Hasnt been my week with audio this week. Having had problems with my active speaker recapping I thought things couldnt get much worse. Alas, my Audio Note Oto SE is now playing up.
Upon turning it on, with volume set to zero, there was a loud humming(that grew in volume as the amp warmed up) coming from the speaker/s(didnt leave the amp on long enough to check whether it was one or both channels).
I took the lid off to see if there was anything obvious but there wasnt - pushed all the valves down to make sure they were seated properly. Tried again but same result. I then tried with just one speaker connect and this time the amp started to make a noise like an old police siren. obviously i turned it off sharpish.
The good news is that my speakers are fine and my trusty ol Pioneer A400GTE is providing me with some music.
So any ideas about whats causing it? My thought was maybe a dead valve or two in one of the channels - though not sure how to test that -can i just swap them into one channel and leave the other channel without valves or is that a big nono?
Any advice gratefully received