It sounds like you've got distortion with both RCA (line) and XLR (mic) inputs, right?
In that case, you could narrow it down to the ADC and/or a *single* opamp that drives the ADC.
You can debug this in your own home by:
- generating a sine wave in your audio program ("generate tone" or somesuch).
- do this at 0dB FS and transfer to your NJB3 via firewire
- plug a 1/8"<>2XRCA adapter into line out of your NJB3 and plug into RCA on your UA5
- plug the UA5 into USB port on your computer and record there
- play on your NJB3 and record the signal, adjusting the gain on your (RCA inputs) of UA5
- adjust gain so you're recording various levels, like 0dB, -3dB, -6dB.
See you if you can reproduce errors.
I've reproduced problems (different, but serious hardware problems) doing this.
Richard
no problem with the RCA line input - i have run that many times without an issue
the only issue seems to be with the XLRs which i've only used with phantom on, i will test using xlr line input as well to see if there's a problem as well
OK, just to be sure, run this *controlled* test on the RCA inputs. That will completely rule out any problem, all the way up to 0dB.
Well, if it is only XLR inputs, you've reduced it to the other two opamps
. Or the phantom power and/or blocking capacitors, I suppose. But I don't know what Chris has done with these, so it is harder for me to help there.
You can do the same systematic testing with the XLR inputs. Generate a sinewave tone in your audio program. Attenuate it by say, -20dB. Then save to the NJB3. Play on the NJB3 while recording on your computer. Try it in both the XLR and the TRS lines, while cranking the gain up to as close to 0dB as possible. You should get the same perfect sinewave out. If not, record what level and what input type (TRS, XLR) causes the problem. You could further isolate by trying balanced (TRS) and unbalanced (TS) inputs. Oh yeah, try with and without phantom power.
My guess is either a bum opamp (or solder connection) or a problem with one or more blocking caps.
Good luck!
Richard