|
6BD5 followup
I decided to try to understand why a 6BD5 that tested so good, performed so poorly. I guess if something seems to good to be true, it is.
The tube is definately NOS. The getter looks good at first glance, nice and shiny, but looks horrible when you shine light through it. I also noticed a slight haze on the envelope around the plate area.
So, I put it back on the tube tester and turned out the lights. When I did the dynamic test there was a blue glowing haze between the plate and cathode. The tube is gassy. It acts like it has higher emission, but is really gassy.
The supplier only gives a 10 day warranty period and I tend to be too trusting. I'm dissappointed that I had two bad tubes in one order. I've had better luck with eBay. I'll still use them but I'll test as soon as I receive any tubes and I have a better idea of what to look for now. Hopefully I won't fool myself like I did with the gassy tube.
I have a Senecore LC3 leakage tester which works great for the tubes it handles, but it doesn't do the 6BD5 or 6Y6. The Precision 10-12 will find shorts, but doesn't do a sensitive leak test. But I have seen 1B3's glow blue from gas with it and now the 6BD5.
I'm tempted to try a 6AU6, would that make a good substitute for a 6BD5?
John
|