Marshall Tube Amp Problem/Please Help

[GoPoStAl]

I have a 1989 reissue of the 1988 Jubilee series Marshall 2554 valve amp. It seems to work fine on the clean channel but if the overdrive channel is used and the power tubes are driven (volume above 7ish), an intense buzzing sound is emitted from the amp. I cannot even tell if the guitar is playing due to this. Any help/suggestions would be greatly appreciated

[Valvehead]

try different power tubes first

[GoPoStAl]

sorry i forgot to mention that i have recently replaced the power tubes

[DrNo]

Put the old ones back in and report.

[Enzo]

Exactly. Did it used to do this with the old tubes? If not, then all the more erason to suspect the new ones.