Hi, yesterday my new amp Jet City JCA5012C have arrived. When im turning it on it makes strange noise http://vocaroo.com/i/s1mVECwK7oXa. Anyone have solution for this problem?
I have ordered this from thomann so im still able to turn it back.
It makes this noise with unplugged guitar as well as with plugged in. Neverthless I can play normally but this noise is annoying
How loud is it turned up?

Remove and reseat each tube.

Is your mains power properly grounded?
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