I've recently bought a new Blackstar HT - 50 club with 2x 12 cabinet and today I've realised that it makes strange buzzing sound in a clean channel( volume around middle) while I play low E string on 3rd and 15 frets. At first I thought it might be problem with my guitar , but I didint hear buzzing sound after I swiched my amp to small 10 w Roland practise amp. I've tried to reconnect all the cables , I've tried to use another cables as well , but nothing solved the problem. Maybe the problem is grounding or smth else? It's my firs tube amp so Im new to its problems. Thx for help
With any tube combo, if you turn it up loud enough, you'll get tubes vibrating, which can cause a microphonic type of noise. Since you're noticing this on two similar notes (G), perhaps your cab has a resonance?
Can you describe the sound further?