I've had a strange problem the last 2 shows, and I'm not pleased.
Running LSD2 > Hydra > W+Mod UA-5 > optical > H120 and then at some random point part way through the show the right channel level will go nuts.
It starts off with a moment of silence, then it pegs. See pictures and MP3 sample below. I've run this combination before without problems. Nothing physical is happening when this occurs that I know of. Nothing obvious like someone tugging on wires etc.
I think I can rule out the optical > H120 piece. At the same time as this sample occurred I was pulling another patch with UA-5 > gray box > optical > JB3. The JB3 has the same glitch so it must be upstream from there. The new Hydra cable looks good... I inspected the solder joints, and it looks fine. I set this all up at home to see if I could repeat it. I could not. I wiggled the cable ends at the UA-5 and the mic, no hiccup.
The difference? Well one difference is heat... At home it's layed out on a table, at a show I had this all zipped up in a padded "beer proof" backpack, running from a 12v SLA. I think whatever heat the UA-5 generates is pretty will insulated. I've always run my UA-5 that way... but I used to run non-phantom power Naks, and with a 9V Lion battery. I suspect 12v generates a little more internal heat than 9V does, and phantom power conversion generates heat. I wonder if all these little differences are enough to make a difference. This particular UA-5 is "new to me", but I have no reason to doubt it.
Simple question.... is this a known problem? I hadn't heard of it.