Re: EDP Noise Problem

["muman" <muman@eskimo.com>]

Hello Kim,
Again you have come through for me. You helped me out many years ago when 
I 
was having problems getting me feedback pedal to work correctly.

This removed the problem.

Thank you very much.


> At 03:53 PM 9/1/2005, muman wrote:
> >Hello all,
> >After every loop, my EDP makes a quiet thunk sound. I have Loop IV
> >and have the memory maxed out. I think it's an early generation
> >machine.
> >
> >Anyone have any suggestions?Louis Hesselt-van-Dinter
> 
> Hi Louis,
> 
> There is a trimpot in the Echoplex that may need to be adjusted in
> your unit. It is there for nulling out dc offsets at a VCA, which can
> cause this thumping at the loop startpoint. Normally the trimpot is
> set at the factory and should not need adjusting, but maybe it got
> knocked out of adjustment somehow in your case.
> 
> I posted instructions on how to do this adjustment once long ago, it
> is here in the archives:
> 
> http://www.loopers-delight.com/LDarchive/199811/msg00303.html
> 
> However, I realize those instructions need to be updated a little bit
> for Echoplexes using LoopIV. So I'll just repost it now, updated for
> LoopIV:
> 
> 
> *********************************************
> How to adjust the Echoplex dc trimpot (LoopIV version):
> 
> 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.
> Its 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 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 test is running, you
> adjust the trimmer until the tone/waveform reaches its minimum.
> 
> To get into the trimmer test, power up the unit while holding the
> Parameter and Overdub buttons down. The display will show a version
> number of the test software at first. When you let go of the buttons,
> it should say 7F.
> 
> Press the parameter button so the "Switches" LED is lit (or "Keys" on
> older units), then press Insert to start the trimmer test.
> 
> You should hear a ~60Hz tone in an amp. Turning the input volume off,
> mix to "loop", and the output volume up helps to hear it if it isn't
> obvious. The tone will change in volume as you adjust the trimpot. You
> may need a small screwdriver to make the adjustment, depending on the
> type of trimpot in your unit. 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.
> 
> **********************************************
> 
> hope this helps,
> kim
> 
> 
> ______________________________________________________________________
> Kim Flint                     | Looper's Delight
> kflint@loopers-delight.com    | http://www.loopers-delight.com 
> 
> 
> 

Louis Hesselt-van-Dinter