Hybrid Fuzz Face - stability?

[kwtsos]

Hi everyone, great forum!

I am about to build a Fuzz Face. I mostly like the tone of the germanium ones but I really dont wanna have the stability issues with temperature, you know, hot days, gigs under the sun, etc..

If I build a hybrid one (Q1-silicon, Q2-germanium), will it be stable enough? If not, can I use the "reverse-bias germanium diode" to stabilise my germanium transistor?

All in all, I need a really stable Fuzz with at least one germanium transistor.. Is hybrid the solution?

Thank you guys!

[Johan]

Both your ideas are valid and has ben tried before.do a forum search for easy face
J

[joegagan]

if you have a good germ, the easyface recipe will give you pretty good stability.

[mac]

The problematic transistor is Q1.
Q2 gain and leakage has little impact on thermal runaway. You can use a leaky AC1xx at Q2.
If you want a silicon with high internal capacitance and low gain try BD175 or BD237.

mac

[midwayfair]

These are awesome in Q1:
http://www.smallbearelec.com/servlet/Detail?no=1263

They also work great as Q2 in buzzarounds and benders.

I use a hybrid fuzzface on my board; it's very, very stable.

[joegagan]

midway, are you using an NPN germ for Q2?
the 2n5134 looks pretty but i think it is NPN, right?

[LucifersTrip]

if you use silicon Q1 and one of those "zero" leakage ge modern Russian's (1T308, etc) for Q2, it'll be pretty damn stable for a hybrid FF...but, those Russians won't give you the "softness" that other ge's can

[mac]

if you use silicon Q1 and one of those "zero" leakage ge modern Russian's (1T308, etc) for Q2, it'll be pretty damn stable for a hybrid FF...but, those Russians won't give you the "softness" that other ge's can

If they are zero leakage, go for a Ge FF

mac

[LucifersTrip]

I put "zero" in quotes because they are not really zero leakage. They measure 0 on the Peak Atalas. in reality, they are very low, usually 50uA and under.

[mac]

I have some Toshibas 2sb49/52/53 that leak less than 20ua.
They are too bright for a FF IMHO, but they are less sensitive to temp changes. IIRC they move between 4.0v(winter) and 5.5v(summer).

mac