Rotel RA 985BX little hum on speakers when the volume is set to minimum

[HMrules]

I have a Rotel RA 985BX that I bought almost a year ago, then I took it to a hi-fi repairer who did a refresh, more precisely the replacement of worn parts, the amplifier works better after that, sounds fuller, more open, etc. In general, the amplifier sounds great, but I hear a little hum on the speakers when the volume is set to minimum, the same as before the refresh, I thought the hum would disappear after the refresh, then I took the amplifier to another repairer who examined it in detail and said that the amplifier is correct and fine and that he would not touch anything else on that amplifier, about the hum he told me that it is heard because the preamplifier is close to the transformer and that is why the preamplifier picks up interference from the transformer and that is why the hum is heard, otherwise when I removed the bridges at the back and tried to listen to the Rotel directly on the Main In without the preamplifier, no hum is heard.
I like the sound of the Rotel which is excellent, precise, analytical, detailed etc. but the hum bothers me, that's why I'm thinking of selling the Rotel and buying the Harman/Kardon HK 6650R, do you think switching to the HK 6650R would be a good choice?

Otherwise I use JBL ES 90 speakers.