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FX8 Mark II Tuner, 4 Channel amp switching


New Member

1st question: I just bought an FX8 Mark II. I have updated to the latest firmware and deleted all the presets. I have been trying to figure out how to use the tuner. but can't seem to. I step on and hold the f3 switch and the tuner shows in the window but will not move while plucking strings. It seems as if the tuner is not receiving a signal. Can anybody help shed some light on how the tuner works and what I am doing wrong?

2nd question: I have a Mesa Boogie Road King II with four channels but the FX8 only has two relays. Is it possible to switch all four channels with the FX8? If so, how?

Thank you for your responses!


Page right while looking at the tuner and see if there are any options for input select, like pre vs post, and make sure you’ve selected the one your guitar is physically plugged into.

I believe each relay jack supports 2 signals, so a y cable TRS to TS may work. (I haven’t used the FX8 in a while, maybe the Owners manual details this.)


Definitely check the input source for the tuner. That is likely your problem.

If the TRS to TS cable setup doesn't work out for your amp you should check out a VooDoo Lab Control Switcher.


New Member
Awesome Chris!! Thank you for your response. Yours as well OrganicZed. Everything is now working perfectly.

Thank you again!!!😀
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