the moment 2 stages:
* the first one just amplifie the signal
* the second one use the saturation of the transistor to cut the signal

here is a graphic showing the progress of the signal:


The gain can be changed using R1. I didn't put a tone and volume control yet.

I've tested this schematics and well ... it's a distortion but not what I wanted. Have you got any advice to give to improve the circuit (also about the kind of components ?).

Every critic is welcome.

[Michael Bean]

Hi Mattt,
Your attachments didn't work, yuo might want to try agian. In the mean time check this out.

tonepad -- fx projects

I personally was fond of the sound of the "Tube Sound Fuzz" toward the bottom of the list, also there is a "Fuzz Face" clone if youre into something with more pronounced distortion.

Mike

[geraldfryjr]

Here are a few more links. jer

http://www.diyaudio.com/forums/music...ml#post2630024

[Mattt]

Sorry for the pictures, here they are:



I wanted to do this kind of stuff for a long time and I've already checked a lot of info on the web and magazines, what I really need now is advices from people who know. All the documents I've read have anwsered but also lift many question.

I've seen your links, thanks , tonepad seems to be a great way to find schematics, in the same spirit I knew http://www.diyguitarist.com/DIYStomp...Stompboxes.htm

[chrispenycate]

I wouldn't do it that way. Your biassing is totally dependent on the gain of the transistors (wouldn't you at least like to put in some emitter resistors?), which means the clipping is unlikely to be symmetrical, and the input is virtual earth, low impedance, unsuitable as far as I'm concerned for guitar pickups. R13 is doing nothing, and putting a 680Ω resistor in the collector of Q5 (hello, what happened to 2,3 & 4?) means it can drive lowish impedances – not common in guitar circuits – but will flatten batteries in no time.

Mind you, I agree it will distort.

[Mattt]

Originally Posted by chrispenycate

I wouldn't do it that way. Your biassing is totally dependent on the gain of the transistors (wouldn't you at least like to put in some emitter resistors?), which means the clipping is unlikely to be symmetrical, and the input is virtual earth, low impedance, unsuitable as far as I'm concerned for guitar pickups. R13 is doing nothing, and putting a 680Ω resistor in the collector of Q5 (hello, what happened to 2,3 & 4?) means it can drive lowish impedances – not common in guitar circuits – but will flatten batteries in no time.

Mind you, I agree it will distort.

Thank you for your feedback. he first transistor is in an common emitter disposition to have an optimal amplification, the input impedance is in fact improve by a 1MOhm resistance from Vin to the ground.
R13, well ... the idea was to put the transistor Q5 in a saturation mode. So I needed to have a low tension between the emitter and collector. But you're right it's useless.

I've try to upgrade the old scheme and that's what have now :



I tried to fixe the symmetri problem whith D1, I changed the names and get rid of R13. I have strange results . What do you think ?

[Mattt]

I've made some upgrades :





I fixed the shity common emitter and the polarisation of the two transistors. Any advices for the transistor and diode ? (I thought to use germanium)

[Jarno]

Hi Matt,

You might also want to check Geofex "Technology of the Fuzz Face" a very in depth article on the inner workings of the Fuzz Face fuzz, also discussing components etc.
If you want to look beyond the two transistor circuits, there's a lot of discussion on Big Muff circuit variants to be found on the net.

On top of all this there's FuzzCentral, it seems that it's no longer updated, so it could go down anytime, but a wealth of information too, also on things like the Ampeg Scrambler, which is also a very nice fuzzy-esque pedal.

[Mattt]

Thank you a lot Jarno ! "Technology of the Fuzz Face" seems to be a real wealth of information , exactly what I needed.

This morning I've improve my scheme again :







As you can see I've fixed the common emitter stage and the polarisation of the two transistors. I will read the info you gave me this afternoon and see what I'm going to change but for the moment I'm quite satisfied .

[Mattt]

sorry for the two messages I thought the first time didn't work so I reposted it ... ... ...