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SolaSound tone bender transistors

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3/28/2000 11:21 PM

SolaSound tone bender transistors

Can anyone give any insight to the transistors used in the solasound tonebender (3 knob). I know it uses 3 PNP germanium transistors but what I'm curious about is the gain of each transistor. I saw on the fulltone site that his soul bender pedal uses three matched germanium transistors. I also noticed that he sells matched pairs of these for fuzz face clones so I emailed him and asked if he would sell a set for the tonebender. He said no, and that the gain on these guys were way different.
Anyone have any clue about the gains for these guys.
Thanks,
jason

3/29/2000 12:08 AM
Cole	FWIW, the best sounding Sola clone I've made was with three 2N527s, with Hfe from 89-112 (lowest gain in first position, highest in the last.) It has a great fuzz sound and cleans up beautifully with the guitar volume knob. Believe it or not, I've had very good results with 2N3906 transistors in the first 2 positions and a 2SB495 (gain 132) in the last position.

3/29/2000 6:54 PM

The first two transistors are a darlington gain stage, and this is not one of the circuits that produces the delicate nuances of germanium distortion. Two PNP silicons (like the 2N3906) will work about as well as germaniums here. The third transistor being germanium is important, as well as the germanium diode across the third transistor's base-emitter.

The gains of all the transistors can be around 100, 80 to 130 maybe, and sound just fine.

3/29/2000 9:17 PM
jason	Thanks RG, Off to tweakville.... jason

3/29/2000 9:47 PM

I've made two of these, a few years apart, but I didn't bother with any transistor selection or substitution, I just picked some AC128's out of the parts box.

hfe's are:

No.1 Q1 = 72, Q2 = 49, Q3 = 77
No.2 Q1 = 148, Q2 = 300+ (hmmm), Q3 = 184

You might not expect it, but both sound identical. Neither one cleans up like a Fuzz Face, but that doesn't bother me.
The second unit has newer AC128's, which are in a different style case to the ones I've used before and seem to be generally higher in gain (notwithstanding leaky ones).

Stuart

3/29/2000 9:25 PM
pHiLtHy	R.G. - Is your email / ISP working OK? Sent you a couple messages inquiring about the availability of TS boards. I know you've had trouble with your ISP in the past so I thought I would try you here. -p

3/30/2000 12:25 AM

Re: SolaSound tone bender transistors

Yup, I'll second the silicon heresy - the one I made with silicon 2N3906s (Motorola brand, FWIW) sounds excellent and is very similar to the 100% Ge one. The choice of the diode on the last transistor has alot more to do with the tone if you're looking to fiddle around. Garden variety 1N34As sound good, I also like 2N5485 FETs setup as diodes for a little more smoothness & sustain.

FYI, there's a site that has a picture of the insides of the Fulltone Soulbender (I don't remember the URL offhand; it's the Japanese site with alot of Dumble amp pics). You can see two transistors with the gain written on top of the transistors, 85 and 110 if I remember correctly.

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