help with this mod i found to get envelope controlled delay...

[oald]

i attached the center lug of the "intensity" pot from a lovetone meatball to the center lug of the delay time pot and it gives you envelope delay! i did this with dod dfx94 and although there are a ton of usable settings, half of them tend to make the pedal freak out and power off...
but then i did it to a pds8000 all the envelope settings work with the delay, much better no powering off,


i want to pursue this further, i feel like i just got lucky with the delay trick, i could not seem to get it to work with any other type of pedal...  i was wondering, since I used the center lug on the intensity pot, is this technically right spot to get the 'CV' out of the meatball? the schematic is available here: http://musicpcb.com/pcbs/meat-sphere/

and is there a way to get usable separate outputs for both the up and down positions of the envelope?

and pretty soon I will attempt to attach this CV out(if thats even the proper term) to control the motor speed of a TASCAM multi track, since it has a that tape speed knob i figure it might work in a similar way... but is there a chance i will ruin the meatball?

[expanoncolin]

It would probably be better to wire a separate wire from the U2B's output to a separate new intensity pot and use that output for the envelope out (which you could roughly call a CV out).  If you poke this signal around randomly, it's certainly possible that you will damage the pedal to be envelope-controlled or the meatball.  A much better option would be to use this envelope signal to modulate a vactrol or H11F3 which is being used in place of the pot which is controlling the parameter you want to modulate.  You can't assume that all pots work as CV inputs; most don't.  I don't see the up/down switch on the schem, but I'm guessing it's the one connected to all of the LEDs; this is changing the polarity of the LEDs so it's not possible to get a separate output.  If you want an envelope signal which is modulated in opposition, wire the envelope output to an inverting op amp buffer.

-Colin

[oald]

It would probably be better to wire a separate wire from the U2B's output to a separate new intensity pot and use that output for the envelope out (which you could roughly call a CV out).  If you poke this signal around randomly, it's certainly possible that you will damage the pedal to be envelope-controlled or the meatball. 

thanks! just opened the datasheet, that makes the most sense to use 7 from U2B. i was confused about whats happening on the circuit especially because it doesn't label that up/down switch

A much better option would be to use this envelope signal to modulate a vactrol or H11F3 which is being used in place of the pot which is controlling the parameter you want to modulate. 

so would that be like a duplication of what would happen in the pedal after the U2B output? (substituting for equivalent parts, as I understand people don't usually use LED optocouplers that meatball uses)

[expanoncolin]

Yes, pretty much.  Generally it is much safer to modulate a parameter by replacing the pot with an appropriate optoisolator than it is to treat it as a CV in.

-Colin

[oald]

ok so I rigged things up so that output 7 from the LM1458 is what im using as the envelope out....   much better! stronger signal, but it seems I may have lost the ability to change the envelope direction for this signal.

 oh well, I think I will start working on adding optocouplers for a more usable envelope outputs.



also colin on the june 22nd blog post, about the digital delay rack:  "...or you can set the delay speed (playback pitch) to follow the pitch at the audio input."
am I reading that right? the delay speed is linked to the instrument pitch?
higher notes make faster delay times?
 I think that would be a really nice application to a holding delay like PDS8000, 
really quickly make a sample live and then proceed to use it like a mellowtron

[expanoncolin]

That actually was Crochambeau's post - you'd have to ask him.  On the envelope direction, just wire the envelope signal to an inverting buffer to get the opposite direction.

-Colin

[mikebike]

also colin on the june 22nd blog post, about the digital delay rack:  "...or you can set the delay speed (playback pitch) to follow the pitch at the audio input."
am I reading that right? the delay speed is linked to the instrument pitch?
higher notes make faster delay times?
 I think that would be a really nice application to a holding delay like PDS8000, 
really quickly make a sample live and then proceed to use it like a mellowtron

that would be fucking ridiculously cool

[crochambeau]

D'oh! I just now saw this...

Yes, it does have a function that will clock delay repeat based on pitch at input. I'll see if I can manage an audio demo of that function, it is cool.

It's also very old tech, by a company that no longer exists and I was unable to locate much of anything about them due to the VERY generic terms that comprise the company name (damn you Audio Digital!).

Seems like there would be a few ways to go about recreating the effect these days, depending on what your delay unit uses to reference the front panel control for repeat speed. I'm not well versed in using Arduino, but that's the sort of thing that seems tailor fit...

[expanoncolin]

It's very hard to do any kind of pitch tracking on an Arduino, because an Arduino can't handle much in real time - at most maybe a zero-crossing algorithm.  My guess is that the delay is doing some kind of fundamental frequency estimation circuit, and a frequency multiplication in order to drive the delay clock.

-Colin

[crochambeau]

I wonder if something like the voice frequency to CV circuit on page 10 of this would work as an appropriate interface to Arduino: http://www.loscha.com/scans/Polyphony-1978-10.pdf

Or even to bang out a VCO to drive the delay clock..

[expanoncolin]

I wonder if something like the voice frequency to CV circuit on page 10 of this would work as an appropriate interface to Arduino: http://www.loscha.com/scans/Polyphony-1978-10.pdf

Or even to bang out a VCO to drive the delay clock..

Yes, that's the kind of circuit I meant by "fundamental frequency estimation circuit". I think once the frequency->CV conversion was done, the Arduino would just be acting as a VCO.

-Colin