Re: Bad Clicking on EDP

[Kim Flint <kflint@annihilist.com>]

bobdawg sez:
>>my edp makes that loud ugly click/thump at the end/beginning of my loop.
>>my feed back is set to about 3:30.
>>this makes me sad as the noise makes this nifty expensive device
>>unusable.

>>what can we do to fix this? we are tired of being sad & want to be happy
>>some more. happiness is better.
>>
>>bobdog


At 5:44 AM -0800 11/17/99, Dennis W. Leas wrote:
>Could this problem be that the DC offset needs adjustment?  I thought Kim
>explained how to adjust this but I can't find it in the archives.  Kim?


that would be my guess. Indeed I found my previous post about it in the
archives:

http://www.annihilist.com/loop/LDarchive/199811/msg00303.html

but to make it easy, I'll just repost the instructions for setting the
dc-offset pot again:

*********************************************

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
test.

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.

**********************************************

I hope this will make bobdog happy again.

I guess these instructions should go in the echoplex faq, which seems like
a good thing to do while I'm home recovering from surgery this week. (I
discovered that while heavily drugged on pain-killers, updating websites is
still easy to do. This further confirms my opinion that "webmaster" is the
mcdonalds cashier/gas station attendant job of the future....:-)

kim


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