2. amps-preamps
  3. 1356837276

Help me diagnose the problem

I've got a Rogue Tempest II Magnum. A couple weeks ago I heard a 'pop' and then noticed that the left channel wasn't quite right. Further probing led me to the KT90 in the V1 position- it was not hot to the touch. Mark at Rogue suggested I check the fuse to V1. Sure enough, fuse blew. Tip off was the tube could not be biased. Put in a new fuse, and we're good.

Today- I heard something not quite right from the left channel again. Popped the lid, saw I could not bias V1. Pulled the fuse and it was blown.

2nd V1 fuse blow in as many weeks.

Why am I blowing the V1 fuse? FWIW, the amp is nearly 4 years old. Could a tube issue be causing the V1 fuse to blow?

Thanks!
128x128zavato

Showing 1 response by justlisten

justlisten's avatar
justlisten
489 posts
 
In case this may help. I just resolved a somewhat similar problem today with one of my AirTight ATM3 monoblocks.

Earlier this week, the right amp popped, and I gradually lost volume. I shut down the amp and as the amp has built in bias meters, powered back up looking for any issues with the output tubes. All seemed ok, but I was getting no bias readings at all.

Tested the power and input tubes and discovered a 12ax7 tube was weak. I alsoI tested both fuses and noted one showed slightly open but still "good"

I replaced that fuse with a new one and am back up and running.
More to discover