It is debated by Audiophiles, but any electrician or electronics tech (hi ya !) with a few year's of experience will tell you that open grounds take you back to the safety standards of the 40's. (not a good thing)
The JoLida has tube high voltage under it's hood. Be VERY careful.
Grounded plugs are legal necessities and insurance requirements in most communities.
Bypassing them may be lethal and could void your homeowner's fire and liability coverage.
If the gear has an inherent wiring flaw, lifting ground may mask it, but the device is still defective.
What to do ?
Test the amp at another location or two to verify that it isn't defective, before the warrantees slip away.
If the amp is good:
Try a different power strip, in case it has the fault. (You'd be surprised how may bad power strips there are, especially the "surge protector" type)
Use a VOM get someone who is good with one (some electricians...) to verify that you have good wiring to your wall socket.
Search up "NEMA" for basic information.
Be very careful with ground-lifted gear.
The chassis may have a lethal voltage to ground, plumbing and heating systems, or other equipment.
FWIW, my opinions...don't run ground-lifted gear and and do not substitute a water pipe for a proper circuit ground.
lastly, test or have your household wiring checked.
+T for grief with new toys. It takes some of the fun out.
But you will get this figured out.
Break down the problem and eliminate a piece at a time until you find the culprit.
I had a very similar experience in a house where some fool buried a wall socket box that had leaky old cloth wiring behind some sheetrock. I shut down circuit breakers until the bad circuit was found.
I then had an electrician run down the bad wire.
I ended up buying a power conditioner during the troubleshooting time, just to keep my sanity.
The conditioner isolated the gear from the circuit, yet allowed me to keep a circuit ground.
Good luck ! Be careful.