Line Noise

[mharris5]

Hi,

My friend and I are currently trying to make some recordings. After setting up the studio and purchasing a PreSonus Inspire 1394 4x4, we tried to record a direct line feed from the guitar amplifier pre-amp output.

While doing so, we encountered a consistent high pitch background noise. I tested multiple amplifiers and, whether on or off, the noise persisted constantly (I also tested multiple cables). In the end, the only thing that stopped the noise was unplugging the amplifier and, after testing the microphone input on the Inspire (which worked fine), I concluded that the noise was originating from the power line itself.

I have tried using a spare Belkin CleanPower bar, which seems to help a bit, but there is still a great deal of noise coming through the line.

I was wondering if anybody could provide information on a more effective way to filter the power or maybe have any idea if anything else could be causing the noise.

Cheers

Matt

[Electriclight]

after testing the microphone input on the Inspire (which worked fine),

What does this mean? You plugged in a microphone and there was no noise. How does this prove it is the power. More commonly, the problem is guitar shielding issues. What kind of guitar is it. Single coils or humbuckers.

Does the noise persist if the instrument is unplugger fromthe amp?

Is all the equipment grounded? Are they all plugged into the same power source / wall outlet? Are there any flourescent lights, or CRT monitors nearby?