Ken Stone Psycho LFO

[SonusFluxa]

I've noticed some interest in LFOs on the board recently. This one piqued my interest. Anyone want to give it a go?

[Alex]

PCB and schematic are slightly different.
I've followed the board.

[SonusFluxa]

Thanks a ton! I know what I'll be doing when I get home from work.

[notnews]

Hey Sonus, do you play guitar? I would love to hear how this sounds with a guitar if you could post a demo!

[SonusFluxa]

I do. I'm planning on using it as the LFO for a modulated delay. Once I get it up and running I'll post a demo. I can probably demo a tremolo-like effect as well. I built a crude version of the pseudo-random LFO from geofx last night, if you'd like a demo of that in the mean time, as it seems somewhat similar.

[SonusFluxa]

Here's the my take on the geofx LFO, for now:

http://soundcloud.com/renmyth/modulated-delay-w-pseudo

Now to get started on the psycho.

[edo1123]

What an interesting project.. Where can I find a vero for the geofx pseudo random lfo? And how can I supply this circuit with a 9v power supply? I listened to your demo and it left me speechless ..

[SonusFluxa]

Edo, glad you enjoyed it! I dont think there's a vero layout already done for it. While I was waiting to see if someone would create a vero for the psycho, I breadboarded a version of the geofx pseudo-random, and figured it would be worth a shot to make my own (and also first!) vero layout for it. I did up a quick hand drawn layout, and to my surprise it worked!

I have to download DIY LC, but after I do, I'll post my layout here, so others can give it a shot and probably clean it up a bit.

ALSO, the psycho is verified! I built it last night, but didn't have a positive/negative 15V supply (which I'm guessing is mainly for ease of integration into a modular synth), so I used this:

http://1.bp.blogspot.com/-9dFp71zZ1No/URvNOY56ClI/AAAAAAAABw4/BrOQOfsfOsQ/s1600/NE555-Voltage-Inverter.png

to power it off of 9v. I didn't have a few of the resistor values, but I used ones that were very close. It sounds great, and actually sounds very close to my demo of the pseudo-random. The glide pot is a nice touch, and I'm probably going to jumper the switch, since it makes more sense to me to have that function controlled by just a pot. I can post a demo later on if anyone would like, but I feel like it would be redundant.

As always, thank you, Alex!

[edo1123]

So I can run it with a 9v power supply and that daughter board.. This is fantastic.. I'll build it as soon as possible, maybe I'll try with a tremolo

[zombie_rock123]

Alex: Thanks so much for the layout, cannot wait to try this.

Sonus, how did you find it reacted to the -9v? I wondered if it was drawn up with the 15v/-15v cause that seems to be standard for synth related stuff and it maybe didn't need all that juice.

[SonusFluxa]

As far as I can tell, 9/-9 is fine. I have a similar feeling re the 15v, but I haven't tried it with that voltage yet, so I don't know if there's any difference. At 9/-9, it does exactly what I would  expect/want it to!

[zombie_rock123]

Aaaand I don't have the chip. Grim! Thanks for the reassurance, super excited about this. Weird when the utility boards get your mind going more than the effects themselves! Now to find something to smash it into..

[SonusFluxa]

Which chip don't you have? If you do have the 40106, you might want to try this layout I did: http://guitar-fx-layouts.42897.x6.nabble.com/Pseudo-Random-LFO-td26994.html. I find it to be functionality very similar and with a smaller parts count and footprint.

[notnews]

Sonus - that soundcloud demo of the modulated delay + the GFX pseudo-random LFO sounds fantastic! Do you mind sharing which delay circuit and the signal path you used to create those sounds?

It's hard for me to tell, but it sounds like you're using the s-r LFO to modulate the delay time? Did you feed the LED/LDR with the LFO?

Great sounds man..

[tabbycat]

the max input voltage for the LM358 is comfortably over @ 18v (32v), but for the 40106 max input v appears to be 1ua @ 18v. so doubling 9v with a basic voltage doubling daughter board may well kill it, and long term running at 15v may mean chips don't last long.

fredrik (freppo here) is the boss man on the cmos dark arts. worth checking out his blog page on cmos basics. a great resource he's made available to the diy community if you are getting into that scene.

http://www.parasitstudio.se/building-blog/cmos-workshop-part-1

am planning (much delayed) to go mod synth diy re building, as soon as i finish and box my current backlog of stomps. so am looking for a good lfo. ken stone is one of the touchstone diy people for synths so this looks good for my needs. but i wonder about the '15v = better?' thing too.

and for convenience it would be easier to keep one 15v supply rail feeding everything rather than have a rats' nest of daughter boards and different bits running on differnt power. that's an invitation to blow bits up through carelessness.

i wonder if there are any directly sub-able ics (or close) better suited to running at 15-18v, so alex's layout could be minimally tweaked to suit.

[SonusFluxa]

notnews wrote

Do you mind sharing which delay circuit and the signal path you used to create those sounds?

