Buzzy Bass head

[Mook]

[color=#282828][font=helvetica, arial, sans-serif]Hey all.... My MB fusion head has started making a weird buzzing sound. I thought it was a tweeter blown first but tried different cabs, leads, basses and the same with all of them... Used a different head and no weird buzzing noise. I'm guessing it's something electrical but thought I'd see if anyone's come across the same thing....I did a short YouTube clip... Hope you can hear what I'm talking about.[/font][/color]

[color=#282828][font=helvetica, arial, sans-serif]It has the three valve pre-amp so figuring (hoping) that it's just a valve that needs replacing. [/font][/color]

[url="https://www.youtube.com/watch?v=w_0IL0SZZpY"]https://www.youtube....h?v=w_0IL0SZZpY[/url]