Fantom-G High-pitched Noise

The source of interference has been found.

It is via the Firewire cable from the Tascam mixer to the Apple Mac Pro computer. (darn it to heck!)

The noise is only on the 2 channels the Roland Fantom G8 is on so the 2 returning channels (1 & 2) that the computer feeds back to the mixer do not affect the noise level; only the 2 common to the Fantom.

I have had tons of equipment flow through here and this is the only time this has surfaced and it is on the latest and greatest = ouch! Some of my toys are over 30 years old and quiet as a robot boy pretending to sleep.

The computer is plugged into a different circuit (breaker) so I will see it what can be done via trial and error.

I did unplug the computer and ran it on the back-up battery and there was still a continuous high-pitch noise coming from the speaker stacks, so I don't know if I can solve this with changing the AC plug location.

My other (older) computer is next to the Mac Pro and it does not cause the noise (of course it is not on the Firewire network either).

Any Pros or Semi-Pros got any suggestions?

Zenzilla

I will try switching from the mic/line inputs to the RCA digital out/in and have the report on your desk first thing in the morning.

Zenzilla

Is your Mac or the Tascam mixer properly grounded?

Arjan,

Yes all grounds have been checked and rechecked.

When I unplugged the computer and ran on battery, I was really surprised. That's when i chased down the Firewire as being the problem.

I'm still working on it as I type....

Zenzilla

OK = problem solved!

I switched the sound cables running from the Fantom G to the Tascam mixer from audio to digital (RCA) and this gives a remarkable clean sound and silence where silence is expected

To recap:
When using Firewire cables to connect a Tascam mixer to an Apple Mac Pro, consider using the Fantom digital (RCA) output as method of connecting the sound to the mixer.

HTH other users of the Fantom Guild.

Zenzilla

addendum:

By using (only) the digital line out, the top panel volume control knob does not govern the sound level.

The top panel volume control knob will still work on the headphones.

Zenzilla

Info addition: the noise is not static white noise, but very similar to that which is heard right before a microphone feeds back.

Further testing:
I have changed audio cables, moved computer electric AC to same wall plug as mixer/amp, and toggled thru all rack units as possible causes. I also changed the system clock from mixer (Firewire) to computer (Mac Pro).

= still the noise.

I have discovered that if I disconnect the USB cable that runs from the Fantom G8 to the computer, the noise will cease (when using regular audio out 1-2).

So I will switch out to other USB cables and also alter the route to see if I can kill this noise while running the audio out 1-2.

Stay tuned.

Zenzilla

SUMMARY:

High-pitched Noise via audio outs 1-2 on Fantom G8 [with Firewire connections ~ computer to mixer]

I turned off the Fantom = still noise

I unplugged the Fantom electric AC = still noise

I unplugged the USB cable = quiet!

I switched out the USB cable to other plugs on the computer... TADA!

When connecting a USB cable from the Fantom-G to the USB PCI expansion card = high-pitched noise!

OK = source of problem has been found and fixed

To add to this, one other device will duplicate this. If I plug in the MOTU MTP-AV into a USB plug on the USB PCI expansion card = high pitch noise. So it appears that certain internal circuits are in existence in devices that do not play well with others. I found two.

Zenzilla