Hysteresis Oscillator new effect (555, stutter, atari)

[Paul Perry (Frostwave)]

Alright all you circuit heads. Is there any way to null that click on the pulse of the oscillation?

The first thing I would try, is a 7555 (or other CMOS version 555).

[choklitlove]

i never even knew they existed.

consequently, i know nothing about ics...


a c1555 would also work, right?

[choklitlove]

okay, i see.  it's the same situation as the thing modulator, correct?  in the case of the T.M., while an LM567 works, to supress the oscillation while not playing a little, you need a LMC567 or a cmos version of the 567.

so, the cmos chips are basically upgraded, higher quality chips with "much lower power dissipation and supply current spikes" (from the national site.)

an lmc555, c1555, and a 7555 would all work, right?  just checking before i go to order...  thanks!

[Noplasticrobots]

A great and  interesting sounding circuit! I haven't done anything DIY related for some time now and I'm breaking out the breadboard as we speak to give this circuit a shot.

[Noplasticrobots]

What about a TLC555 available from Rat Shack? I used one in my Ugly Face with no problems.

[Paul Perry (Frostwave)]

I expect there will still be teh unwanted oscillation when the signal is low, but perhaps the objectional clicks will be lessened by a CMOS 555 that draws less current on switching.
And the TLC555 - or the others mentioned - should be fine, I expect. Good luck!

[slacker]

looks cool, I'll have to find some breadboard space for it. You might be able to get rid of the clicks with more powersupply filtering try increasing the 22uF and putting a 0.1uF in parallel with it. A small cap between pin 7 and ground might take the edge off the pulses.
I can't really tell if there's much bleedthrough when not playing but adding input and output buffers to the audio  signal might help. That works quite well for the thingmod.

[orgaqualia]

I found this here:
http://home.cogeco.ca/~rpaisley4/LM555.html
Among other things, it says:
" It is also good practice to place a 0.1uF - bypass capacitor (C1) across the power supply and as near to the timer as possible. This will reduce voltage spikes when the output transistors of the timer change states."

I don't know if this is the problem but it might work

Possibly put it before the 5.6k resistor in the schematic?

[choklitlove]

i didn't think this was worth a new thread.  just to let you know, i updated this layout.  nothing changed with the circuit, but i tried some new layout techniques like thicker traces, new fonts, using PNG instead of GIF, and a couple other things.  i'm posting this to see what you guys think.  thanks!
http://www.geocities.com/worthekik//hysteresis.html

[John Lyons]

Choklit
Did you try the alternate RS 555 chip and the other suggestions? Any differences?

John

[Paul Marossy]

Huh, the first part of that soundclip sort of sounds like an amp with a tremolo that shifts the bias using a phase shift oscillator. Anyhow, interesting noises this thing can make. 

[choklitlove]

Choklit
Did you try the alternate RS 555 chip and the other suggestions? Any differences?

John

i bought a csmos 555, but haven't tried it yet.  i took this off of the breadboard for something else, so maybe i need more breadboards.  anyway, i'll post as soon as i try it.  actually, the self-oscillation doesn't bother me that much.  but, i'll let you guys know.

[choklitlove]

i've been messing with this circuit.  i've tried a cmos 555, and i haven't been able to get the slow stuttering that the regular 555 has.  i have tried the regular 555 with several different mods.  i have changed the .33s to .1s.  that doesn't change anything, but they are easier to get.  anyway, i've also tried several variations of .1, .01, .001, 47pF and many more caps from the output to ground.  also pin 7 to ground.  some effectively cut the treble, which softens the oscillation, but not enough so it isn't worth it.  it's just like turning the tone knob down.  i also tried the "100k/100uF network on the power pin" thing from the thing modulator.  i tried several variations of that to no avail.  i've also found that the 22uF wasn't doing anything (that i can tell), so it's gone now.  the oscillation is controlled by the 250k pot and the 5.6K resistor.  i've been experimenting with a 10k pot in the 5.6k's place, which allows for a little slower chop.  so, i might change its value as well.

other than that, i haven't really found anything to "better" this circuit.  the ticks are still there.  what else do you guys suggest?

[Cursor]

Hmmm, I don't get this clicking problem in the Hysteresis Osc and I'm using the good old NE555. I'll have a poke around tonight..

[birt]

this might be completely stupid.

i was thinking about a transistor switch that only turns on with a voltage spike and only lets that spike pass to an inverter to the output. so it's out of phase with the output and is just canceled out.

[caress]

i did something that sounded exactly the same as this with a cd40106.  it was on a bugcrush bitcrusher and i added the lfo section from the WSG on the 40106.  i was originally thinking that it would work like an LFO for the sample rate, but it must have been pushing the audio through instead.  fun.  it had the clicking as well...i could never get rid of it.

[Paul Perry (Frostwave)]

Maybe a slew limiter would tame the spike?
A slew limiter is just a circuit that sets a maximum rate of change of a signal, so instead of a square wave beign square, it can only rise and fall at an angle. There is a very basic approximation http://www.musicsynthesizer.com/Circuitry/varilogic.htm on this page, just use any fet & ignore the +-15, just put +9 and ground on it, it's only a buffer. I havn't tried it, but it would be easy to check.
(yeah I know that's not a REAL slew limiter, but I think it is going to smooth the edge).

[oldrocker]

Cool!   I've been looking for something that I could use all of these 555 IC's I have laying around.  It sounds very similar to the Analog Bit Cruasher I just built but much easier.  The Bit Crusher doesn't have the stutter effect either.  I'll have to give this a shot soon.  As for the ticking (what else is new) I'm always dealing with that.

[Cursor]

Had a look at my click-free build again. In case it helps anyone, it's absolutely stock with choklitlove's parts values, albeit with an NE555N. The input comes off the end of a 5088 distortion and the HO is followed by a modified BMP tonestack. I've got a 47uF cap across the battery.

[cjb]

Looks simple and fun...I have a couple 555s laying around.  I was going to build a Tremulus Lune next, but I might get sidetracked and breadboard this one first...