TREMMY TREMOLO

[loylo]

Very nice projet, DA!
You convinced me to breadboard this kind of filter for synth like sounds, in conjunction with my tremulus lune, trivibe and echo box.   

Before wanting a third LFO ( ), you could wire a switch to make the second LFO modulate the speed of the first LFO when you don't use the filter. It's a nice feature I added to my tremulus lune, in order to make rythmic choppy sounds, like in this video à 5min:

[deadastronaut]

WHOAAAAAH....

arghhhhhhhhhhhhhhhhhhhhhhhhhhh my head....


nice feature..

[loylo]

 
You can find some informations on the Tremulus Lune site (commonsound as far I can remember).

[deadastronaut]

a vid of some tests while on breadboard/s...... ...getting there slowly...

[bluebunny]

Rob is...  Jean-Michel Guitarre.   



(^^^ And that'll be one of his LED trinkets...)

[deadastronaut]

Ha ha bonjour bleu bleu bleu....

[bluebunny]

Ha ha bonjour bleu bleu bleu....

LOL.  That's funnier than you might imagine.  Just between you and me (I can't imagine there's anyone reading this...) the "bluebunny" moniker is from my late French grandmother's pet name for me when I was a kid - "lapin bleu".  

A toute à l'heure, astronaute mort...  

[deadastronaut]

le lapin bleu ha ha 

drôle les choses que vous êtes appelés comme un gosse,

J'ai toujours été nervuré pour mon nom de famille henry, henry VIII toute l'heure sanglante ..


anyway......

back to old blighty...

[deadastronaut]

anyway...

i still can't get this filter depth sorted, i tried sams suggestion of a pot in series with the filter caps, which works..kind of.

but when depth is fully off i get hi freq hiss...hmmm...


also ive been trying to tame ticking from the filter too when at high speeds, and whooosh at low speeds....(when clean)


the tremolo side of things are great...(still not happy with the depth control though) but other than that really cool.


its just the filter side of things really....

[samhay]

The depth control on the filter is a bit of a kludge. You could try doing it on the LED side of the vactrol.

^but when depth is fully off i get hi freq hiss
Have you tried a small cap across the 470k resistor?

[deadastronaut]

cheers sam i'll try that cap...

i tried that led too, tried all sorts,

i tried the 'kludge' method again , with a 47pf, had to put a 1uf electro before the pot to stop 'DC scrathchyness...

pretty smooth control now...


edit: which is cool as now i won't need a switch for the filter either...excellent.

[samhay]

excellent

^had to put a 1uf electro before the pot to stop 'DC scrathchyness...
That got me thinking - why not put the depth control between the two 2n2 caps, which led to a slightly less kludged depth control in the updated schem here:

http://www.diystompboxes.com/smfforum/index.php?topic=107197.msg975196#msg975196

No idea how well it will work, but the sim gives a much flatter response with the depth at min, which may work better if you don't want to switch it out.

[deadastronaut]

yep that works too....but cuts a lot of the full sweep  off..

so back to kludgey no.1 it is...seems to work nicely anyway...




now for this bloody trem depth, ive tried sticking a 1k across the 1k pot but its still all bunched up, 3/4 of the pot does bugger all

i haven't a 1k log pot to try in reverse.....only lins..hmmmm...

another way of trem depth control?...

[samhay]

ok, it might work better with a larger pot, but I will have a play on the breadboard at some stage.
RE: depth control, it might be worth auditioning a few LDRs to see if one works better than the others.

[deadastronaut]

whoohoo...got it, R17 to a 3.3k instead of 2.2k...perfecto..

nice range from 0 to full on chop...sorted..much better.,

goes nice with the filter sweep/mix too....pukka!!!..

[deadastronaut]

any other filter to whack on this while i'm at it..?....recommendations?..

state variable?

[duck_arse]

rob, it's not a filter, but you did ask.



I haven't tried this, and was going to ask for a volunteer. I see your hand up. R1//R2 (from your first posted circuit) set the symmetry of the osc, going from saw up - triangle - saw down, I'm sure you know this. so, wobble that ref voltage with another lfo// led // ldr, and what will it sound like?

the values might need tinker, use a 4k bright~500k dimm ldr, the 2 circuits will work slightly different. if they work at all, that is.

have fun.

[deadastronaut]

cheers DA , but i'll stick with what i have at the mo i think...mt breadboards are a bit cramped already..


one idea that came to mind whilst floating around the earth was this...

if i can get the filter side of things to be a constant volume, rather than dipping and swelling, it would be more like a phaser...

possible?...

[bluebunny]

whoohoo...got it

Good sign.   

possible?...

Bad sign.      There may be another seven pages before we're done with this!   

[deadastronaut]

Lol...

most likely...