#16
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I wish I had one that does it all, but I will end with saying don't get a simple emissions tester if you are serious about what you are doing.
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"Face piles of trials with smiles, for it riles them to believe that you perceive the web they weave, and keep on thinking free" |
#17
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The hickocks are nice, but expensive. mutual conductance is nice, but not essential, if youre mainly trying to find shorts and determine if tubes are tired or still have good life left. The Eico testers are better then the cheap emissions testers, and generally affordable, and will get you by until you can score a deal on a better one. I used a model 667 for years before i found a Hickock 600 in an antique store for 40. And another (model 6000)i got from a coworkers uncles estate. another one I like is the Jackson 658, but they seem uncommon. I found one at a surplus dealer for $10. Other overlooked units are the better heathkits, which are true mutual conductance. An emissions tester wont catch all tube issues, but the money you save could be used for a stock of known good tubes to test by substitution, which is more reliable than any tube tester anyway.
Last edited by Olorin67; 12-31-2014 at 12:42 AM. Reason: Spelling |
#18
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You can add a zero to the value of your TV-7 if it's in very good working condition |
#19
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I am also a lot more adept at using the TV-7 than the 667, I have had it longer and I find the pointer knobs and its physical layout a lot more appealing and better designed for testing lots of different tubes in a row. The 667 has the edge in heater cathode leakage though and I like its great big meter. The roll chart in the 667 is a bunch of nonsense, I have a printed copy I use instead of wheeling back and forth. Oh and another word about EICO, mine was originally a kit and the original builder made some wiring errors. I had to troubleshoot it when I got it because certain aspects didn't work properly (the transistor tester). The TV-7 on the other hand came with a bunch of military calibration stickers on it and built like a tank. |
#20
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The military testers used to be cheap and plentiful.. Wish i had grabbed one back when they were plentiful!
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Audiokarma |
#21
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antique electronic supply used to have them for cheap, if I had known they would go up in value so much... oh well I guess I could say that about many things they used to sell cheap!
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#22
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Perhaps more appropriate for another entire thread, but a discussion on transconductance and the measure of mhos (yes ohms spelled backwards) would be well worth the read for many. It is often disregarded or misunderstood, but in fact is very important in tube performance evaluation. The formula is G (mhos)= plate current/grid voltage.
It breaks down to the ease of electrons to move within a tube and I would call that pretty darned noteworthy. So for this thread about testers I would certainly grab a unit with that capability if I could. Any thoughts?
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"Face piles of trials with smiles, for it riles them to believe that you perceive the web they weave, and keep on thinking free" |
#23
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The same time the unit of frequency CPS became Hz, MHOs became Siemens......I happen to like the old names better.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#24
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Always preferred the UK method of noting transconductance, mA/V. Milliamps of plate current change per volt of shift in grid potential. Much more intuitive...
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#25
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Some old testers (1930s) tested tubes that way. A small battery was used to apply a steady voltage to the grid, then you would compare plate current on the meter as the battery was switched on and off. It was called the 'grid shift' method. Basically it gave you two points on The operating curve. A tube with a worn out cathode would produce less shift in current, and ones with grid issues such as shorts would also not show a normal grid shift.
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Audiokarma |
#26
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I like my Hickok 6000A tester. It will test all the common tubes, as well as diodes and transistors. It will test dynamic mutual conductance, shorts, gas, continuity... The whole bit.
I was lucky and got mine for free. I was working in the engineering department back in college and they needed help emptying out the chemistry building stockroom in preparation for remodeling. As we were hauling items out to the big dumpster, I saw a small red suitcase-like box with an electrical tag on it sitting next to it. I opened it up and it was a tube tester! I asked if it was to be thrown away, and was told it was- if I wanted it I could have it. After replacing a few paper capacitors and locating owner's manuals, it has served me well. |
#27
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They can be found in unlikely places... Found my Hickock 600 in an antique store for $40, case was a bit beat up, it was next to a cheap emissions tester that looked nicer but was priced at $125... I have a 6000a, bought from a co-worker who was cleaning out an estate. he asked me about it since he heard i was into tube stuff. I offered him $50 untested and we were both happy with the deal.
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#28
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I bought my Hickok 580 (their first all solid state tester on par with the 539) 2nd owner at a ham fest in 1987 for $50; it was and still is in mint physical condition. It now needs some minor repairs like the early generation silicon diodes falling apart and a re-cap. Talk about a return on investment 25 years later; they are going for $500-$1,500 on that "auction" site now, top dollar being in the Asian countries. I should probably think about selling it since I'm not really into (or have the itch for) tube stuff anymore.
Tom (PK) |
#29
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I have several "better" testers, but my go-to for shorts & emission is an Accurate 257. Easy to use, tests most tubes and even some older CRTs and won't break the bank to purchase.
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AUdubon5425 Youtube Channel |
#30
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I have one of those too, and my sentiments agree with yours on being quick and easy to just do a go or no-go check on a tube.
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Audiokarma |
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