Adding clipping diodes to a clean boost

[Beros]

Hi

I want to add some clipping diodes and tone caps to a clean boost.. Would this work?
I want the pot to act as a master volume. Will the caps make the tone less trebly when switched on? I'm thinkin of maybe a 22nF and a 2nF cap.



Also, what diodes are good when using a powerful boost?

[blindsjc]

I think that this project from musique.com can
show you some ideas to make this. This effect
is a clean booster, just the C3, D1 and D2 make
it a overdrive.

http://www.muzique.com/schem/projects.htm
http://www.muzique.com/schem/muff.gif

If you search in the forum will find a lot of comments
about tone mods for this circuit too, changing input
and output caps.

Sorry about my poor english.
Thanks

[ambulancevoice]

putting clipping diodes at the output of a boost will just make a distortion/overdrive
caues the signal is boosted by the boost effect than because the signal is loud, much more will be clipped by the diodes creating a distortion

and i think two diodes rather than four would be enough
specially after a boost
what boost are you planning on using?

[Beros]

putting clipping diodes at the output of a boost will just make a distortion/overdrive
caues the signal is boosted by the boost effect than because the signal is loud, much more will be clipped by the diodes creating a distortion

and i think two diodes rather than four would be enough
specially after a boost
what boost are you planning on using?

I'm planning on using a simple single transistor booster circuit wich I found an ond magazine. Just wanted to know if this was the way to go if I wanted the booster to be an overdrive. The reason for med having four diodes is because I want them to be switchable on and off via a 3-way toggle. (Don't really know how to put those switches in the schematic correctly.) So in that case you can have, lets say symmetrical, (off) and asymmetrical clipping via different diodes. I figured a dpdt 3-way on-off-on toggle would do this...

[Mark Hammer]

I want to add some clipping diodes and tone caps to a clean boost.. Would this work?
I want the pot to act as a master volume. Will the caps make the tone less trebly when switched on? I'm thinkin of maybe a 22nF and a 2nF cap.

The caps will provide a treble-cut but do not do so on their own.  The frequency at which the rolloff begins will depend on the cap value and whatever resistance is in series with them.  The values indicated may yield treble-cut well above what your speakers can reproduce, or well below what permits any sort of viable note definition; it depends in what circuit they are installed in.  (hint, hint.  What circuit they are installed in. )

Also, what diodes are good when using a powerful boost?

That depends on what you call "powerful", what you're feeding it with, and what role you want amp overdrive to have.  The diodes will set a limit on possible output level.  Anything above the absolute level set by the diodes will get clipped off (hence "clipping").  If your "powerful boost" takes a 50mv guitar signal and pumps it up to 500mv (and x10 isn't exactly weak), you'll still be too low to make viable use of LEDs.  If your typical output signal is around 2v, then a set of germanium diodes will get you fuzz but nothing that comes close to simple "grit".

The other thing is that the clipping point your diodes work at or provide also sets the maximum output volume and your existing volume pot will only be able to subtract from that.  Consequently, you'll want to select your diodes based on how much potential output level you want.  If you want more volume so as to drive your amp harder then selecting diodes with a lower clipping threshold will work against you.

One possibility is to use a pair of diodes and a pot to vary how much clipping is permitted with the same set of diodes.  Jack Orman used to have an article on such "warp" circuits over at AMZ but I couldn't find it.  Suffice it to say that you may find what you seek by having a pair of 1N914 or 1N4148 diodes with a 10k variable resistance between their "ground side" and ground.

[Beros]

Ok thanks Mark. In other words a resistor between the diodes and ground will make the circuit louder, and the diodes clip less?
I prefer to keep my booster circuit secret... I guess I'll socket the diodes and try different combos.

[Mark Hammer]

Ok thanks Mark. In other words a resistor between the diodes and ground will make the circuit louder, and the diodes clip less?

Yep, pretty much.  The clipping occurs because the diodes pass signal to ground above a certain level.  The greater the resistance between the diodes and ground, the less signal gets lost.  So, the volume will increase as the clipping is reduced with the suggested circuit change.

For your tone/treble-cut, I'd suggest the SWTC. http://hammer.ampage.org/files/SWTC.gif

[foxfire]

read all of this. there are a ton of good ideas here,http://www.muzique.com/lab/main.htm

[Mark Hammer]

Thanks for that.  Here's what I couldn't find the link to earlier: http://www.muzique.com/lab/warp.htm

[Processaurus]

looks like you could use two spdt center off toggle switches for switching your diode set and cap set.

[soulsonic]

My Fish design is this sort of concept, 'cept it uses a germanium transistor for the clipping.

[cb]

If the distortion you get from adding the clipping diodes sounds too flabby, farty, or just plain muffled try rolling off bass prior to clipping. In most fx circuits, there's usually a capacitor in series with the signal near the input. Making that cap smaller will roll off more bass. Start with say .01uf, then maybe .0047, etc.

[Beros]

You guys really are great! Thanks!