Pro Tools Users - www.ProToolsUsers.Org - Home of the Pro Tools Community

I first started recording years ago on a Roland VS-880, and I would jack out from the headphone jack on the Roland into my Alto HPA6 Headphone Amplifer; worked fine.

Using the same cable - I jacked from the Mbox headphone jack into my Alto - now I pick up a high-pitched sound. It's not in the recording or my playback, if I listen with headphones on the Mbox; I'm picking it up in the routing.

I tried several cables - all the same problem. Am I doing something wrong? We're talking about 18" to 2 feet of cable.

Do I need to come out of the Mbox from somewhere besides the headphone jack?

It could be a feedback problem. If you're going into a headphone jack the added amplification could be caused a feedback loop to occur through your speakers or microphone. Just an idea off the top of my head.

I don't think that's it - no speakers were connected at the time, and no mics. We were just mixing some tracks and my buddy wanted to give his input - hence the headphone amp.

I am definitely not a "techy", but it sounds like it might be an impedance matching problem. If you have the manuals for both devices you could check their input and output impedances.

I don't believe the mboxes have a very robust headphone output. You might try going line out to the headphone amp (if it can accept a line input) instead of using the mbox headphone out.

I'm gonna try that; and I'll get back to everyone here. If anyone has any more ideas - please continue sending.

hi there

it sounds like an earth problem....try taking the earth off the vs 880...i get it on mine too its definetly a grounding issue steming from the computer i have greatly reduced it by juggline one or two things around on the mixer.....like you say its not on the recording thank god
good luck