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RE: PANIC! Echoplex freaks out

At 1:44 PM -0700 6/20/98, Douglas Lawrence wrote:
>I think the fact that our problem is the same is not just coincidental. It
>seems Oberheim (and others) say that *any* 30-pin memory is good to use in
>the 'Plex (parity or non-parity). Somehow I doubt that, but that's just 
>my experience in the computer industry where memory is very hardware

I don't think its very fair to imply some sort deceptive tactics on the
part of Oberheim or any other manufacturer making such a claim. Until this
email thread and another mail I got this week, I've never heard of anyone
having such a problem with a particular type of simm on the echoplex, and
it's been out for 3 1/2 years. (5 years if you count the Paradis LoopDelay,
which had a similar memory controller design.)  I'm pretty sure I would
have heard about it if there had been a problem! In the past, all the
different simm types have worked just fine, so there is no reason why
Oberheim wouldn't tell their customers that. If you've come across a vendor
selling a type of memory that doesn't work, you would serve the world
better by contacting Oberheim and letting them know about it. Then they
will be able to inform their other customers, as I'm sure they would be
more than happy to do.

My experience as an EE designing products for the computer industry and the
music industry is that the ordinary DRAM typically used on 30 pin simms and
the simms themselves only come in just a few basic varieties, and that it
is pretty easy to design a memory controller that handles them all. That's
what the echoplex and other memory oriented music products do, which is why
manufacturers say they handle all types of simms. The echoplex memory
controller was designed to handle parity/non-parity simms, any speed faster
than 120ns, and all the different possible DRAM chip configurations. When
we designed the echoplex, we tested all the varieties available and
everything worked fine. And as I noted, no problems have been reported to
Oberheim since, at least that I know of. It's possible you guys have come
across something new, which Oberheim should be informed about.

In the days when 30-pin simms were common on computers, some computer
manufacturers elected not to use universal memory controllers for their own
mysterious marketing / cost / bad-engineering reasons. That tended to
confuse people buying for music industry products, where manufacturers
tried to do their customers a favor by going to the extra effort to do it
right. Unfortunately, various memory vendors and music stores have been
known to take advantage of this musician confusion and sell "special"
memory for a higher price, which is almost always BS.

With newer computers the situation does get more complicated, since newer
DIMM memory comes a wide range of flavors and you really do need to make
sure you are getting the right kind, because the technology is quite
different. But that generally wasn't the case in the 30-pin simm days. And
it's generally not the case for products still using 30-pin simms now. But
it does add to the confusion, unfortunately.

It seems to me more likely that somebody is either dumping defective memory
on the market or somebody is suddenly making 30 pin simms with a different
type of DRAM on them to clear inventory. (either of which would not be at
all suprising given the current economic crisis in South Korea, where
Samsung is located. A lot of ugly stuff has been happening in the past few
months, because companies in SE asia are doing anything to get dollars into
their bank accounts as quickly as possible.) It might be wise to buy memory
from reputable dealers to avoid these problems, at least for now.


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