Any circuit designers want to have a go at something for me?

[robbiemcm]

I want to build a tremolo that has no attempt whatsoever to be smoothed out or anything like that. I'm trying to get it to be literally an instant change from one volume level to another. I don't know of any circuits that can do that, if they can just quickly point me there and we'll be done, but maybe someone would like to have a go at it. I'm sure you could model it slightly on a flashing LED circuit. It would be cool to have Volume/Speed for both "sides" of the tremolo, that way you could have a short lower volume aprt and a longer normal one, or do whatever. The only thing I'm worried about is that as a volume pot would effectively have a route to ground and the resistance will vary, this could change the speed of the "sides"as the speed would be controlled by a pot aswell I imagine. I'm not sure, which is why I thought I'd come here.

Thanks for any assistance you can lend,
Robbie

[bioroids]

You mean like, having a totally square waveform, with no smoothing of the borders? that would probably cause noises when the sound is chopped (besides the noise caused by the modulation itself, wich is harder to remove on square waves).

I think you can smooth the waves a bit, to eliminate the noise, but still hear it as choppy and square, for example using a "trapezoid" wave.

Luck

Miguel

[gez]

If you mean a 'stepped' sound, something like Miguel designed hooked up to an OTA:

http://www.diystompboxes.com/smfforum/index.php?topic=37626.msg264558#msg264558


Thing is, to eliminate clicks you need to do a bit of filtering, and the degree of filtering you need to eliminate the clicking tends to smooth things out (with stepped waveforms) so you might not get the effect you're after.

[Peter Snowberg]

Type "stutter" into the search and you'll get a bunch of responses.

Try this one first:
http://www.diystompboxes.com/smfforum/index.php?topic=26900.0



It sounds like you're asking for a pedal with four pots.... one for speed, one for duty cycle, and two for the two volume levels to select. You could simplify by making one of the volumes 100% with the other cut by the selected amount, but I could also see use for the two volumes independent of the bypass volume. I havn't even looked at R.G.'s circuit, but I'm sure it can be modified as you desire.

[MartyMart]

As mentioned in peters thread link, a "Kay Tremolo" will get you very close
to square wave trem.
No clicks and you could probably tweak it to be more radical !
Nice n simple too

Marty.

[bioroids]

I have to try the Kay tremolo! I don't know why I always overlook it

Miguel

[Transmogrifox]

Here's my latest swing at the PWM based tremolo/ring modulator design.  It's pretty rad sounding:

http://putfile.com/pic.php?pic=10/2942051539.jpg&s=x10

Using a ramp generator LFO, it has some settings that make the guitar signal sound like there's a delay pedal on.  It's an interesting mind trick.

Using a square wave it is possible to get some very sharp on/off patterns and the ramp LFO is pretty crazy as well.  The draw-back is that the ramp and square waves cause a click/tick sound if they're not filtered to soften the sharp edges a bit.  This is still very much a work in progress and I don't recommend building off this schematic since it does not show a pot for DC shift on the carrier input, nor is there a depth control.  Without proper tuning of carrier amplitudes, you will experience more click in the signal path, though with a bit of filtering on the carrier and adjustment of offset to within +/- .5 mV I have accomplished a circuit that is a ring modulator that lets no audible carrier through, even driving it into my amp's high gain channel cranked to max gain. 

As I work on this, I intend to add some circuitry to convert the ramp carrier into a triangle wave, and a nonlinear network to get a sine shape out of the Tri, in addition to a simple low-pass filter for the carrier.  I think I should also use another comparator to pulse-width modulate the carrier ramp, as well and maybe even add yet another LFO for modulating the pulse width of the carrier for some more interesting synth sounds.  The ramp used in the ring mod already helps get some interesting synth sounds.  The bells and gongs effect sounds distorted with a ramp, but are very nice with a triangle, sine, or filtered square-wave LFO.

Let me know if you're interested in something like this.  I'm about to take off for the evening, or I'd throw down some sound clips to post.  Perhaps I will get to the audio samples later.

[robbiemcm]

Transmogrifox: Some audio clips would be really nice, it sounds interesting.

Anyway, I'll try to explain it better this time. You could think of it like this, although I'm sure it's not this simple, I doubt you can simply direct the audio signal down different tracks. But anyway, think of two tracks both with a potentiometer to ground, just in the same way you see most volume pots on circuits. Basically the audio signal could be sent to these tracks for a variable amount of time, both having their unique speed pot so that one could be on for a short amount of time and the other for a longer. The benefit of volume pots aswell is you will definitely have the range from 100% to pretty much 0%, I'm not sure if most tremolo's depth control goes down that far? It could be simplified by having one track that is 100% like Peter Snowberg said, and then maybe a trimpot to make it so the bypass and effect are pretty much the same volume. Anyway, as I said I doubt it's that simple, but maybe that'll give you a bit more of an idea of what I was trying to say, my first post might not have been too clear.

But it sounds like it's quite a bit harder than I thought, and that it will be full of clicks Maybe if that's too hard it would be easier to make an on -> off stutter one, except keep the speed unique for both on and off? Although that will probably still be hard anyway, lol.

[petemoore]

  I need to mark the controls on my Tremulous Lune.
  This thing does a super wide variety of tremolo forms, probably more knobs than what you described desires, but you can certainly have fun for hours trying all the different Tremolos.!!!

[Transmogrifox]

The thing that keeps me entertained is getting the sounds of bells, gongs and other metallic percussion from plucking a guitar string.  It sure is fun.   

That Tremulous Lune seems like a winner.  Maybe I'll build it one of these days--if I can stop experimenting and just go hardcore and build a bunch of useable stuff.

I have posted audio samples of this effect in another thread.  I'll stick one link here of a track that demonstrates the ramp tremolo pretty well:

http://media.putfile.com/TremDelayNoFX

The "NoFX" addition to the end is not referring to a punk band, but I copied the track after saving this one and added a phaser, filter and reverb just to play around and also demonstrate some of the possibilities when it's combined with other FX.

Enjoy

[puretube]

I  think I`ve designed s.th. like that...
it`s not 2 different speeds per se,
but the "silent" ( "off" ) time can be varied from ~1% to ~100%,
while the "loud" ( "on" ) time will be varied accordingly from~100% to 1%
with a "duty-cycle" pot;

The "on" volume is always 100%,
while the " off " volume can be varied from 100% ( = no attenuation: as loud as the "on" signal, i.e.: no modulation/volume-difference),
to 0% ( = full attenuation: zero signal during the "off"- time ),
and even further to minus 100% ("off" signal as loud as "on" signal, but oppositely phased)
with a "depth" pot.

LFO can be switched from squarewave modulation to triangle modulation.
Speed can be varied from ~1/15Hz to 70Hz
with a "rate" pot.

[robbiemcm]

Puretube's one and the Tremulous Lune seem to be very interesting, but I really am looking for variable speed for both the "on" and the "off" section of it, does anyone think that could be possible in anyway without having to go digital?

[gez]

As Ton points out, varying duty cycle will give you different on/off ratios.  If you want a square wave response, i.e. on/off or a least 'choppy', then clicking can be eliminated, all depends on how you do the modulation.

With an OTA doing the honors I've managed to eliminate tick by converting the square into a trapezoid.  If you were using LDRs they would be pretty silent, though they're going to result in an asymmetric duty cycle in the first place due to their sluggish nature.

[robbiemcm]

The Tremulous Bear seems to have a Speed 1 and a Speed 2, anyone able to tell me whether its worth the build? Maybe a sound clip?