Tubescreamer Germanium Mod (need help)

[Oliver]

Hi,

i tried to implantate a Germanium Transistor as a Clipping Diode
in my TS Clone.
I took Base and Emitter as described in a Mod i found on the Net.

The sound distorts, but only when strings of Guitar are hidden hard.
It comes like a bad biased FuzzFace.

I tried AC188K and AC128 Transistors, both made the same bad sound.

can anybody tell me, what I am doing wrong??

thanx for Help

ciao
Oliver

[petemoore]

Post them...
 Kinda sounds to me like the problem isnt necessarily with the diodes.
 What;s it sound like with vol and gain turned less than half and the diodes out?

[Oliver]

Post them...
 Kinda sounds to me like the problem isnt necessarily with the diodes.
 What;s it sound like with vol and gain turned less than half and the diodes out?

Hi,

dont have soundsamples, but it sounds slightly farting and gated with
less sustain and i have do play harder to get a normal Sound for a short time. When the Germanium Tranny is replaced by a normal Diode (1N4004, 1N914 or red LED) the Sound is good.

When Gain and or Level is turned down, the sound is more gated. seems, that the Transistor needs more power, but in the Mod description says, that it is used as D6 in the Boss SD-1 (for me its similar to the TS circuit)
the only difference is, that i dont use asymetrical clipping.
may that cause the bad tone? the not added Diode in Serie with the Transistor??  :roll:

thanx
bye
Oliver

[Ge_Whiz]

Could it be a very leaky transistor?

[Oliver]

Hi,

maybe, i tried three AC188 and one AC128 made all the same trouble.
As i measured them, the AC188 are at hfe (435/385 and one is about 83)
the AC128 has a hfe around 172

For the first moment a note sounds very good (agressive and snarling)

At the moment i like one 1N4004 with one red LED antiparallel. but it nerves me, that the Mod with the Germanium Tranny dont work

Ill try an Si Transistor with a higher Gain.

any other ideas?

cu
Oliver

[Oliver]

SUCCESSSSSSSSSSS!!!

HI,

i experimented a bit and get it run! (did i wrote that correct?)

An AC128 (Emitter ->  Base) followed by an 1N4004 and one or better
two 1N4004 in the other Direction works very well.
I Use an 1Meg Pot, a 5K6 Resistor between Pin6 and Pin7 instead of the 1K Stock.. and a 200pF Cap instead the Stock 47pF in the Gainstage.

Thats a real Killersound!!! Much Gain and very clear Overdrive Crunch.

bye
Oliver