Re: JamMan regen discussion

["Michael P. Hughes, Ph.D." <pycraft@elec.gla.ac.uk>]

Sean:
>>the JM is set in DELAY mode with a feedback level 1 and MIX all the way 
>to
>>the right - ie it produces one repeat only.  The signal goes from the 
>Left
>>output to the other amp input.  The signal goes from the Right output to 
>a
>>volume pedal and back into to Right input.
>[snip]
>>The only drawback is that you have to spend time balancing the "input" 
>and
>>"output" levels - about 2 o'clock and 12 o'clock work for me.  And
>>surprisingly, noise doesn't seem to be a major factor even though the
>>signal is constantly shifting between digital and analogue.
>
>A cleaner solution if you can live with only 16 settings of feedback, I
>would think, would be to use an expression pedal and some kind of MIDI
>filter that converts continuous controller values to the appropriate
>program change messages. 

I'm sure this would offer the same degree of control.  I doubt anyone
around here could discriminate between more than 16 levels of feedback!
The reason I'm happiest with this system is that I seem to have a
deep-rooted fear of anything programmable.  No, really - I have a terror of
turning up to a gig and finding my processor/MIDI filter/footswitch etc has
forgotten its presets.  So I get by with a bunch of pedals and my
non-programmable JM.

>Personally, I much prefer just turning the feedback knob to 13 or
>whatever, because then I get a rate of fade that I know exactly what
>it is.  (I.e., I'll be playing along and think, oh, I want stuff to
>fade out faster, probably at 11 or so.) 

I used to use the knob, but I was dissatisfied at the way in which it
tracks. I'd grab it and QUICKLY turn it all the way around, hoping to go
from 1 to 16 and finding it only got as far as 3.  It doesn't like being
turned quickly.  And there's no easy way of getting from 1 to 16 - sadly
the encoder won't roll over for 14-15-16-1-2 etc.  You have to go all the
way back.

> If the continuous control
>had some kind of digital readout (perhaps the plex does), that would
>cover that need, but I don't see how you could reasonably do that
>if you're using an analog volume pedal in the feedback loop.

Whoever mentioned the visual volume, thanks!  It actually should be
relatively easy to build something like that into a standard volume pedal.
Put a double-ganged pot in the pedal, drop a voltage across the second
track and use the tap to drive an array of LEDs.  You could probably source
near-completed ccts from your mail-order electronics company (is that
Mouser over there? It's Maplin here).

Michael

 Dr. Michael P. Hughes, University of Glasgow, Glasgow, UK G12 8QQ 
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