TYOS fuzz version 2.0. Still need some more opinions.

[sir_modulus]

Some one and all to the "Ten Year Old Sandwich" rev 2.0 Step right up and see it's crappiness. All critism, comments and suggestions are welcome (you can say it totally sucks if it does, as I want honest opinions here).

Here it is:



Note:

1) CD and Brian Marshall: There will be some minor changes still to come. This is the last version I will put up for critique, and then I post the final thing. I will cut some the bass from each stage. I thank you for your patience.

2) Note this is a big project (4 opamps) so, is it right to do 2 dual OA (for easier PCB layouts), or should I join them into one quad, or do four 741's?

Thanks, all of you, for helping.

[David]

Hey, that isn't crappy at all!  Looks like a very nice piece of work, in fact.  I'd vote for using TL072s for the op-amps.  Maybe a TL074 if you can make the wire paths work to minimize chip count.

[sir_modulus]

Hey, thanks a bunch! Wow! Someone actually thinks it's good!

Sure I'll try the TL074, as long as I can fit it in the layout. BTW (someone asked: TYOS is just a test name. I'll also take suggestions).

[petemoore]

With all the clipping in there...
 Edward Scissorhands @@@

[sir_modulus]

wow your right...ten clipping diodes. It'll be real harsh with the Dirt switch on as, there are four different types that you'll hear clipping at different times.

[MartyMart]

That looks great sir_ !
I'd say stick with 2 dual O/A's  should be neat enough on the board.
Can't wait to try your finished version

Regards,
Marty.

[toneman]

instead of "sandwiching" the fuzzes in series,
why not in parallel, each with their own tone controls??
or add 3 mixer knobs and use existing tonecontrols.
Similar 2 the DoubleD but that was overdrive, this is fuzz.
This could B called the "TripleF".....
Have U had *your* fuzz 2day??
no carbs, no calories, no protein.
staytuned
tone

[David]

wow your right...ten clipping diodes. It'll be real harsh with the Dirt switch on as, there are four different types that you'll hear clipping at different times.

Hey, here's another idea:  Why don't you make it so the soft-clip diodes can be switched in or out for each stage?  That way you control the dirt acquisition as the signal progresses.

Oh, and as to names, since you have 4 op-amps you could call it...

Four Wheel Overdrive!   :mrgreen:

...I'll get me coat... :wink:

[sir_modulus]

Parallel is for a different fuzz (top-secret....well not really). That you'll hear about soon. I will put in switches. I'm currently setting up the PCB, so i'll make it so that you can progresivley clip.

[stm]

Hi, here are my comments:

1) I would AC couple all stages.  This will take control of offset voltages (which can be overamplified), and also reduce some of the lows to give more clarity.

2) You should use a current limiting resistor (1k - 10k) beween the OpAmps and the "dirt" clipping diodes, otherwise you will be overloading, i.e. shorting to ground, the opamps outputs (and this will increase overall current consumption).

3) The three-band tone control you chose is not one of my favorites, as its band frequencies are not well suited for guitar, and they interact a lot.  I would rather throw in a marshall or fender tonestack instead.

4) As you can see on most ROG amp emultors and also in BSIAB II, there is a high frequency rolloff stage at the very end of the circuits, to allow tame highs and fizzyness.  I anticipate that you will need to use the treble control down to allow this as it is now.

Finally, i find very interesting your idea, and I'm sure there is a lot of potential there for good tone.  Please don't think I'm pedantic for pointing out my thoughts!     Keep up the good work!

[sir_modulus]

thanks, That's a lot of good advice. I'll add in all of it, except that I don't know how to AC couple stages. Could you explain how to do this?

[The Tone God]

...except that I don't know how to AC couple stages. Could you explain how to do this?

Stick caps in between the opamp stages and remove the bias resistors. Also I would change the 10K bias resistors to say 100K. Less current.

Andrew

[sir_modulus]

I'll stick caps in, but aren't the bias resistors 1M? That's what I put.

[The Tone God]

Doh! I was thinking inverting stages. Put the caps in and keep the 1Ms. I was talking about two 10Ks for the Vr.

Sorry. Busy day in the shop.

Andrew

[brett]

Hi.  Interesting circuit.  
Unless I'm mistaken (and I often am) the first pair of grounded 4001s won't clip anything because they have such a high threshold voltage compared with the 1N34As (or any other Ge transistor).

Also, the output of the first op-amp HAS to be DC de-coupled to prevent DC conduction through the forward-biased diode.  A small cap (0.01uF) on the op-amp output (after the feedback loop) will do.

have fun