Help me diagnose this weird sound coming from my amp

[thrashinbatman]

Grasp the transformer housings (covers), and hit your low E... If the buzzing stops, you'll need to pad the housings. Try attaching a soft credit card size magnet on the offending housing. If the magnet(s) don't quell the buzzing, you may need to coat the interior with some silicon. You can get blue silicon from your local pool store, or Home Depot.

I did this and it worked. I could feel the housings vibrating against one another. I tightened the screws, but I'm not sure it helped much. I also noticed that fuse has blown in the time since I last looked at the back of the amp. Between replacing the fuse and tightening the housings the problem is fixed, at least for now. Gonna keep an eye on those fuses; if one blows again a power tube swap will be in my future.

 

[Goat]

Grasp the transformer housings (covers), and hit your low E... If the buzzing stops, you'll need to pad the housings. Try attaching a soft credit card size magnet on the offending housing. If the magnet(s) don't quell the buzzing, you may need to coat the interior with some silicon. You can get blue silicon from your local pool store, or Home Depot.

I did this and it worked. I could feel the housings vibrating against one another. I tightened the screws, but I'm not sure it helped much. I also noticed that fuse has blown in the time since I last looked at the back of the amp. Between replacing the fuse and tightening the housings the problem is fixed, at least for now. Gonna keep an eye on those fuses; if one blows again a power tube swap will be in my future.

Try the magnet trick... If that doesn't work, coat the interior of the housings with silicon to quell the vibration. Per the clip; it doesn't sound like it's due to volume, which means it could have gaps and/or loose transformer windings. If this is the case, you can either replace the transformer (which is what I would do, given its age), or remove it for re-sealing. If you have been pushing the amp via attenuator, the mains transformer may have failed prematurely.