A pair of toasted A/D boxes ... why?

[Mystic]

Hi folks! I have a Lucid ADA1000 and a Symetrix 620 (both outboard 20 bit
A/D converters, with the Lucid also having a D/A side). Both were working
just fine a year ago when I last used them. I've also had a Gina 24/96 on
my computer for the last couple of years, and use its S/P DIF input to bring
signals in from either of the outboard units.

I recently tried using both of the outboard converters again, and now it
seems they both have developed problems, although not of the same type. The
Symetrix 620 A/D is introducing random 1-sample-wide pops and clicks into
either one channel or both channels (exactly how many are introduced seems
to vary a bit each time that I turn on the 620's power, but it's always far
too much to effectively filter out). The Lucid A/D on the other hand is
creating what sounds like heavy square wave distortion on all signals (even
low level ones), and is even more useless than the Symetrix.

I'm quite puzzled about this. The units haven't been transported or
anything, and are stored in a smoke-free, constant temperature environment.
I've been very diligent about unplugging them (along with everything else in
the studio) anytime a lightning storm is anywhere in the vicinity. And why
would my two A/D converters go bad when all of the other 20+ pieces of
equipment on the same electrical circuits seem to be fine? (I don't *think*
there is anything wrong with the Gina card's S/P DIF input because I can
still use it to bring in digital audio from my Line 6 Pod Pro amp simulator
and not have any such problems. Also, it may be worth mentioning that the
D/A portion of the Lucid still seems to work fine.)

What I'm wondering is:

1) Are A/D converters particularly sensitive to something that would have
made both of these start having problems after the same period of unuse?
2) Might either of these units be salvageable, before I throw up my hands
and just replace them (when finances permit, that is)?
3) Is there another possible explanation that I haven't thought of?

Any thoughts that can keep me company while I stare in disgust at my newly
out-of-service studio would be appreciated.

- David




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[Mike Rivers]

In article <3f4d21d8$1_6@corp.newsgroups.com> mystic_fm@excite.GOAWAYSPAM.com writes:

> Hi folks! I have a Lucid ADA1000 and a Symetrix 620 (both outboard 20 bit
> A/D converters, with the Lucid also having a D/A side). Both were working
> just fine a year ago when I last used them.

> I recently tried using both of the outboard converters again, and now it
> seems they both have developed problems, although not of the same type. The
> Symetrix 620 A/D is introducing random 1-sample-wide pops and clicks into
> either one channel or both channels (exactly how many are introduced seems
> to vary a bit each time that I turn on the 620's power, but it's always far
> too much to effectively filter out). The Lucid A/D on the other hand is
> creating what sounds like heavy square wave distortion on all signals (even
> low level ones), and is even more useless than the Symetrix.

Are they connected in the same way to the same equipment that they
were the last time you used them? Something must have changed? Has
everything remained in place and you just didn't use the studio for a
year? Different cables? Different sources? Different destination?



--
I'm really Mike Rivers - (mrivers@d-and-d.com)

[Bob Smith]

Mystic wrote:
>

> I recently tried using both of the outboard converters again, and now it
> seems they both have developed problems, although not of the same type. The
> Symetrix 620 A/D is introducing random 1-sample-wide pops and clicks into
> either one channel or both channels (exactly how many are introduced seems
> to vary a bit each time that I turn on the 620's power, but it's always far
> too much to effectively filter out). The Lucid A/D on the other hand is
> creating what sounds like heavy square wave distortion on all signals (even
> low level ones), and is even more useless than the Symetrix.

Who is master and who is slave? The Symetrix 620 wants to be clock
master. It has no external clock input. If you don't slave the Gina
S/PDIF inputs to the 620 you will get slippage which can result in
misplaced samples. I'd also check the clocking master / slave
relationship with the Lucid and Gina. They may not be locking correctly.

bobs

Bob Smith
BS Studios
we organize chaos
http://www.bsstudios.com

[Mystic]

"Bob Smith" <rsmith@bsstudios.com> wrote in message
news:3F4D75BA.2D3F5A1B@bsstudios.com...
> Who is master and who is slave? The Symetrix 620 wants to be clock
> master. It has no external clock input. If you don't slave the Gina
> S/PDIF inputs to the 620 you will get slippage which can result in
> misplaced samples.

Indeed it's been worse than that in my case - if I have the Gina set to
master I don't get any audio at all from the Symetrix (I don't recall what
the Lucid does in that situation, because I usually favored the Symetrix for
input). So yes, all of the prior usage of both of these converters have
been with the Lucid or 620 (whichever was hooked up) acting as the clock
source.

But that is one thing I had considered as a possible problem, nonetheless.
Is there a good way to actually check/verify clock sources and/or sync? All
I have to go by at this point is the external clock setting on the Gina's
software console window (the "S/P DIF" clock option lights up when I switch
on or hook up the outboard converter, so I assume that setting is the one to
have the Gina slave to the external clock).

- David




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[Monte P McGuire]

In article <3f4d9f1a$1_6@corp.newsgroups.com>,
Mystic <mystic_fm@excite.GOAWAYSPAM.com> wrote:
>But that is one thing I had considered as a possible problem, nonetheless.
>Is there a good way to actually check/verify clock sources and/or sync? All
>I have to go by at this point is the external clock setting on the Gina's
>software console window (the "S/P DIF" clock option lights up when I switch
>on or hook up the outboard converter, so I assume that setting is the one to
>have the Gina slave to the external clock).

The type of error you describe sounds exactly like a clocking problem
though, so I'd go through all of the connections a second time and
make sure everything is right. Maybe a connector isn't seated right,
a cable has been pinched or mistreated, or something mundane like
that. Double check that your interface card is actually clocking to
the output of your converters, and not to something else that also
happens to be running close to the same sample rate, like your CD
player or DAT machine.

Aside from that, yes, things could break, but your symptoms sound like
a classic 'free running receiver' problem that it's worth spending
time to definitively eliminate that possibility. Perhaps try
different cables... plug and unplug all of the connections... etc,
etc.


Best of luck,

Monte McGuire
mcguire@theworld.com