High pitched noise from my classico or could it be something else.

[jazzyvee]

I had a gig yesterday and took the classico, after the gig the bandleader (sax player) told me there was a high pitched sound coming from my bass. I'm assuming it's the bass as he said when we were sound checking the sound guy muted my channel and the sound stopped. However he did say that it was not in the monitor which was odd. I didn't hear any noise but then most of my eq was towards the warmer end of the spectrum.



I have only heard high pitched sounds from it when I have my mobile phone near the bass when practicing at home. But other than not i haven't heard any artefact in the sound. But I accept that the pitch of the sound may be above my hearing range and the guy reporting it to me is in his early 20's.


So other things to consider is, 1. I used a new (to me) bass head Reidmar 250.
2.  whether other musicians close to me had mobile phones in their pockets. (Mine is always off on gigs).


Any suggestions that I could try to confirm whether the issue is with the classico bearing in mind I may not be able to hear that frequency.
 

[edwardofhuncote]

Could it have been the DI output of the head?


That the noise wasn't in the monitor is odd.

[keith_h]

How were you DI'ed to the console? The amp's DI or an external DI? If the amp Post or Pre EQ? Ground lifted or not? Phantom power from the console on or off?

Depending upon how the console/monitor is setup the fact that it could not be heard in the monitors could be a red herring. If the monitors were EQ'ed on their own it is possible the settings cut the frequency of the noise. 

Not knowing what they meant by high frequency or the configuration it is hard to say what the cause might be. It would have been nice if they had taken the time to diagnose the signal chain a little better so as to isolate where the noise was being injected. I'd try switching DI's to eliminate those as the source. If the ground was lifted when it isn't needed that could result in the external signals getting through shielding. I've seen phantom power not play well with some amplifier DI's. Unless you can reproduce it at this point it is really just a guessing game. 

[garyhead]

Ron completed the first RF upgrade for Classico’s in 2019 and installed it in mine.  Ask Mica if the upgrade is modular and you can get it done in the UK.