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Hi mark,
no, this is deffinatly just a ground loop.
I have included afterr my sign off the email from Andy Ewen (spelt it wrong first time, sorry andy)
I have always found it odd that a guitar going into an echoplex going into a pa system is considered by gibson to be an unusual "certain situation"...i have wrote a few times to confirm this but apparantly this is so.
can any other UK looper test this out on a black face and let me know the results
no DI and into an amp or pa with a standard uk grounded plug.
Anyway mark, the problem you are having may be to do with a resistor drifting out of tollerance, its rare but i have heard it....if it happens on the gain staging it can cause the input to be recorded too high and distort on output.
is it happening just on the loop? not on the direct signal?
Phill
Hi Phil,
The mains filter is a standard part fitted to all Blackface EDPs. The problem you have is a known issue and all Blackface EDPs will do this under certain situations, (i.e. yours).
It is caused by the fact that when I re-designed the unit for CE approvals and EMC testing, they made me ground the PCB in 9 separate places instead of the original 1 position. This causes an earth-loop when certain other equipment is used and as you say, can be eliminated by removing the earth from the mains lead, (not a good or safe practice).
However, I found a solution which is to send the output from the EDP via a DI box, specifically one that has an isolating transformer in it. This effectively removes the ground loop and the Blackface should then be quieter than the older White ones.
I informed Gibson of this issue and suggested we send a DI box out with every unit but they weren't into the idea and just told me they would deal with any problems in the field if and when they arose. Funnily enough, out of the 1000 or so Blackface ones we made and have been sold, you are the only user to find the fault!
Just get yourself a half decent DI Box. One of the ones below will probably do the trick, (the second one will almost certainly work as it has a transformer in). I tried several when I was experimenting and they all worked but I can't guarantee everyone will. You might want to borrow one of someone and then if that model works, buy your own, (or steal it from them :) From: mark@markfrancombe.com Date: Wed, 3 Mar 2010 20:22:04 +0100 Subject: Re: anyone want to swap their Beige EDP for a Black EDP Pro Plus To: Loopers-Delight@loopers-delight.com No Beige to offer Im afraid Phil, but just out of interest, what IS the issue with your Blackface exactly... is it ground hum? Cos my newer unit suffers from distortion (or noise depending on how I set the input knob) I cant quite seem to get it right, and after all these years Im still not very sure of the technical side of things... My Old EDP is a horse... I can stick anyting into that it neither hisses or distorts.... so its a bit weird... Im kinda used to it now actually, infact the distorty EDP is usually my "lead" looper, whereas the other is the bass, rythum and clean stuff looper... Mark On Wed, Mar 3, 2010 at 5:18 PM, phillip wilson <phillwilson@hotmail.com> wrote:
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