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If buying a tester would save your amp or pre then it's money well spent.
I have a Sencore Mighty Mite tester that's good for general testing including shorts. No gm though. For a true test of gm you'd have to buy an Amplitrex. The Sencores can be had on ebay for not a lot of dough. I think I got mine for $75. I also see testers on craigslist all the time. If buying a tester would save your amp or pre then it's money well spent.
True, but with that way of thinking, you'd have to have a tester for every piece of equipment you want to put in the chain.What if a brand new driver is shorted internally and you blow your amp. Should you now be expected to own the equipment, and be required to test the specs of a driver?How many here have ohm tested their drivers before they wired them up?Nah...I'm not buying it. WHen you sell something, it is with the understanding that it works to it's rated specifications.If it doesn't then you're selling paper weights and need to advertise them as nothing more, and charge accordingly. But then again, I've come to expect to receive things I've bought as they've been sold to me.Bob
NOS/UOS tubes are a special circumstance. I would imagine Steve got them from ebay and not a reputable tube dealer; what reputable dealer wouldn't test them and notice the short? These tubes are old and have likely been sitting in a basement for decades, and then they are shipped perhaps a couple of times before arriving on your doorstep. I wouldn't trust them in my amp until I had tested them, for the exact reason Steve described. Hell, I wouldn't trust any electronic device made in the 50's or 60's before completely checked over. New equipment and speakers? I'd just plug that stuff in. 1960's speaker? I'd probably plug it in to a cheap receiver first. Even if the tubes were tested prior to the sale who knows how rough shipping was on them and what could have loosened up in transit. I have found a few shorted tubes in my collection since buying the tester. I think it was money well spent.And you're not even completely safe with new production tubes. I bought a quad of Black Treasure KT88s a couple of years ago that were shipped from China. They were brand new and factory tested/matched. I still tested all four upon arrival and one of them had an intermittent short. I can only imagine the damage that tube could have caused if I hadn't tested it beforehand.FRM, the Amplitrex is the only tested I know of currently in production. It's great but it's pricey. Bruce Rozenblit of Transcendent Sound had a kit for a while, and I heard he was designing a new and improved version to be released soon, but it's still $700 or $800. As I said before, there are always lots of them on ebay. Some may need calibrating by a professional but even then you could still have one for under $500 total. And for the DMM, you could test for shorts with it but keep in mind that you're testing a cold tube and heat expansion could reveal a short that otherwise tested fine cold. Tube testers test for shorts with the tube hot.
Yea...ok. I guess you sold me on the idea. You made some good points there Ericus.I'm still worried about where the smoke came from. That's not good.Bob
Hey! This is one of the thing tube user fear every time putting in new tubes. Because of that a few years back I decided to pick up a Hickok 6000 tester. I test all tubes new and NOS before I put them in my system. Unfortunately there are two tube types in my system that I can't test on this tester... 845 and KR Audio 842VHD, don't know setting for that later one. Anyway, not everyone have tube tester or want one... so keep your finger crossed. Take care,Buddy
Yeah, I guess I'll have to pop the bottom and have a look see.The silver cap on that tube went blue and gold in spots.