Oscillating noise? Troubleshooting

[alex1fly]

Troubleshooting and posting this all around.

I have a Spark practice amp that I use for low-volume practice at home and for monitoring at gigs. Sounds great, no issues, etc. I just picked up a Fractal FM3 last week. The Fractal FM3 into my other guitar amp or headphones sounds great. The Fractal FM3 into the Spark, however, has the addition of a high pitched oscillating noise. Like the background sound of a phaser pedal. It happens on every single patch and the oscillation seems to coincide with a blinking LED on the Spark. The Spark, Fractal, and extra guitar amp are all plugged into the same APC surge protector.

Any thoughts? I hesitate to reach out to the vendors because I feel like they'll just point fingers at each other.

 

[Mincer]

Are you hitting the input of the Spark with too much output of the FM3? My FM3 has been silent with anything I plug it into.

 

[LLL]

First thought that comes to mind is an improper ground loop with the connection between the two.

But don't quote me on that...

 

[LLL]

Or, could be line level signal versus instrument level signal issue.

 

[jeremy]

First thought that comes to mind is an improper ground loop with the connection between the two.

But don't quote me on that...

that was my first thought too but dunno anything about a spark

 

[alex1fly]

Thanks all. I'm still not sure what's going on, but I was able to get rid of the noise by using a TRS to TRS cable. I *think* the FM3 wants a TRS jack in its output. Fractal kind of confirms this in the FM3 manual, and Fractal's "humbuster" cables have a TRS side for the Fractal gear and a TS side for the power amp or whatever you're plugging into.

TS/TRS and balanced/unbalanced are things I've never had to deal with... but pro audio is rife with these things so I guess I'll get on board.