EHX Poly Chorus: Problem - overloading

[frank_p]

Hi,

I bought an Electro-Harmonix yesterday and I wondered if anybody had an idea about how to solve a problem:

The effect in question is often overloading at normal volume level (humbucker directly in the effect).  The "overload" LED light goes "on" continuously and I get a slight clipped output. 

Is there anything you guys know about how to solve the issue ?  I noticed also that on harmony-central someone complained about the same problem.
When I plug a "closed" buffered Boss pedal in front of it, it goes worse. And when I use hot humbuckers it's also more noticeable.

I opened the box : there is a lot of trim pots in there, I don't know if there could be some for input and output volumes.

Also, strange thing, the red wire at the input jack was not soldered...  Only placed in the hole of the tab.

If it's not a trim pot adjustment problem, could there be a simple mod for this problem (not the wire problem... the overloading one  ) ?

Thanks !

F-H

[mongo]

I had a similar problem with my deluxe memory man a year ago or so out of the blue it started overloading...

after much tinkering I realised that  one of the 3 leads of a component was detached from the actual thing, I don't have my DMM in front of me but  I remember the part being a 125 something... if I remember well it was some kind of regulator... hope this helps!

Andy

[frank_p]

Hé ! Merci Mongo.

Maybe I should try one other at the store to see if it does the same...  When I play softly it's OK, but I can't go too crazy on it.

Just don't know what to think...

Ça va par chez vous les inondations ?

F-H

[frank_p]

Also:

quote from HC
--------------
The bad stuff, the pedal is not true bypass and does what is commonly known as "tone suck" and volume suck (probably due to the percieved treble loss) when in bypass. Now I true bypassed my polychorus and was greated by a HUGE volume drop. I decided instead of increasing the gain of any of the gain stages or tacking on a gain recovery stage on the output. I would return the pedal to "stock" and just use a clean boost at a set level in a true bypass box loop. Which also has the added benefit of a feedback loop, which makes for great noises.
--------------

Same problem here:
http://www.diystompboxes.com/smfforum/index.php?topic=730.0

I feel like this also:

hmmm, @#$% this is going to be a complete bastard to trouble shoot...........

It overloads in bypass mode also...

Schematics:
http://electroconducive.googlepages.com/EHXEchoflanger-FactoryPG1.jpg
http://electroconducive.googlepages.com/EHXEchoflanger-FactoryPG2.jpg

Some more info from Mr Hammer:
http://www.diystompboxes.com/smfforum/index.php?topic=22128.msg138791#msg138791

I wonder if an external true bypass sw, a volume pot at the input and opamp at output would be a good thing in the "case" of this effect...


F-H

 

[bumblebee]

My polychorus LED overloads all the time, don't wory about it man cause most of the trapezoidal EHX effects overload and operate perfectly normal.

[frank_p]

My polychorus LED overloads all the time, don't wory about it man cause most of the trapezoidal EHX effects overload and operate perfectly normal.

Ouf ! Thanks man !  I didn't want to go try them out again at the store.  The damn thing is new, opened and and I was begining to probe around.

Eeeh... I don't know what trapezoidal mean for effects...

I think you saved me a lot of time.
Thanks a lot.

Now I have to think what to do with the problems of this effect.
New projects.

[bumblebee]

no problem.trapezoidal is the shape of the side of the polychorus box. the big boxes, most of them have overload LEDs and they all flash with input signal.

[frank_p]

Cool!  Tx