Quote:
Originally Posted by FreddieFerric
Now that I'm getting back into tubes I may need to pick up one each of these testers, but here's my question...
Can this power tube tester find the bad tube in a quad set of TungSol 6550's. Only one is bad, but which one?
I removed all of them and replaced with a quad set of Svetlana 6550's which I find sound a tad bit more lean and cool than the TungSol's did.
Any ideas on this?
For the record, I never really got out of tubes, it's just that I don't currently have any tube gear in my main listening room. That will soon change when the MC 1502 arrives.
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Yep - that's one of the primary purposes for a tube tester.
That said, how do you know one is bad from a set, but not specifically which one? Were they all in an amp when the main fuse blew?
Some amps have per-tube fuses. Some amps have per-tube status indicators. Sometimes a bad tube will go cherry red plate before totally failing (and possibly blowing a fuse). Once had a EH KT90 "catastrophically" fail: a mini fireworks show on that one tube followed by a pillar of smoke (that being the resistor it carbonized) and THEN a blown main fuse (lol).
I've also seen the scary quick "flash" on a new KT120 that continued on working just fine. Apparently caused by a small impurity or bit of debris that can burn off randomly during operation. The getter should absorb any off-gassing from this. Bigger flashes could be a temporary short that can pop a fuse or trip any "sentry guard" circuitry. Such a tube "might" be ok when re-tested or run again.
But over 15+ years of audio tube usage now, I'd say the incidents have been quite rare. For the most part tubes & quality tube gear is extremely reliable. Still a good idea to have both of these testers (I have the maxi preamp but not the maxi matcher tester - yet).