So this morning I switched on my trusty Allnic and Tuner and all was well as I listened to radio 4 through breakfast. I then started to tidy up and went into the lounge and realised things did not sound quite right, in fact I was missing the left channel completely. On inspection of the amp I immediately could see that there was no current on the left channel current gauge. So I dug out my spare 300B's and swapped over, powered up the amp and hey presto left channel reception was resumed.

So obviously the 300B valve has failed. I am a bit surprised and concerned about this. The valves are Psvanne 300B Black Bottles purchased new about 3 years ago. Originally I used them in my mono-blocks for about 18 months and I would estimate they did about 800 hours and then in the Allnic doing about another 700 hours. 1500 hours does not seem a great deal to me for a 300B, or maybe I have the wrong view.

I'd appreciate others views or experience on this.

Thanks

Adrian