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Tube Testers - whatcha got?

Discussion in 'Amp Tech Center' started by bparnell57, Jun 14, 2016.

  1. Opaltone

    Opaltone Tele-Holic

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    Do you mean you'd like the scale to be 0-100, using the full sweep of the dial, rather than 0-22? Yeah - I wish that was the case with the 707, too.

    - Thom
     
  2. ranjam

    ranjam Tele-Holic

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    The problem is that a 12AX7 is such a low current tube that it is difficult to make that needle move. The meter movement is just not that sensitive. Still great testers. And still better than tying the halves together for a simple emission test. A lot of testers won't even check both halves separately, as with rectifier tubes. Not something that instills confidence.
    If money is no object, and you are serious about testing your tubes;

    http://www.ebay.com/itm/Longhin-Lo4...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
     
  3. jspartz

    jspartz Tele-Meister Silver Supporter

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    Yes, that is the situation.

    Jason
     
  4. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    The emission tester will help weed out defective tubes...and that's it. They will not provide any comparative values.

    Transconductance testers, IF properly calibrated (an expensive proposition and a DIY operation only for those very experienced in electronics) can be useful in comparing quality and matching sides of SOME preamp tubes intended for use in sockets where the plate voltage won't exceed around 180VDC - for preamp sockets in the 200VDC and up range they're pretty useless except for the same use as emission testers - weeding out defective tubes.

    They can't be used to match power tubes, or even know for sure HOW good a specific tube is. Guitar amps generally hit the plates with 320-500VDC; the average Hickok, B&K etc transconductance tester doesn't use nearly the "real world" plate voltage in testing, and as plate voltage goes up tube characteristics change significantly.

    A pair of 6L6's that match perfectly on a calibrated Hickok 6000A may be off by 20-30% in an amp.

    I use a calibrated 6000A - it's used to weed out bad tubes (I have hundreds of tubes and have not checked all of them - I test as I use them). And IF a set of power tubes is fairly close on the tester, I then test them in an amp, using a multimeter AND an Allesandro bias and matching meter.

    If a set is well matched using all 3 tools, I'll mark them as a calibrated set (and I'll test sides of 12AX7's, 12AT7's etc for balance - first on the tester and if they pass THEN in an amp).

    But a tube tester (except for a few very expensive military models and currently-manufactured high-voltage units) of any kind is simply a tool to weed out junk, not a quality comparator.
     
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  5. E5RSY

    E5RSY Doctor of Teleocity

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    PSA: I know I've posted this before, but speaking of having a bunch of tubes lying around, the San Francisco Maritime National Park Association has been in the process of trying to restore the submarine USS Pampanito at Fisherman's Wharf to exact WWII specs for a number of years. They have a wishlist of tubes they are having trouble finding and would love to receive any donations.

    Here's the list: http://www.maritime.org/wish/tubes.htm
     
  6. Wally

    Wally Telefied Ad Free Member

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    I have been wondering how that project is going, E5RSY. I sent them something over 100 tubes back 2 or 3 years ago. I should have kept a list of what I sent them. I just took a quick look at their wish list.....I have some more of what they want. I have 3 of those 'battleship' 5R4's. A fair number of those tubes they want are usable in audio amps, but I have some NOS/NIB 6AK5 and 6AL5. I held them back thinking they were worth something...not much, it seems. I have some of the diodes they need. 6J6's....I have 'em by the hundreds. I have an 80 they need. I guess I'll make up another gift box. I could send them all of the 6L6's they need as long as they would accept UOS that tests good....and were working when pulled...6V6's, too. They can't have my 5851's, though....whoops....that should read 5751.
     
    Last edited: Jun 17, 2016
  7. E5RSY

    E5RSY Doctor of Teleocity

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    I would double-check to make sure they're still working on the project before you sent them any more. I can't tell if that list has been updated in a while or not. Did you get a thank-you or acknowledgement from them for what you already sent in?

    I have a bunch of the tubes they need, but the 9-pin socket on my Hickock quit working for some reason while I was testing them. I need to get it fixed.

    Scott
     
    Last edited: Jun 16, 2016
  8. mitchfit

    mitchfit Tele-Holic

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  9. Wally

    Wally Telefied Ad Free Member

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    Sure did. I talked over the phone with them a time or two. And yes...testing is good for UOS. A lot of what I have is NOS/NIB...they are military purposes tubes from a small stash I came across. Those 6AL5's??? I tried to work a trade with the NOS I have. The tube distributor said Thanks, but no thanks...they have over 250,000 of the..so they said.

    Mitchfit, I hit the wrong key above. Instead of 5851 that should read 5751. Apologies.
     
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  10. FenderLover

    FenderLover Poster Extraordinaire

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    I have a Hickok military TV-7B/U. Still has the military manual in the cover. Never used it.

    I think all you need is a go-no-go tester and the real test is put it in an amplifier. Unless you're selling tubes on-line and you are compelled to list the data as tested on a Brand X tester.
     
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  11. muscmp

    muscmp Tele-Afflicted

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    i have a working knight 600 and an ecco tv7du that needs repairing but it is hard to track down the 83 rectifier tube it needs. i just use the knight to ferret out the supposedly good from the bad.

    play music!
     
  12. Crawfish

    Crawfish Tele-Afflicted

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    I have a Hickok 600A. Don't use it much. As noted earlier, the real test is in an amp or radio.

    You can test filament continuity with a DMM, don't need a tube tester for that.
     
  13. Wally

    Wally Telefied Ad Free Member

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    I have been holding onto an RCA 83 rectifier..in the box... for years just in case a 5F6 comes my way....as if that is going to happen, right? There are 83's on ebay right now....$10-65. There are also some SS replacements plus kits to build the SS replacement. AND...I learned that my Hickok caries an 83 in it. So, I guess I have two of them and may need to have a spare.
     
  14. mitchfit

    mitchfit Tele-Holic

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    Wally,

    PM sent

    mitchfit
     
  15. Hiker

    Hiker Poster Extraordinaire

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    Hickok 600. I'll be parting with it soon, though.
     
  16. bparnell57

    bparnell57 Poster Extraordinaire

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    Update on the Lil' Lafayette tester:

    1 day left on the auction

    Current bid of $17

    My max bid is $35

    I don't have to pay $20 for shipping so my total cost is lower than most people, so I likely will get it as I'm more willing to have a bid of $35 on such a small simple tester.
     
  17. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    ??

    83's are easy to find. They are all over eBay and just about every NOS tube seller stocks them (and almost every transconductance tester uses the 83)3. They're a very common tube. Also, with rectifiers "go-no go" testing is usually all you need - they work or don't.
     
  18. muscmp

    muscmp Tele-Afflicted

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    great info. thanks!!
     
  19. RedRock

    RedRock Tele-Holic

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    I have a grey TV-7D/U with a Dept.of the Army
    manual that I use all of the time. It's a great tester.
     
  20. screamin eagle

    screamin eagle Poster Extraordinaire

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    Tube tester sounds convenient. I've only tested tubes in amps.
     
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