Fuzz Face Si BC108A+B : Tone Problem ?

[Gus]

http://www.diystompboxes.com/pedals/tbV829.gif

sometimes the old designs work well

[slacker]

yeah I've got one of those, or the reissue of it. Into a bright amp it'll rip your head off 

[lenwood]

How about trying a treble-bleed cap across the output volume pot?
starting with 200pf.
It still will be brighter at guitar half volume though.

[billou_35]

Thanks Ienwood ! 

I saw this solution on Geofex RG Keen about Roger Mayer Classic Fuzz:
http://www.geofex.com/Article_Folders/fuzzface/fffram.htm

In fact, I got 3 solutions or workaround :

1/ Change output cap to change the cut frequency but won't change the fact that the cut frequency is moving with the guitar volume, it is useful to find the sweet spot at a certain position of guitar volume pot.

2/ Add a treble-bleed cap across the output volume pot of the FF in case I want to lower the volume at FF side without losing any treble.

3/ Change the Volume pot from 500K to 100K as Eric Johnson, it will change the cut frequency in case Volume pot of Fuzz Face is not at Full... and other things that RG Keen describes better than me... 

Thanks to Aron for this Fabulous Forum ! 

[nico13]

Thanks for your answers !   

In fact, you're right Pete, I should replace "real" FF by "magical" one instead means good Hfe, good Biasing, good sounding !   
Thank you sharing this information, it's funny how this lady makes everyone completely mad ! 

In my case, Bias = 4.5V and Hfe = 200 (Q1) & Hfe = 300 (Q2) so makes me think about 2 questions :

1/ Do a major part of the "Magical" Vintage Fuzz Face Si have Hfe like 'Magical" Ge FF means 70-90 for Q1 and 90-120 for Q2 ? I know that everyone has his own taste but I guess, as for the "magic" numbers for Hfe & Bias, there are some reported numbers for this too ?

2/ I like RG Keen way of thinking that leads me to only believe my ears (with their imperfections) and my ears tell me today, the sound I get is Fabulous but that at full volume, I don't have enough treble so as Tcobretti mentioned (Thanks), my solution would be to increase treble to :

* Lower feedback resistor 100K
* Lower Hfe to a more "vintage" range
* Lower input & output caps
* Do nothing, the FF quest is endless... 

What would you do ? To help you, I'd say the sound I tend to have is, as many I guess, Gilmour's sound from Live at Pompei & Eric Johnson. I don't need strictly the same, I just know that my ears like this sound and I'm near today.

Hello Billou,

I also plan to build a silicon fuzz face to nail David Gilmour's sound on the solo to Echoes from Pompeii.
Shall I use the same kind of transistors as you or some with more / less gain? Or maybe order one pair of selected silicon transistors as available on Banzai?