I have a Lexicon Alpha audio interface that I use for recording samples and mixes from CDs, records, etc. Recently I tried to rip another one of my records to mp3 using Audacity on the Mac as usual, and I get some really loud distorted noise on the left channel. The right channel sounds fine, but quieter than usual.
I tried swapping USB ports and cables and still the same thing. Then I plugged my headphones into the headphone monitoring jack of the Alpha, and listened in while it's recording, and everything sounds fine there. Also, if I connect some audio cables from the Alpha's stereo out to the computer's line-in, it sounds okay there too, sans the quiet hiss you usually get from the line-in recording.
It seems like the USB port of the Alpha is somehow not working and sending in bad data to the computer. Is the Alpha messed up for good? Anything else I can try to isolate the problem?