Tube Amps / Music Electronics
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|4/25/1999 12:16 PM|
||Buying a used tube tester|
Pardon me if i've posted this twice, but I have an opportunity to pick up a tube tester, reconditioned by a reputable tech, fir $40 to$50. Is this a sure buy, or just an average price.?
|4/25/1999 4:31 PM|
|John M||Good news Bad news|
Good news is nice price if somebody put the work into reconditioning it the work alone would be worth that. Bad news is 99% of testers don't really give you any real information (besides the tube being shorted)about the condition of the tube. Because they don't run the tube at real working voltages they are actually of little use. Incidently the real purpose of these testers was a scam to sell replacement tubes.Radio-TV Experimenter 1952 article claims repairman simply swaped out old tubes for new to test TVs for problems rather than using tube testers. So you might want to pick one up to test for tubes that are totaly nonfunctional (you wouldn't want to use your amp for this)but don't expect the tester to give you any kind of acurate info about the tubes beyond this.
|4/25/1999 7:21 PM|
Hello, John. Are the testers you're referring to the ones you used to find in drug stores and places like that, or the HickokB+K, etc. test equipment type, or both? I can understand how the dime store type testers could be a scam, but I find my Hickok very useful in rough gain matching and finding leakyweak tubes.
|4/30/1999 9:31 PM|
The drug store tube testers were really *less* critical than the good ones like Hickoks and B+K's.I know this 'cause I've owned a few, and I also bought a lot of stuff from the U-Test-M
company after they went belly up,including
one of their tube testers.The ones I saw were
just basic emmissions testers, nothing fancy.
I can't imagine places like B&K and Hickok making testers that intentionally rejected good tubes (altho I suppose they could've been modified by the unscrupulous), these folks were test equipment manufacturers who sold gear to real test labs, where this kind of behaviour would've been and is totally unacceptable.
As far as TV techs "recycling" tubes for some extra cash, now *that* I believe. I've seen enough tube caddies full of used TV tubes...sometimes carefully sorted right back into boxes with the same brand names, no less ..for me not to believe this. Generally, the tube caddies that are most likely to have good tubes are ones from guys who were doing comm gear and test gear maintainence, it wasn't a good idea to put "recycled" tubes in stuff like EEG's and state police radios!
|4/29/1999 11:31 AM|
||Re: Buying a used tube tester|
What make and model? If you watch the newsgroups and auction sites, you may be able to pick up a TV7 type for about the same, or a little bit more.
|4/29/1999 5:52 PM|
I built a tube tester that measures cathode current and works at 'real' plate voltages. you can also audiably check for microphics and
noises. its in the 'TUBE AMP TALK' book, by Gerald Weber.
|4/29/1999 6:22 PM|
If you're adventurous at all, and you want something to be proud of, check out Steve Bench's web site for the schems for a very nice tube tester. It's good for plate current and transconductance, and can probably be adapted to trannies on hand.
There's tons of other useful shit on his page too. If you don't have it bookmarked, do it now:
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