Barber LTD tone control

[mmaatt25]

Hi,

I built a Barber LTD silver version a year ago from the layout in the gallery here http://www.aronnelson.com/gallery/main.php/v/Xaviers-shrine-of-noise/Layouts/SilverLTD.gif.html
I love this overdrive pedal, as rhythm player I find this has enough overdrive whilst still being able to here the chords etc I'm playing.

I find the tone control really subtle, to the point I can only just here a change between min and max tone? I've played with internal trim pots and the only one I can really hear make a difference is the mid trimmer.
Has anyone else any experience with this circuit?

Has anyone got any PCB for this or could they etch me one, I've made mine on perfboard, but as I know this pedal is a keeper it would be nice to have it on a nice board.

And I'd just like to thank David Barber for sharing this circuit with us. It goes a way to restoring my faith in this selfish, greedy world.

Thanks

Matt

[Mark Hammer]

The .01uf/150k and 1k8/.02uf networks yield considerable overlap in their passbands, when compared to something like a Big Muff.

Consider:

• the .01uf/150k network provides a highpass function, starting around 106hz
• the 1k8/.02uf network provides a lowpass function, starting around 4420hz
• the Big Muff's 39k/.01uf network provides a lowpass function, starting around 408hz
• the Big Muff's 4000pf/39k network provides a high pass function starting around 1020hz

Now, I fully realize, there are a bazillion variations on the BMP tonestack values, but one of the things they all share in common is that there is minimal overlap between what you get when you pan the tone control fully in one direction.  And that is because the corner frequencies of the high and low sections leading up to the tone control are staggered to leave a zone in the middle unspoken for.  In the case of the SilverLTD, the bassbands overlap a LOT (assuming the posted component values are correct).  I mean, there isn't much guitar signal outside of 106hz - 4.4khz, and both filter sections contain that.  So, it would seem the simplest fix is to space the corner frequencies of the two sections differently.

I won't present this as gospel, but consider changing the .02uf cap for a .047uf cap on the bass side, and the .01uf cap for a .001uf cap on the treble side.  That will move your bass corner frequency to just under 1.9khz and your treble to 1060hz.  That shold give a rounded "throaty" tone at full bass, and a more biting tone at full treble, while retaining most of the common middle content at all settings.