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DIY Stompboxes => Building your own stompbox => Topic started by: donald stringer on August 19, 2008, 12:30:05 PM

Title: clipping diodes
Post by: donald stringer on August 19, 2008, 12:30:05 PM
I am finishing up an preamp and was wondering besides the typical clipping diodes, does putting them with there own single op-amp as an mild boost make some since.
Title: Re: clipping diodes
Post by: d95err on August 19, 2008, 03:02:12 PM
I'm not sure what you mean. Could you explain further? (if you can show some kind of schematic of what you're thinking about it will help a lot)
Title: Re: clipping diodes
Post by: Mark Hammer on August 19, 2008, 03:37:42 PM
I think the word "since" was intended to be "sense".

Diodes have a fixed absolute threshold that must be reached by enough of the signal before audible clipping is produced.  So, if the diode clips at 540mv, and even after some boosting the signal only ever exceeds 540mv for a very brief moment at the start of the note, you will NOT hear any clipping.

To determine if there will be some clipping, you need to have a sense of:

a) how much gain you are applying
b) what the clipping threshold of diode/s in question is/are
c) what the original signal is like before the boost

If your diode clips at 1.5v (typical of LEDs), and you have applied a gain of 10x to a signal that rarely goes above 60mv (600mv after the boost), you will not hear much clipping at all.