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Subject: Re: [motm] Gate and Trigger Delays

From: media.nai@...
Date: 2003-05-16

>There's no "right answer" to how gate and trigger delays should work;
>everybody has their own opinion.

I agree :)

> >This is important because it seems to me if multiple events are to
> >be all delayed and fed through to the delayed output, the circuit
> >must be a sort of 1-bit shift register with the delay control either
> >selecting a tap or controlling the clock speed. If multiple events
> >are not to be preserved a simple analog circuit involving a
> >capacitor for timing and a couple of analog switches will do the job.

I have a circuit here that uses a flip-flop, two 555 timers, and a
couple of NOR gates. It will preserve pulse width, if and only if
the pulse widths are less than the delay time and the period between
pulses is more than the delay time.

I do not think it is possible to exceed those limitations without
building anything less complicated than a "real" digital delay.
That's out of my league. I can only cobble discrete CMOS together.
I don't monkey around with microprocessors.

I also do not think it is possible to do it with only one timer, and
you would need a current source since it's impossible to match (and
in most cases buy) a dual pot. Imho, a modular approach with
separate timers, logic gates, edge detectors, etc. is much more
flexible.

Yes, you could use the tempo clock to drive shift registers to delay
gates, but only by a number of clock steps. Which I don't think is
all that useful.

This leads to an important question, what the uses for a gate
delay?? If it is to delay things less than one beat, such as setting
back a snare or delaying the onset of an envelope or LFO, then the
analogue solution will work.

>Multiple events need to be preserved.
>
>Here's a sneak preview of my logic delay line that also works as a
>gate/trigger delay:
>
>http://www.tellun.com/motm/diy/tln774/TLN-774.html
>
>This panel mockup is already a little out of date, but the thing does
>preserve both edges of a signal and stores multiple events. In my
>opinion, that's the only way to go.

Imho, if you are going to do that, you might as well make a digital
delay that can process control voltages as well as gates. Let's say
an 8-bit delay instead of a 1-bit delay. The sampling rate wouldn't
have to be that high for CV. This way you could delay all the
information required to play a note (not just the gate) and could use
delay effects to modulate that CV. A DC-coupled digital delay would
be very useful. I think I saw a mock-up for an MOTM module like that
a long time ago.

>BTW, great Jerusalem rendition.

Definitely :) Imho, I thought the drumming was no Palmer, but I
thought the singing was better than Lake. Did you know Blake wrote
the lyrics??