- March 15, 2013 at 12:18 pm #15276
Hello Ted and all. I have a VC2 that I use regularly in my studio for vocal tracking. In a session last night, it suddenly stopped working. The unit still powers up but will not pass audio through the mic input and there is no action on the meter. If I plug the mic into the line input, I do get a low level signal as one would expect.
This is with a dynamic mic so I know it’s not a phantom power issue. The mic and cable check out OK on another preamp. Are there any known issues that would cause such a failure?
KeithApril 19, 2013 at 4:29 pm #15780
Hi Keith, this is an odd one….. is there a front panel jack on this model? I can’t remember. If there is then that is where the problem is. If not, drop me an email.April 22, 2013 at 1:14 pm #15781 Hi Ted. There is no front panel jack. I noticed that the phantom power started to get noisy (sounded like 60 cycle hum) about a week before it stopped working. I thought at first the 48vdc failed but dynamic mics do not work either. When it failed, there was no pop, bang, buzz or any other noise, it just stopped passing audio and there is no action on the meter.
On Saturday, I dropped it off with a local tech along with your hand-written schematicApril 22, 2013 at 8:31 pm #15782
Hmm, sounds like a failure of the input capacitors on the input stage, it’s likely that replacing them will fix it.
But let’s see what your tech says.
TedApril 24, 2013 at 7:46 pm #15783
The tech got it working. Says he thinks it was some oxidation on the TRS insert which he cleaned. I never use the insert so I can see how the contact could be broken from oxidation over time. Wouldn’t this also affect the line-in as well?May 14, 2013 at 5:50 pm #15784 Yes, this will probably affect line in as well….. it’s a common fault, but reasonably easily fixed.
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