Boss DS-1 More linear distortion increase

[fullenglish]

Hi to everyone here.

I have spent a lot of time modding a DS-1 The basis for the mod was Brians Premier Guitar JCM Mod with some Keeley mods as well and then tailored the sound for my needs.  After lots of changes I started to have an understanding of what different component changes made to the sound.

It is now totally awesome, From mild crunch to insane, whist retaining the original frequencies. and the three people that i have demonstrated it to have all asked me to do the mod for them.  My only issue is that the distortion doesn't increase gradually in a linear way. So the searing lead tone that you get happens from 3 o clock on DIST pot to max. I would like to get more distortion around the mid settings on DIST pot and less ramping up at the end.

I have the R13 1k and C8 1.5uF mod to get more distortion and D5 LED. About 20 component changes in total

Does anyone know of any component changes to achieve this ?

Thanks

[bwdavis99]

I think you'd have to change that distortion pot

[fullenglish]

I haven't checked but i think its a linear pot. The R13 / C8 mod gives it more distortion, but only on the last part of pot travel

[diggum12]

You could always try a 250kB pot, but I don't guarantee any success. 

[fullenglish]

I don't really want to mess around with the pots as it would probably require a cap change... I'm guessing. And after many hours researching and numerous component changes, I've got it nearly to how i want it. Maybe Brian knows if there is a resistor change, to increase the distortion at middle settings on DIST pot. Perhaps R11 has something to do with it ?

[diggum12]

Maybe Brian knows if there is a resistor change, to increase the distortion at middle settings on DIST pot

Pots don't work like that.  Pots simply are a variable resistor.  You seem to imply a "resistor within a resistor" which really isn't feasible.

Funny, the one thing that would get you closest to what you want is the thing you don't want to do.     Either try a different value pot, or maybe a same value with an Audio taper.  It wouldn't require a cap change. 

I'm not trying to be snarky, just being honest.

Good luck! 

[fullenglish]

Tried a 470k linear pot but still the same result, but with a bit more distortion.

Surely a log pot would be even worse as they ramp up at the end of the travel. I would need a reverse log pot if there is such thing.

[diggum12]

Sure there's reverse taper pots.  Very common.  Check over at Smallbearelec.com. 

[Paul Marossy]

Sure there's reverse taper pots.  Very common.  Check over at Smallbearelec.com. 

I'm also inclined to suggest a reverse log taper pot. That might make it more suitable for your taste.

[fullenglish]

Thanks for suggestions.

I have sorted it by putting a resistor across input and wiper lugs of DIST pot.  Its a 50k variable resistor, so not sure what the actual resistance is as i would have to unsolder it and check it. At a guess i would say 15k.

The DIST pot works great now with a more ''linear'' distortion increase. even though taking a reading of the pot, it couldn't be further away from linear.

[Paul Marossy]

Well, at least it works the way you want it now. Thanks for letting us know how you achieved what you wanted.