Topic: Rythmic Signal Spikes

[kcmule]

Hey guys,

I went to tape Shannon Curfman on Tuesday and expierenced
some abnormal signal spikes for part of the show.  I also taped
the opener (Random Tuesday) but did not have any trouble at
all.


My rig that night was AKG 483 > Tmod UA-5 > JB3 @ 48

I ran for more than an hour, taping the opener, and did not
notice any problems whatsoever.  When the opener was done
I shut the power down on the gear and fired it back up for
Shannon when she came on.  Taped about 15 minutes of her
set then noticed the peak light on the UA-5 was flashing every
few seconds, but this wasn't normal peak light activity it stayed
lit up for longer periods than normal (seemed like about a second
and a half)

The right meter on the JB3 was pegged each time the light went
on even with the gain all the way down on the UA-5 for the right
channel.  Even between tunes, the light kept flashing.  After
checking mic cables, optical cables, power cables, etc...  I finally
said fuck it, lowered the stand swapped out the hyper caps for my
set of cards mid-tune. After swapping caps the problem disappeared

I've got the 483's setup in the living room running for almost threee
hours now and no sign of problems.

Anyone got a clue as to what the problem could be?

[kcmule]

Here is a small snap-shot of the wave form.
Odd to say the least.

[momule]

Could someone post a link to the known problem with 480's and a set screw (or summpin like that)
I was trying to explain it to him the other day as a possible cause.

I tried to find it myself but was unable to do so.
Nick

[anodyne33]

 

[kcmoejoe]

Could someone post a link to the known problem with 480's and a set screw (or summpin like that)
I was trying to explain it to him the other day as a possible cause.

I tried to find it myself but was unable to do so.
Nick

Is this the thread?

http://taperssection.com/index.php?topic=9982.0

[bluegrass_brad]

my first guess would be a cabling issue, especially since it wasnt recreated when you tested at home.

[SparkE!]

What did it sound like?  (Got a clip?)

[kcmule]

Sample attached.  Almost sounds like thumping the end of the cap.

[anodyne33]

FWIW I've heard that noise many a time when turning phantom on or off while a mic is up. If it was rythmic my guess is that you have a bad cap in the phantom supply of the UA5. That could also explaing why it didn't happen for the opener and hadnt happened yet in your living room test, that is, if the cap is slowly diminishing (or increasing?) it's capacity after some time being charged. Of course, it very well could be something else in your signal chain (cables/bodies/caps) reacting violently to the 48+ also.

Would somebody who knows what they're doing please try to turn what I just said into something sensible.

[kcmule]

I'm not real sure what to think about the problem.
Guess I'll keep running it and see what happens.

FWIW, one of my set screws on the body was about
an 1/8 of a turn loose.  I've let this thing run for more
than seven hours now without problems.  Even turn
the phantom on/off every once in a while just to give
it a work-out like it would get at a show.  Just odd.