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Re: Echoplex problems -- help

At 4:23 PM 12/6/96, Henry I. Bornstein wrote:
>I'm having two problems with my echoplexes. Any help would be greatly
>1)  If I try to use Brother sync between the two machines, it works for a
>but then crashes and one or both machines lock up.  I talked to someone
>who said
>there was a hardware update available that might solve this.  Has anyone 
>this problem, and does anyone know about this hardware update?

I know a little about the hardware updates, yes. I redesigned the brother
sync circuit to make it more reliable just before I left
G-WIZ/Gibson/Oberheim. The redesign never got implemented in production
units by Oberheim. It is possible to mod existing units with the change,
but it does take a bit of effort. Its not as simple as just changing a
resistor value. You have to hack a couple of transistors in series with the
outputs of the BrotherSync jack and add a couple of resistors. With this
particular mod, the Echoplex will always power up and stay running
regardless of what happens to other units connected with BrotherSync. This
fixes problems where sometimes a unit would crash if another BrotherSynced
plex was turned off, or where the plex wouldn't power up right when other
units on the Brother chain were powered down. These problems almost never
showed up with two units, however. It is more common when you have three,
four, or more connected. Even if you do experience this particular problem,
it's not fatal. Once you have them all on, just turn the one that crashed
off and back on and things should be fine. Its irritating, and the mod
fixes it. If anyone is interested, I could probably put some documentation
about how to do this one on the web site.

Another mod that should be in the later production units, was a resistor
value change that came courtesy of Chris and Anton Chovit's troubles with
BrotherSyncing all their echoplexes together. The original design only
allowed three units to work together, but by changing resistor R62 from
2.2K to 10K, you should be able to sync 18 echoplexes or so without any
trouble. I'm pretty sure that nobody actually owns that many, so that
should be good. I suppose if you really need to BrotherSync even more units
at some future echoplex user convention, R62 could be increased even

You're particular troubles sound related, but different. Do you have one of
the very first set of production units? You can tell by looking at the
serial number. I think the first unit was EDP1001, and they went up
sequentially from there. I made some value changes in the BrotherSync
circuit after the first production run, which means the first 50 units or
so probably have the oldest version of the circuit. In this case, the mods
corrected problems where plugging and unplugging a cable in the BrotherSync
jack while the power was on could cause the unit to crash. It's possible
that these changes could have fixed problems similar to yours, but I'm not
sure. If you have one of these early units, let me know, and I can tell you
what values should be in the BrotherSync circuit. I should put this on the
web page anyway.

I've never seen BrotherSynced Echoplexes crashing spontaneously after they
had powered up successfully. It was always power-up/down or
plugging/unplugging which caused it. You are using the right kind of cable,
right? A stereo/TRS type?  If that's not it, I suspect you have something
wrong with one of your units. If you have one of those early units, the
first thing I would suggest is changing the various resistors and caps to
the right values. Another idea is to get in there with a soldering iron and
fix any solder joints that look cracked or cold. (assuming you know how to
do minor electronics work. If not, find someone who can help you out.)
Something like that in the BrotherSync would definitely cause intermittant
crashes. If that doesn't do it, we can try the transistor mod. And if that
doesn't do it, we can swap components til it works. I seriously doubt it
will take that much effort, though.

One thing I don't recommend doing is sending it to Oberheim, since they are
a bit short staffed these days. It may be a while before you get it

>2) I've been unsuccessful in attempting to archive loops by sending them 
>Midi Sample Dump Standard to a MAC computer running Alchemy software.  I
>am able
>to send the sample to the computer successfully, but when I attempt to 
>it to the Echoplex, I get an error message that says "insufficient 
>I"ve got plenty of memory in the computer, and this has happened for the
>shortest loops when the echoplex had 120 secs of free memory. From what I 
>tell, the Alchemy error message is the one that comes up if the sampler 
>is out
>of memory, as I have been able to reproduce the message when I attempt to 
>to another sampler that is  fully loaded.    Has anyone been able to 
>from a computer using SDS?  It would be great if I could get this to work.

SampleDump is another can of worms. The problem here is with the Sample
Dump "standard" rather than the echoplex. No one seems to follow it in
quite the same way. If Eric is reading this, he can tell you more about
whether there is a problem with Alchemy. During development, we found all
sorts of different variations among different manufacturers, not to mention
some that had bugs. We did our best in the first soft version to work
around the ones we found, but we definitely didn't get to everything. The
update, which is creeping ever closer to the light of day at glacial
speeds, has a much more sophisticated SampleDump implementation which
should handle everything (I hope!). I know for a fact that the shipping
software works fine with Sound Designer and Studio Vision. Try those if you
can't get Alchemy to work.

hope this helps.


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