quick question...

[dave h.]

regarding the softness control of the diode-clipping found in the "simple mods/tips" section of this site, seen here:

can you use this same technique but use two pots, one for each diode? that seems like it should work, and i hope it does because i sort of have an application for it. but before i build anything crazy id just like to hear from you guys if it is actually possible. thanks!

[loscha]

a pot on each diode would give control over positive and negative half clipping individually.
I keep meaning to make a circuit like this, but with a tone control on each side, too, just to see what would happen, if it would do much at all.

but, having the two sides, you could use it to get some fine control over the tone of each side of the clipping.

Hell, you could even make something like a breakout/ab box that had an input, an output, and 2 pairs of thrus, so you can effect the positive and negative side individually.

That would be worth experimenting with, actually.

I'm gonna go try that out in my modular synthesis software.

[Paul Perry (Frostwave)]

That should work fine.
If you are intending to send a symmetric signal to this stage, you might as well use two different diodes, to get even more variation.
(or, a single diode, and replace the other with a pair in series).

[dave h.]

That should work fine.
If you are intending to send a symmetric signal to this stage, you might as well use two different diodes, to get even more variation.
(or, a single diode, and replace the other with a pair in series).

haha weird...

im sort of planning a combination of what you both said...
its an MXR DIST+ circuit, more or less, then in the diode clipping stage, i want to have a negative clip-pot and a positive clip-pot, after which each is run to half of a 12-pin dip-switch, with 4 (2 pos, 2 neg) each of 1n34a, 1n4148, and different colored LED's. so you could get a legitimate assload of combinations, especially utilizing the different clipping voltages provided by the clip-pots. hopefully it will turn out well. i think making a DIP switch accessible from outside the enclosure will prove rather irritating, as i've never made a rectangular hole in something that wasn't plywood before.  but i think it will be a fun pedal with lots of different tones, using all the different combinations of diodes, no diodes, all the diodes, tweaking the clip-pots, etc. but hey, thank you both for sort of verifying that for me! ill be sure to let you know if it turns out alright.

[Khas Evets]

Dave,

I've been toying with a similar scheme. The dip gives a lot of control, but I wonder if I would actually use all the options. I'm leaning toward choosing ge, si or led pairs with the option of adding a ge or si diode to one side for assymetry. What do you think?

[dave h.]

Dave,

I've been toying with a similar scheme. The dip gives a lot of control, but I wonder if I would actually use all the options. I'm leaning toward choosing ge, si or led pairs with the option of adding a ge or si diode to one side for assymetry. What do you think?

i toyed with this idea for a while, and the DIP never occurred to me until i started pricing parts... i was going to have a sp3t selector for ge/si/led on each side and then a "double" switch, and that all got confusing so i thought it would allow more options to have a simple spst switch for each one. neither of those options would fit for under 20 bucks, and the DIP, while it will be hard to "surface mount," allows 12 spst's for under 3 bucks.

so yeah, your idea was basically what i started with, more or less. wanting to switch between diodes and then make them assymetrically clip. the real deciding factor in my layout was just that a DIP switch is cheap, simple to wire, and a hell of a lot less space wasted. what circuit are you basing it on?

i almost wanted to go all the way and have a switch for a couple different opamps/jfets/transistor layouts, so you could get literally thousands of tones. but this is my first "real" pedal project that isn't just a bypass box or channel switcher. its also a lot more expensive because i decided id rather make a PCB, but i need etchant, transfer, etc.

if you go through with it, let me know how it works out, and what switching you ended up using. i ended up with 7 knobs, a DIP and possibly one more toggle, so since im a newb, i thought id do exactly what experts like z.vex DONT do, and lay it out in a humongous 6x4x2.5' sloped console box. on paper, it looks cool! and also let me know if you come up with a good name...

[Khas Evets]

I'm going to do it to a tube screamer circuit. I like the flexibility of the dip switch, and cost. Six diodes each side provides a lot of combiniations not available with switches. I just don't know how to mount it without it becoming a whole other project.

[Peter Snowberg]

I've used both dip switches and jumper blocks for "fine tuning". Both work great, but switches are sure more user friendly. Back about 1988 I wired up dip switches in the spring compartment of my Strat that selected different tone caps. I finally concluded that I preferred a tone stack in the amp instead.

Remember that when you're switching diodes you have the option of always leaving the one with the higest Vf in parallel with the switch and the rest of the diodes. Switching in another one will cause the new one to take over because of the lower Vf. That gives you 7 diodes per side with a 12 positoin switch. (If you choose not to decide you still have made a choice; ahem.... sorry.... 80's flashback)  

There's also the option of subtactive switching like having a string of four Ge diodes in series with a switch to engage the string and then three more switches to short out individual diodes.

[dave h.]

yeah, there is a million and one ways to wire a project like this. i spent hours trying to get it to work simply using weird/expensive 2p3t toggles and crazy business like that.  the on/off switches just seem so much easier, minus the whole mounting bit.
as far as having a diode in parallel with the switch, i rather like the idea of being able to turn them all off, for a minimal dist. boost type deal.

[rubberlips]

I ended up making a vero board with different combinations of diodes - germaniums, red leds, green leds, in4148 and 1n4001's with dip switches. I just solder it in place of any diodes in a circuit and try a few. Takes the guess work out of which ones I like for any circuit.

Pete