Switching between two transistors

tiges_ tendres · November 22, 2005, 04:59:45 PM

After messing around with my range master for a while today, It occured to me that whilst the ac128 germanium sounded awesome as a boost, dropping in a silicon 2n2907a added a whole new dimension. More drive, and way louder.

My question is would I be able to switch between the two transistors using a dpdt or even a 3pdt switch? Ive figured out how to change the input caps using those switches, but changing transistors has me stumped.

any clues are much appreciated.

JimRayden · November 22, 2005, 05:03:36 PM

Leave one of the pins connected and switch the two other like you would switch a cap.

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Jimbo

jmusser · November 22, 2005, 05:41:21 PM

I can send you a littl hand drawn sketch of how I did it for the Easy Drive if you want it. I liked both the OC140 and the 2N5089 in there, so I wanted a way to switch it.

jmusser · November 22, 2005, 05:42:14 PM

Oh, you'll have to send me your E Mail address.

R.G. · November 22, 2005, 05:54:01 PM

As trivial as that circuit is, why not build one of each and switch between them. That can only take one DPDT maximum. That would also let you tweak each for best sound.

tiges_ tendres · November 23, 2005, 01:09:05 AM

Quote from: R.G. on November 22, 2005, 05:54:01 PM
As trivial as that circuit is, why not build one of each and switch between them. That can only take one DPDT maximum. That would also let you tweak each for best sound.

That is another awesome solution! Although with my tweaking skills running rampant, i can see this pedal with two varitone switches, and about 8 LED's!

Dragonfly · November 23, 2005, 01:32:44 AM

untested, but should work fine....just make sure the orientation of the switch is correct.

rock.twang.good.

Dragonfly · November 23, 2005, 01:38:34 AM

this might be easier to understand...top row goes to one tranny, bottom to the other...the middle row goes to the circuit board where the base, collector, and emmiter of the tranny would normally connect....

tiges_ tendres · November 23, 2005, 01:44:22 AM

Quote from: Dragonfly on November 23, 2005, 01:38:34 AM
this might be easier to understand...top row goes to one tranny, bottom to the other...the middle row goes to the circuit board where the base, collector, and emmiter of the tranny would normally connect....

Now why didn't I think of that? once i get some new 3pdt switches in, I am going to try that! thankyou !

Khas Evets · November 23, 2005, 05:21:46 AM

As Jim said above, you can accomplish this with just a DPDT switch and hard wire the emmitters.

gez · November 23, 2005, 05:40:11 AM

Surely there's a great big clunk when you do the switching?! Personally, I'd take RG's approach...

Peter Snowberg · November 23, 2005, 10:33:55 AM

Keep in mind that the bias WILL be wrong for one of the transistors if you just switch transistors.

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Switching between two transistors