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Re: sync-ing non-midi loopers/ cheap stereo loopers???



At 7:41 PM -0800 12/10/99, David Myers wrote:
>>At 9:24 PM -0800 12/9/99, Jax1723@aol.com wrote:
>>>I was wondering:
>>>Say you had two non-midi loopers (headrush A and headrush B).   Would 
>it be
>>>possible to open them up, disconnect the footswitches in A; then hook 
>up the
>>>footswitches in B to both units (i.e., one set of footswitches for two
>>>units)?  The $64000 question is: Since both loops are starting/ending 
>at the
>>>same time, would they stay in sync or IS THERE SOMETHING INTERNAL THAT 
>WOULD
>>>CAUSE THE LOOPS TO FLUCTUATE?
>>
>>no, they won't stay in sync. You have some crystal oscillator clocking 
>the
>>system logic of your headrushes. It is pretty much impossible for two 
>clock
>>oscillators to have exactly the same frequency. They will be within some
>>tolerance, so they will be close, but not exact. Clock oscillator
>>frequencies will also drift a bit with temperature, age, and the 
>tolerance
>>of the load caps on the crystal. If you have no feedback mechanism to 
>keep
>>the clocks synchronized with each other, they will drift from each other.
>
>Absolutely true, but might there be some way for the two units to share 
>one
>crystal/clock?

Not easily. Most convertors have their own crystal oscillator, so you would
have to add a buffer chip to tap off the crystal input on one and drive it
to the other. This clock will be either 16.934Mhz or 24.576MHz, high enough
that sending it over a wire to some other unit will cause it to have a lot
of reflection and ringing problems, certainly causing it to fail miserably.
If you know what you are doing, you could choose a proper buffer IC,
terminate properly, use the right kind of cable, and make this work, but
then you are way outside the realm of amateur electronics
hacking.....Consultants who know how to do this charge about $150/hr and
up.....


>>This means, you'll record two loops that will start off together. As they
>>loop, the slight differences will cause the loops to slowly drift apart,
>>causing phase problems, then flamming, then just odd rhythms. Sometimes
>>this can be obvious very quickly, sometimes slow. Just depends on the
>>natural random variance between the clocks on the two headrushes.
>
>Cool!  This is just the way I'd want it, myself....

I'm guessing if he wanted to do that, he wouldn't have asked the question. 
:-)


>>If this is what you wanted to do, you got the wrong product. Headrush
>>doesn't have any sync features, it's just a simple pedal not intended for
>>such use.
>>
>>kim
>
>No doubt, the wrong product.  Personally though, I think I'm actually
>happier with a Headrush and a couple of Zoom 2100's getting weird against
>each other than I was with the elaborate EDP.  But maybe that's just my
>problem....

to each his own of course.....I find I can do far more useful as well as
far more crazy stuff with a couple of echoplexes than you could ever hope
to do with headrushes and zooms, and the echoplex is simpler to use too,
but then I'm totally biased. :-)

kim

______________________________________________________________________
Kim Flint                   | Looper's Delight
kflint@annihilist.com       | http://www.annihilist.com/loop/loop.html
http://www.annihilist.com/  |