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DIY Stompboxes => Building your own stompbox => Topic started by: carrejans on January 29, 2010, 04:40:13 PM

Title: Using a 3PDT to switch between 2 transistors?
Post by: carrejans on January 29, 2010, 04:40:13 PM
Hi guys,

I was thinking, is it possible to switch between 2 different transitors in a circuit with a 3PDT?
Or will there be issues, doing it this way?

Thanks...
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: frequencycentral on January 29, 2010, 05:04:35 PM
I'm pretty sure beavis has done this....................
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: caress on January 29, 2010, 06:57:18 PM
same as doing it with a toggle, only you're stepping on it...
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: tcobretti on January 29, 2010, 11:00:19 PM
I would imagine you'll get some crazy popping, so it may not be appropriate for the gig.
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: jacobyjd on January 29, 2010, 11:03:01 PM
I wouldn't see a whole lot of value in making it a footswitchable parameter. a toggle is a fine idea though.
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: Paul Marossy on January 30, 2010, 02:30:27 PM
I would imagine you'll get some crazy popping, so it may not be appropriate for the gig.

Yeah, that was also my first thought.

I wouldn't see a whole lot of value in making it a footswitchable parameter. a toggle is a fine idea though.

I agree.
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: DaveM on January 30, 2010, 04:07:23 PM
You only need a DPDT to switch between transistors, as you can keep the emitter (or base or collector, i'm not sure it would matter) of the two transistors connected all of the time.  I used a sub-mini toggle for switching, and the is a small pop, but nothing insane.  Here's the schematic of the FuzzFace clone I was switching transistors on.  (http://www.instructables.com/files/orig/FYB/VCK8/FYNTACN7/FYBVCK8FYNTACN7.gif)
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: frank_p on January 30, 2010, 04:17:02 PM

Using a 4pdt may be usefull if your Hfe are differents (you will need two more biasing resistors of different values).
See that topic:
http://www.diystompboxes.com/smfforum/index.php?topic=73259.0
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: Paul Marossy on January 30, 2010, 09:35:28 PM
I guess a small pop upon switching isn't too bad.
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: devi ever on January 30, 2010, 10:44:15 PM
I guess a small pop upon switching isn't too bad.

Yeah... depends on the circuit and setup as well.
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: carrejans on February 01, 2010, 06:12:20 PM
I wouldn't see a whole lot of value in making it a footswitchable parameter. a toggle is a fine idea though.
I agree.

Where did I mention that I want to use a footswitch?  ???

Thanks for the answers. Indeed a 4pdt is even better. Thanks for that idea!!!
Title: Re: Using a 3PDT to switch between 2 transistors?
Post by: caress on February 01, 2010, 09:53:08 PM
Where did I mention that I want to use a footswitch?  ???

lol not sure why i thought that!  sorry...   :D