The Secret Society of Lathe Trolls

Yes you should check if the phases are inverted first. I also had that kind of issue. I exchange + and - wire at the output of the power amp and that solved the problem.

Hope it helps.
Loris

to all cross headers: in case you gonna have more connectors (only missing connectors are good connectors) i strongly recommend to use twisted pairs for the cables.thin.high flex wires. the shorter the better. also adding some weight might help, as the head was made light weight to use on simple , ...