Re: MY ECHOPLEX IS BROKEN

[kflint@annihilist.com (Kim Flint)]

Hi Andre-

Having a good day, are we?

I don't think there is anything wrong with your unit. You see, the echoplex
has a noisegate built into it, on the signal path to the loop. (not the
direct path) This is actually a feature, and serves a very useful purpose
in making Undo much more useable.

The Undo function is actually quite a bit more complicated than it might
appear. It has some intelligence built into it to prevent unnecessary
memory consumption in the event that overdub is on but there is no actual
audio input. (happens a lot more often than you might think!) So rather
than writing a whole new section of memory with essentially the same thing
that was in the last section, we detect this and jump back to the existing
section.  This also makes undo more musically useful, so that a press of
undo will remove an actual overdub rather than a pass of inaudible noise.

In order to differentiate between miscellaneous noise and actual
intentional overdubs, we have a software based noisegate. The threshold for
the gate is set quite low, since its only supposed to deal with noise. If
your input and output gains are set right, you shouldn't be tripping the
gate with intentional signals.

So I think your problem is that you need more gain on your input signal.
Perhaps when you dropped the poor echoplex on its face, the input volume
position got changed a little? Try turning the input volume up a bit, and
the output volume down a bit to even it out. That way, the quiet passages
should have enough amplitude inside the echoplex to be above the threshold
of the noisegate, and still sound quiet when played back.

Improper gain settings might also explain the noise you are hearing. If you
have somehow managed to set the input volume too low and the output too
high to compensate, you have effectively reduced your signal to noise
ratio. You will also hear more artifacts from the analog to digital
conversion process, because the lower signal levels will be using fewer
bits to represent them digitally. The result is a greater amount of what is
called "quantization noise."

One new feature that will appear in an upcoming upgrade is the ability to
control the threshold of the noisegate, as well as a generally smarter
gate. The current threshold setting is optimal for most cases, but there
are times when a higher or lower threshold might be useful. For instance,
very high gain guitar signals are likely to have a fairly large amount of
noise and the optimal threshold setting for the gate would be higher. In
your case the optimal setting might be a bit lower. But really, the
difference would be quite subtle. If you are actually noticing audio
dropouts from the gate as much as you seem to be, I think we've got a case
of incorrect input/output gain settings.

Give it a try, and let me know how its going. You've got my number,
obviously.....:-)

kim



>That's right, the thing's on the fritz.
>
>When recording a loop, say, one note, the note will decay at a relatively
>normal rate, but then suddenly cut completely out after falling below a
>certain lvel.  I've tried this in several different modes, with and
>without threshold, and nothing helps it.
>
>I'm also noticing quite a bit more digital noise on the looped sound
>during recording and playback than I previously have.  I had previously
>been unable to tell the original signal from the loop, but there's now
>quite a bit of aliasing I can hear.
>
>Can Kim or anyone else *please* send me any information that can help.  I
>am UNDER NO CIRCUMSTANCES prepared to send the unit to Oberheim, since it
>has been well-documented on this list that they have had very poor
>customer relations and have in some cases kept Echoplexes several months
>without communication.  I'll take the unit directly to Kim for work if
>need be (and if possible), but as my previous post mentioned, I have a
>very impotant gig coming up, and if I cannot get the Oberheim repaired,
>than I'll be forced to cancel the performance.
>
>Unfortunately, I'll also be forced to seriously reconsider the long-term
>feasibility of trying to work with what increasingly appears to be a
>highly bug-ridden machine with no official support available to it.  So
>again, if anyone can offer help, then please do.  Otherwise, my days with
>the Echoplex may be seriously numbered...
>
>--Andre

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