Glad you enjoy the demo! As far as I can remember, it's the cave dweller with the 2/3 pins of the delay time attached to the output of the prandom lfo. I haven't yet tried the LED/ldr thing, still have to get around to doing that!

tabbycat wrote

the max input voltage for the LM358 is comfortably over @ 18v (32v), but for the 40106 max input v appears to be 1ua @ 18v. so doubling 9v with a basic voltage doubling daughter board may well kill it, and long term running at 15v may mean chips don't last long.

Does positive/negative supply equate to the sum of each? So 9/-9v would effectively give the chip 18v? I honestly don't know, but am curious to find out.

I remember a while back when I first joined the board, you were mentioning your synth interests. Anything new and interesting to report? I've been tinkering on and off with the usual suspects (CMOS droners, various filters), and definitely want to dive in further. Maybe we should start a seperate synth discussion thread?

[tabbycat]

hey sonus, i think it's what you are putting into the live pin on the ic that counts. 18v @ 1ua into it will kill it, as far as i undertstand the data sheets. i'm an amateur so factor that in.

this datasheet for the texas says max 15v though i think the fairchild one or another i was looking at last night gave 18v.
http://pdf1.alldatasheet.com/datasheet-pdf/view/8165/NSC/CD40106.html
either way running it at max or close to probably not good. unlike germanium diodes which break up nicely when pushed ics just tend to break period.
things like 358 and 4558 can go past 20v without problems so maybe the layout could be reconfigured using them, or one of the 14 pin combos, to do the same thing but at higher voltages without running into the red.
i'm planning on making a modular synth out of various bits tacked together, so want to try to stick to 15-18v max for everything, to simplify the power supply side of things. get a dedicated clean 15-18v supply with a lot of kick for headroom and run the lot off it.
the yusynth and ken stone stuff all good. just not too much on verified layouts as yet. electromusic and muffwiggler good sites i keep meaning to join.
i need to get my head together re schem to vero. still painfully slow, though that is partly medical. am awaiting assessment for neurosurgery so concentration seriously lacking. overambitious too maybe.

re new synth stuff to report, nothing since christmas. my baby 8 (minus layout from electromusic) didn't work. i think that layout isn't quite right but their policy re clearly marking verifed and unverified not as robust as here. i built neil's 8 step baby 8 sequencer layout from here but haven't tested it yet (offboard wiring probably a nightmare), along with a handful of 'little bits' that suit synthy experimentation; kinski's filter and a couple of lfos and basic modulation boards that can be patched together to make a tiny basic synth. but health crashed badly at christmas so had to stop everything for about four months.

so plan is to clear my backlog of unfinished unboxed guitar pedals (maybe 20 to box and test) then switch to synth-related-only for a year, until i've got a nice pile of useful electro 'things'.

re a synth thread, a 'build a complete modular synth on vero' would be a nice thread. one of everything, vco, filter, lfo, mod, sequencer all running at 15v and working together would be a monsterous thing to attempt. i suspect it would draw a lot of interest too, as i haven't seen anything like that on any forum anywhere. a bit here and there, some pcb, some just schemos. but not a whole project on vero, all in one place. but am pretty sure the demand for something like that is there.

so what are your plans, ambitions, etc? and have you built anything interesting lately?

[SonusFluxa]

I think I speak for everyone here when I wish you the best of health now and in the future, tabby! I was happy to see you active here again.

I remember having some issues with the -minus- layout for the baby 8, and I think I ended up cross referencing it with proto-schlock's layout. It worked in the end but I ordered those tiny plastic pots with no washers from tayda, so it's been sitting unboxed on my shelf for quite a while. I'm sure Neil's layout is top notch, and I'm still looking forward to building his vanishing point layout.

Other than a few filters, I've been toying with the 40106 in various ways with varying degrees of success, and trying to get my hands dirty with other CMOS chips. I ended up buying the CMOS cookbook, which has proven helpful when I get a chance to crack it open.

I've been enjoying the series of synth tutorial videos Casper Electronics (three cheers) has been making over the last few months. Makes it super user friendly.

I've also been skimming the logic noise series on hackaday. No vero on this or the Casper stuff, but again it explains the concepts in a helpful way. I've slowly been working on getting my schematic->vero game on point for stuff like this.

Another that I found super interesting was this thread on DIYSB. They're taking synth concepts and applying it to stompboxes, but I feel like the general ideas are applicable to creating simple synth modules.

Finally, I did find Repeater, whose PLL circuit I posted on here a bit ago. He hosts some of his schematics on his site, and was a super cool dude when I contacted him about the possibility of posting my layout of his creation on here.

That synth thread sounds like an admirable project that I'd be totally on board to help with in whatever capacity I can.

Ideally I'd like to focus my building time equally on synth and guitar, since I've had a foot in both for as long as I can remember. In reality, I've been getting a lot of requests to build for friends, which I totally love to do. Most of that stuff is guitar related, though.