Sample/Hold progress Report for Chris & Munky

[Transmogrifox]

I built my initial "back of the envelope design" version of the S/H circuit last night.

The concept works amazingly well.  I am stoked about how well my random sampling idea worked, and the filter choice is good too.  I implemented a "Wheel of Fortune" concept to a 4-bit binary counter, and it seems to randomize the filter sequence quite well.

The draw backs now are similar to ring mod problems:  Clock Feed-through.  I have a couple more ideas about minimizing this later this afternoon, but right now it is atrocious, even though the moving filter effect is great. If my more recent ideas don't work, my switch modulating is going to have to get more complicated.

The other problem is I designed it to use a frequency range that went up to 4 kHz, so it spends much time in the barely audible range.  I redesigned my filter center frequencies to give it a max at 2.3 kHz or so, and I'm hoping that there will be more movement around the "wah" range with this mod.

I will try my best to get soundclips of it.  I don't have my own computer, so it has been hard to record.

[Marcos - Munky]

Cool to hear about the sample/hold filter. I'm curious to see the schematic.

[Arno van der Heijden]

Cool! Me like random effects!!! Can't wait to hear some soundclips!

How much is this different from the (Maestro) S&H? Is this simular to the Zvex Ooh Wah?

[Chris R]

cool!  i'd like to check out a schem too.

C

[Transmogrifox]

Cool! Me like random effects!!! Can't wait to hear some soundclips!

How much is this different from the (Maestro) S&H? Is this simular to the Zvex Ooh Wah?

***Do you have a link to the Maestro S&H?  I'll check it out and tell you how similar it is.***
Edit:  I found the schematic.  The answer is no, this is not much like the Maestro S/H.  The Maestro takes the equivalent of an envelope-controlled wah and drops a semi-random varying voltage on the Wah control.  It looks like it also has an envelope control as well.  

Mine uses a 4-bit binary counter IC to get 16 discrete center frequencies and the S/H controller...random number generator, whatever you call it randomly selects from the 16 available frequencies.  All the filter frequencies are calculated to be centered as near musically-related frequencies as standard resistor and capacitor values will allow.  Last night I observed that it actually sounded similar to a synth arpeggiator when I listened to it filtering noise.

I am led to believe that the randomness of the S/H generator is somewhat periodic in its repetition, though too complex to pick out the cycle in the pattern.  All I need to do is make my pulse-width generator more susceptible to random electrical noise and temperature effects.

Those of you who wanted to see a schematic, I can scan in the working copy I have now...but please keep it to yourselves.  I'm happy to distribute ideas for people who like guitar FX and are hobbyists like myself, but I don't know that I care to see this thing beefed up by a commercial entity and thrown on the market..."beefed up" meaning they take the idea and work the bugs out.

However, Sample & Hold is a well-established effect, so I don't suppose that people are crouching in the corner of this forum to snatch up something that sounds like what they already have available on the market.

On that note, if you want a schematic just for the sake of curiosity, or even if you want to join the project and help improve it (that's what forums are for), email me transmogrifox@yahoo.com and I'll send the current design in an attachment.

random FX IS cool.

[Transmogrifox]

Alright.  check your email.  I sent the scanned "up-to-date" version.

I went gigging with it on my breadboard last night.  Everyone who comes on stage looks at the floor and they're like, "How do you keep it all straight?", or "How do you know how to wire all that?" or maybe a simple friendly, "What the hell!???".

I don't think anybody in the audience picked up that it was home brew...which means that the glitches weren't severe enough to attract attention.