AKSO

Hi

Yeah I never mentioned the speakers. Truth be told, I need to get new ones but that’s on the shopping list for now. I currently have an old 5.1 logitech x-530 setup. I connect them with an unbalanced phono cable that goes straight in the mixer. I’ve excluded them as a noise source altogether for two reasons. First, I can hear the buzz in my headphones even when the speakers are not plugged in. And second to answer 1), there isn’t any buzzing when the speakers are turned on, volume all the way up and not plugged in the mixer.

Also, everything that I am using should be grounded properly as my whole setup including the extension lead was PAT tested a few months ago.

I ran some additional tests today focusing on the points that you’ve mentioned in your post and found some interesting stuff.

So, I got my old mixer, which is an analog Numark M2 and started compering setups to see what happened. I connected the mixer straight to the speakers, no CDJs were plugged and found the following. The Numark was completely silent.No matter what I pressed or moved there was no noise. Then I plugged one CDJ – usb straight in the laptop (running on battery) and RCA in the mixer. And the problem came back. A buzz when I link the CDJ (press the usb button), which goes away when I move the pitch fader or unlink (press the usb button again) the CDJ. Then I tried the Behringer mixer I have. Again, only the mixer to the speakers. Now, channel 1 and 2 were completely silent, channel 3 and 4 give a bit of buzz. Considering that everything was turned all the way up, I can live with that. I can also hear the buzz in my headphones and interestingly enough the pitch of the buzz changes slightly when I turn them up and down. I suppose the mixer is not the best but again, I can live with that (for now). Everything else was the same when I plugged the CDJ. I also tried all CDJ with different RCAs and USBs and power leads.

No buttons/knobs on the mixers affect the buzz. When the CDJ is not in usb mode there is no noise, once they are recognised as sound cards the buzz comes back and is also channel specific. If I turn the fader/gain trim down the noise goes away.

Am I right to think that the issue comes form the CDJs themselves and this combined with the mixer creates the whole issue. Also I didn’t do that today but historically I’ve notices that when I connect my Maschine to channel 4, it gives a very high in volume buzz. I give this to the cheap sound card that I am using with my Maschine and to record (another thing I need to upgrade). Some hum eliminators are actually helping with that at the moment but I’d like to fix the problem centrally.

Any other suggestions?

Cheers