On Mar 11, 2015, at 2:11 PM, Frew, Justin <jfrew@aii.edu> wrote: Hi guys... We are using an ADC brand bantam TT 96 point patchbay. When we use phantom powered microphones, we experience a significant loss of signal, as well as some noise. Also we can’t seem to get a decent amount of signal through our external pre as well (Universal Audio 610). When bypassing the patch bay and panel ties, we get signal just fine. The patch points are fully normalled for convenience, however when using condenser mics, we need to manually patch through the normal for us to even get a weak signal... Very strange, I Know! Just wondering, have you guys ever experienced patchbay users encountering these kinds of issues where phantom power is involved? We are continuing certain tests to rule out exactly where the issue is stemming from, but thought it might be useful to pose the question to you guys as well. Please do let us know if you have any information regarding this.
Thanks and best wishes,
Justin Frew Audio Technician jfrew@aii.edu P 778.373.8993 C 778.846.2291
There is no “we” here sir. Just me… Bob Hickey - Mister Patchbay. Anyway your problem is that your ADC does not have the grounds normal from the top-row to the bottom-row. The standard ADC normal has only the tip & ring normal. Therefore your Phantom mics are not seeing any ground. That’s why when you use a patch cable it works correctly because the patch cable is connecting the ground from the top-row to the bottom-row. There are three ways to correct this. 1. Strap all grounds together. 2. Strap the grounds from the top-row to the ground posts on the bottom-row for each mic channel. 3. Send the patchbay to me and I will fix that for a small charge.
Bob Hickey, you are the man! It all makes sense now! I believe that the problem is that I didn’t normal the grounds.. Doiiii! Thank you very much for your help, you are a life saver. I’m going to go with option 2 J Thanks and best wishes! Justin
