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DIY Stompboxes => Building your own stompbox => Topic started by: brett on June 03, 2004, 01:27:29 AM

Title: Transistors as clipping diodes (Maestro-style)
Post by: brett on June 03, 2004, 01:27:29 AM
Hi.
The Maestro FZ-1S uses BOTH the base-emitter and base-collector junctions of transistors (Q5 and Q6) in this way.  (At least I *think* that's what they're there for)  Here's the Maestro:http://www.generalguitargadgets.com/v2/diagrams/maessfsc.gif

I am wondering if anybody has tried this and whether the results were different to a 1N4148 or 1N4004 ? I wonder whether both junctions would conduct?

Might be worth trying this in a Jordan Bosstone or other clipping type circuits (Dist +)?  Or is it a waste of time?  Any takers?

thanks
Title: Transistors as clipping diodes (Maestro-style)
Post by: Tim Escobedo on June 03, 2004, 02:10:26 AM
I use transistors that way. I find that generally, transistors clip at a little higher level than a typical Si rectifier diode. Which I think accounts for 95% of the tonal diffrences of any diode clipper. I did some informal testing once and found high hfe transistors clipped at slightly higher levels than low hfe transistors.

I can't tell any significant difference between the b-e junction or the b-c junctions. I almost thought I could in one particular circuit. But even my own anecdotal results weren't repeatable in the end.
Title: Transistors as clipping diodes (Maestro-style)
Post by: Mark Hammer on June 03, 2004, 11:10:17 AM
I'll tell you one good reason why its worth considering using transistors as clipping elements: the hit-to-miss ratio when you buy these things.  I have at least a hundred or more Ge trannies in parts bins at home, and the majority of them are going to end up as poor choices for effects....at least as gain stages.  Used as diodes, though, they may well have some utility left.
Title: Transistors as clipping diodes (Maestro-style)
Post by: WGTP on June 03, 2004, 08:11:02 PM
At Aron's suggestion, I have used Mosfet's and Jfet's with positive results.

The Mosfet's blow easily tho.  Jfets J201 MPF102 are cool.  Different Thresholds than SI or GE. 8)