Thanks all.
I have basically the same conclusion. I am thinking that the tube failed (arced), and the smoke was from a fried resistor.
Rather than put in another tube, thinking that having the amp checked out by a tech is the best corse of action.
Air Tight 300B Flame Out
I was listening to my Air Tight 300B amplifier (fed by a Lamm LL2.1 Deluxe preamp and driving Charney Maestro speakers) starting making popping noises through the speakers. By the time I got to the amp to look, the right channel 300B tube was lit up brightly and smoking. Obviously, I turned the amp off right away.
The 300B tubes are the new issue from Western Electric with maybe 100 hours on them.
Any ideas on what may have happened, next steps, and anyone that can service Air Tight on the west coast? The Lamm preamp is a recent addition. Wondering if the preamp somehow caused the problem?
-GAR
Showing 2 responses by gareents
@carlsbad2 @sns @testpilot Thank you for your responses. The little smoke, but strong smell, was only from beneath the 300B tube that went bad. Probably an indication of fried resistor? No discoloration on the tube socket or on the tube pins. The tube did not show any sparks, nor a red plate. Rather, inside the tube was a roiling aurora borealis of beautiful blue and green plasma throughout the entire tube. Series of crackles and pops and a final louder pop through the speakers, no noise from the amp itself. The AirTight ATM-300 uses auto bias. I purchased the WE tubes from Uncle Kevin at Upscale Audio. Assuming they are authentic..... @carlsbad2 Thanks for the offer of cheap 300B tubes, but I have some other 300B tubes myself. However, given the smoke and burning smell, I am reluctant to put in another tube. Think I will just bite the bullet and have the amp looked at by a good audio technician. Turns out we have one here in the Sacramento area. Thanks again to you all. -GAR
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