YAFF (Drag'N'Fly) gain/sustain/decay questions

[w302nv]

I just built a "clone" of a D*A*M Drag'N'Fly...the thing sounds fantastic except for the amount of fuzz seems to drop abruptly off after a few (~5) seconds of sustain.
Q2 is biased to 5.5v and it sounds great otherwise.
What should I focus my attention on to improve this aspect of the circuit?
If I could get that fixed this will be the best YAFF I have ever heard....
Thanks!

[joegagan]

this circuit has many elements in common with easyface. three possible causes for low sustain:
1. too low gain for q2?

2. i would try a 22uf or 47uf at q2 emitter to ground.

3. after the above, set q2  collector to -4.5 to -5.0 v.

[w302nv]

Thanks for the response Joe.
How low is too low for Q2? I have a number of OC140 all are around 100hfe...I suspected that Q2 gain might be an issue so I swapped in a BC337 (154hfe) and was met with similar results.
Presently my Q1 is @ 151 and my Q2 is @ 100...I will swap the cap and re-bias. Thanks again for the suggestions!

[joegagan]

is that bc337 germanium?

i like gains of around 125-130 for q2.
let us know the results, please

[alex frias]

PLease, Ican't resist for YAFF...

[w302nv]

is that bc337 germanium?

NPN Silicon
http://www.fairchildsemi.com/ds/BC/BC337.pdf

[w302nv]

is that bc337 germanium?

i like gains of around 125-130 for q2.
let us know the results, please

47uF too muddy....waiting on a 22uF cap....will post clips id they turn out ok. Thanks again for the help

[joegagan]

too muddy, huh? gotcha.

let us know the progress.

[w302nv]

It would be nice to have a switch to go between the 47 and the 22uF caps....they both have their own thing with different guitars, and they both sound better than the 10uF to my ears. I ended up leaving the 22uF in mine, and I love it. Thanks for the tips Joe! Its awesome that the DnF is similar to your Easy Face (thats my next build).
If the real thing sounds half as good as my clone does, it is one of the best YAFF on the planet.

Thanks Again!

[azrael]

Q1 is way high. I have this circuit cloned too, and it sounds great. I have a 2N4401 with an hFe of 90. My q2 is 120, also an OC140, coincidentally.

[Gus]

Look at R.G.'s FF write up look for the VOX circuit. 

What is Q1 collector voltage?

Look at my circuit that has been in schematics for years now.

http://www.diystompboxes.com/pedals/gusFuzzFace.gif

[monkeyxx]

Hi,

could someone advise on where to find a schematic or layout for the Drag N Fly?? I'd really like to build one.  is the Jack Orman YAFF fuzz identical or something?

a veroboard layout would be dreamy, but I'm willing to work a little harder if needed, just need some initial direction

Thanks!

[azrael]

No, the YAFF is not identical. You can find layouts at the *other* stompbox forum, for free, I do not feel comfortable posting other people's work here.