Arpeggiator schems out there?

[dirtysteev]

I am looking to build an arpeggiator effect, in which a single note trails off in ascending tones. I am imagining a very Raymond Scott synth-y sounding thing.  Would this be based on a delay circuit?  Can anyone point me in the right direction? Thanks, Steve

[frequencycentral]

Random Number Generator

[NPrescott]

Maybe a link to what you're thinking of? I searched some Raymond Scott, but I got a 50's quintet and some 'put your baby to sleep recordings', no synth stuff 

Rick's is a good suggestion with Doug Deeper's Random Number Generator. Not so much an arpeggiator, but similar is Arnoud's Two Step Octave arpeggiator (check out his Arcade pedal too - pretty slick). If you want to get really technical you could try:

You can make a pseudo-arpeggiator, but it's a bit more complicated.

There was an article in Electronics and Music Maker, UK mag, long ago on how to make a harmony generator. This involved phase locking to a note, then using up/down dividers to generate tones that were major/minor thirds, fourths, fifths, octaves, etc up and down from the base note.

If you did this and then used an envelope to make the dividers switch between generated notes for different voltages, you'd have an auto-arpeggiator.

Used a CD4046 PLL and a clot of other CMOS to do it.

R.G.

or if you're feeling experimental:

One quadrature triangle wave LFO, two PT2399 delay chips (delay time set by LFO) and some crossfade/mixer circuitry:

For one channel of the mixer, "listen" only to that PT2399 which is currently receiving a "rising ramp" signal.
For the other, only listen to the PT2399 which is currently receiving a "falling ramp" signal.
When one of the ramps gets close to the end of its travel, crossfade each channel so it listens to the other chip.

I think this would give you (at one LFO frequency) one octave up and one octave down.  At other LFO frequencies, you'd get other amounts of shift up/down. 

If the triangle wave is symmetric, the amount of up shift equals the amount of down.  If you change the symmetry, then up and down would be shifted by unequal amounts.

Full disclosure, I have no idea if the second suggestion would work. And come to think of it, all the harmony generators I know don't track so well on guitar...but it's a start! I would probably go with the Random Number Generator as it'll be a quick build and then you can decide if you want to go for a more...ah...exotic approach.

[reverberation66]

if you want a serious fuzzed out octave down weird pedal that does some arpeggiation in the midst of shrieking noise yeah the random number generator is a great idea, if you want a clean arpeggiated sound , which is what I'm assuming based on the raymond scott reference, I'd say you'd better find something else.  I've built the RNG and I really like it but its more of a noise pedal than an arpeggiator pedal. 

[Processaurus]

Modding a delay pedal like the Boss DD-3 or a DIY PT2399 based design to have an effects loop inserted into the feedback/regen path, with a digital pitch shifter in the loop, makes for some good arpeggio sounds in the vein of the boss PS-3 pitch shifter/delay.

[dirtysteev]

Thanks for the suggestions everyone. Yeah, I am looking for a clean sound, but thanks for the noise pedal links. Ben, I think you are on the right path, that is also what I am imagining, I just need to figure it out, I'm pretty green still.