Autobiasing tube amp failure


The smell of electronic burning alerted my wife and I. I turned the amp off and removed the power chord. I opened the casing and couldn’t see anything wrong. But there was definitely a strong burnt electronic smell. Later investigation showed that one of tubes had gone way out of bias and caused one of the resistors to be overloaded. 

My question is how can this be prevented in future? Autobias means no way of reviewing the tube settings and performance.

The tubes and amp are less than 150 hours into their life. 
128x128johnread57

Showing 1 response by ebm

This happens with tube amps i had CJ Premier 5,ARC D150 etc i now use a solid state amp as i hated always getting them fixed.Consider yourself lucky as a few times they blew out my Tweeters.