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This requires that you actually open up the unit, and have it opened with
the power on. *Please follow appropriate electrical safety rules!!* If you
are not careful and you fry yourself, please don't blame me!
There's a trimpot on the PCB, near the left side, by the volume knobs. It's
job is to trim a dc offset from a VCA. Sounds like your's is not set right
for some reason, which would cause the thump you hear.
To set it you need to run one of the built in diagnostic tests. The test
basically turns the VCA on and off at about 60Hz, so if there is an offset
you can hear the resulting tone in an amplifier. (or see it on a scope,
whichever way you like.) While that's going, you adjust the trimmer until
the tone/waveform reaches it's mimimum.
To get into the trimmer test, Start the unit while holding the Parameter
and Record buttons down. Keep them held while the startup screen goes by,
until the display shows all t's. Then let go. Should say 7F. Press
parameter so the "Keys" LED is lit, then press Insert to start the trimmer
You should hear a ~60Hz tone in an amp. (turning input volume off, mix to
"loop", and the output volume up helps.) The tone will change in level as
you adjust the trimpot. Adjust to where the tone is at it's lowest level.
(you'll still hear hashy noise sounds, but the 60Hz should become nearly
inaudible.) After you set the trimmer, pressing parameter again will stop
the test. Then you can turn the echoplex off and power back up normally.
On 12/4/05, zurrigo <email@example.com> wrote:
> Hello all and "nice to be back on the list" after an eventful three
> month including a y2k5-loop-festival-performance with my EDP on
> strike and an upcoming CD release...
> ... I am having a hard time with my looper back in switzerland for
> every time i push the record button or sometimes also the next loop
> one, it gives me that "thump!" noise
> now i can remember having heard someone talk about this issue earlier
> this year but i neither can remember who it was nor can i find it in
> the archives
> so any hints are received most gratefully
> (CD orders are received gratefully, too - but i am afraid that pay
> pal button on my website doesn't seem to be working yet and i imagine
> no one here wants to give me any hints about how to deal with that
> worst pal i've ever dealed with...
> ...anyway, check it out: http://www.mem.li/e/craft-paypal_e.html)