Speed/Rate controls

[HeavyXIII]

Alright, if someone could give me a rundown I'd be eternally grateful.

What determines the range of speeds a knob provides? Are there any kind of resistors or parts that change how fast or slow a pot can get? If so, is it reasonable to believe that several can be wired to a toggle switch and changed for different rate settings?

I've got access to a DIY tremolo pedal, and I'm trying to figure out if I can add a pseudo ring mod function to it without removing it's tremolo function. I don't have it on hand to open up, but it's almost an exact clone of the Tremulus Lune. Is it possible to adjust the rate knob to reach speeds that produce ring modulation sounds?

[eatyourguitar]

What determines the range of speeds a knob provides?

this depends on what circuit you are referring to.

Are there any kind of resistors or parts that change how fast or slow a pot can get?

depends on the circuit. there is always a way to modify something to get more range of speeds unless it is some behringer pedal doing signal processing in software on a chip.

If so, is it reasonable to believe that several can be wired to a toggle switch and changed for different rate settings?

if by several you mean 1 or 2 positions plus the center off then yes, you can do this with a toggle switch. if by several you mean more than 2 additional settings, you would need a rotary switch or something even more elaborate.

I've got access to a DIY tremolo pedal, and I'm trying to figure out if I can add a pseudo ring mod function to it without removing it's tremolo function. I don't have it on hand to open up, but it's almost an exact clone of the Tremulus Lune.

can you be more specific as to what you mean by pseudo ring mod? on bug brand, pseudo ring mod is done with square waves. it sounds like 1 bit audio. some other uses for the term pseudo ring mod can be to describe a ring mod circuit that is less than perfect. and some people are even more pedantic in saying that four quadrant multipliers are only real ring modulation if they are built using a real diode ring. also, why would you set your requirements so low? is there a reason you would want pseudo ring mod over ring mod?

Is it possible to adjust the rate knob to reach speeds that produce ring modulation sounds?

four quadrant multiplication can be done at any frequency just as any two real numbers can be multiplied in math. it even works with zero and double zero. the modulator can go all the way down to dc if the ring mod is designed properly and DC coupled. I think you may possibly have ring mod confused with some very fast amplitude modulation. IIRC the lune has vactrols in it so they will simply slew anything over some frequency and make it impossible to get fast AM

[mysteriousj]

Hey man! Yeah you can.It's pretty easy.

...Just taking a quick look at the Tremulus Lune schem, see the speed pot and then see after that there's a "fine trim/resistor" you'll want to remove that, make it a short but probably best to leave the 100R resistor. See the 100u cap that gets charged up by those resistors change it from 100u to 10u. You'll also probably need to change the 10n filter cap to something like 1n as well.... or else it might filter out the oscillations completely. That all should set the maximum freq at about 200 Hz. In reality I'm not sure how well it will work.. the LED/LDR have a slow response so you'll be pushing them to the limit at those sort of speeds. Find as fast an LDR as possible.

You'll also wanna up the pot size to like 100k if you still want it to be able to go slow.

Hope that helps.

[HeavyXIII]

can you be more specific as to what you mean by pseudo ring mod? on bug brand, pseudo ring mod is done with square waves. it sounds like 1 bit audio. some other uses for the term pseudo ring mod can be to describe a ring mod circuit that is less than perfect. and some people are even more pedantic in saying that four quadrant multipliers are only real ring modulation if they are built using a real diode ring. also, why would you set your requirements so low? is there a reason you would want pseudo ring mod over ring mod?

four quadrant multiplication can be done at any frequency just as any two real numbers can be multiplied in math. it even works with zero and double zero. the modulator can go all the way down to dc if the ring mod is designed properly and DC coupled. I think you may possibly have ring mod confused with some very fast amplitude modulation. IIRC the lune has vactrols in it so they will simply slew anything over some frequency and make it impossible to get fast AM

I don't have the time, money or pedal board real estate to spend on a legitimate ring modulating device. I have a Moog MF-102 on hand, but it's twice the size of everything else I own, not to mention I hate the "always on" drive control it has. True bypass loop is pretty much out of the question ala real estate limits.

The time I spent with the Moog showed me that while ring modulation is a cool sound I won't use it enough to warrant trying to carve out a spot for something that will only be used for tremolo. Modifying this smaller pedal made sense because I could fit it on my board and is completely bypassed when I turn it off.

I appreciate the advice on the simplicity of this modification, but if the vactrol scenario tells me anything, then the modification might not produce the desired result by not making an audible frequency. I think I'll just leave it alone and aim at a different pedal or something.