Can someone tell me what wrong


Hi there
i need some held with speaker hissing noise
i recently noticed some noise come from my right speaker 
the speaker is venture audio grand mk3 and driven by vta m125 tube mono block, it’s kind of loud, i can hear it from 4 feet away the speaker with the preamp turn off, it doesn’t effect by the preamp volume 
so here is what i did
Remove the preamp - still the same noise
swap the mono block - still the same noise
swap the speaker cable between left and right - still the same noise
hook up a vintage dynaco st70 - no more noise
hook up the right channel mono block to the left speaker - no noise 
so what could be wrong here?
I didn’t have that noise before 
This thing really drive me nut
Thank in advance 
 

128x128ownut
+1 oldhvymec
My guess is noisy valve only because he said he just noticed it...
@dill I did using a different speaker cable, but still have same problem 
@twoleftears i did swap left mono to right mono speaker , but the noise didn’t move, noise only come out from right channel, im using audioquest rocket88 speaker cable
@oldhvymec
1 i will try to swap the tube later today 
2 the 2 mono block plug on the separate wall plug before they make noise, i then plug them to the same power strip, still have the noise at right channel 
3 the ic connection is good, it still make noise when I remove all the ic
4 ground loop should not be the problem, if i plug only 1 amp it still make same noise 

thank for the suggestion 

If you have swopped over each single component in turn and kept every other variable the same, and the noise never follows to the other channel one particular component, but sometimes goes away in both channels after you've made the change, then it is intermittent and, as already suggested, probably affected (temporarily cured) by the simple act of swopping something over.