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Tube testing and new testers

phatdave

Member
Messages
351
Where do you guys go to test tubes? used to be able to do it at grocery stores,drug stores,etc. Not anymore.

I called Guitar center and they said they don't test tubes. What do you do? just replace them?

Who makes a new tester that would test modern tubes that we use most often...12ax, el34,el84,6v6 etc?



dave
 

alotawatts

Member
Messages
178
Call TV repair shops.
For what a good tube tester would cost you could by a lifetime supply of NOS tubes
 

Bob V

Member
Messages
1,186
Oh those were the days. Heathkit "hi fi." Riding in dad's Oldsmobile down to RadioShack to test a fistful of tubes that were scavenged from old radios and tv's. I think they figured out that people were testing old tubes with no intention of buying new ones even when they still had them on the shelf.

If your amp's performance is trailing off, it's time for a visit to a tech. Chances are that new tubes will require an adjustment of the bias anyway.
 

Robal

Silver Supporting Member
Messages
1,297
http://www.compu-bias.com/
http://www.vacuumtube.com/toppage31.htm

See this thread: https://www.thegearpage.net/board/index.php?threads/134747
You can find used Hickcock testers on ebay, like a 6000A, but they may or may not be properly calibrated. A basic tester like a Sencore is pretty cheap used, but won't test many parameters.

Really comes down to how picky you want to be about obtaining a variety of measurements that may have not much to do with how good the tube sounds in your particular amp.
 

Tone_Terrific

Silver Supporting Member
Messages
33,344
Where do you guys go to test tubes? used to be able to do it at grocery stores,drug stores,etc. Not anymore.

I called Guitar center and they said they don't test tubes. What do you do? just replace them?

Who makes a new tester that would test modern tubes that we use most often...12ax, el34,el84,6v6 etc?

dave
Out of touch since '78, eh?:D
No matter how a tube tests out, aside from dead, or if you are going for a match, I feel that there is no substitute for trying it in your application to find out if it sounds good, anyway.
OTOH, if you are blessed with a stack of untried tubes a tester would be cool.
 

phatdave

Member
Messages
351
Just wondering what tube amp users do. Just replace tubes?

Even for cheap 12ax7s you will throw 50 bucks a quad. Power tubes even more.

I'm just wondering about the financial potential of owning a tester to test and match tubes.

I am having issues with my 30 watt tube amp. I called G.C and they said Nope we don't test em. So...80 bucks for EL 84 quads and 12ax7s for 66$ on the way.



dave
 

megatonic

Gold Supporting Member
Messages
2,698
I just talked to a friend who bought about 250 old stock and NOS tubes, - Pre '59. He has no way of testing them, and I'd love to score some from him. He also has a friend who has about 1000 of the same and newer.
I'd like to find a tester, too.
 

Husky

Member
Messages
12,090
Where do you guys go to test tubes? used to be able to do it at grocery stores,drug stores,etc. Not anymore.

I called Guitar center and they said they don't test tubes. What do you do? just replace them?

Who makes a new tester that would test modern tubes that we use most often...12ax, el34,el84,6v6 etc?



dave
This is what I use plus a computer based scope
http://www.haglabs.com/vacutrace.html
With this you can do curves on everything including preamp tubes.
I also use this
http://www.maximatcher.com/
It works pretty well for power tubes.

The surplus testers are usually not very useful for testing tubes used in guitar amps. In my opinion they are too hard to trust and dont run at the correct voltages.
 

teleache

Member
Messages
153
Simple tube testers can be found on ebay. Their fine for testing preamp tubes. But can't be totally trusted for power tubes. That can be only tested in the amp their going in. I have dozens of old stock power tubes. 6v6's, 6l6's el34's ect... I don't worry about testing them on a tube tester because tube testers don't have the plate voltage of your amp. Power tube can only be tested for "leaks and shorts" If you put them in your amp. Their checked the right way by warming them up in the "amp", with the transformer plate voltage on them. Using the plug in tester used with your miltimeter Those can be found on ebay too. Mines from SRS. you can find them on ebay. although i'm an anologe freak, i prefer DIGITAL multimeters for matching tubes. I like mine no more the 2 to 3 mA away from eachother. find the tester here :
http://cgi.ebay.com/Bias-Tool-Plate-Voltage-Tester-for-tube-amp-amplifier_W0QQitemZ360139291504QQcmdZViewItemQQptZGuitar_Amp_Accessories?hash=item360139291504&_trksid=p3911.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

6v6's 22-27 mA

el84's 22-27 mA

6l6's 30-35 mA

el34's 35-42 mA
 
Last edited:

megatonic

Gold Supporting Member
Messages
2,698
I own a Compu-Bias. Would there be something I could do with that to test/match tubes?
 

TBIRD Phil

Member
Messages
159
Hmm, never thought about testing tubes before. I just assume to buy new ones. I just re-tubed 2 of my amps with JJ's. I ordered them from http://eurotubes.com and their service was great. I gave them a call and they told me everything I ever wanted to know about tubes, biasing, ect. They have full re-tube kits for a dozen or so brands and different combination of preamp tubes to get that sound you are looking for.
 

megatonic

Gold Supporting Member
Messages
2,698
Hmm, never thought about testing tubes before. I just assume to buy new ones. I just re-tubed 2 of my amps with JJ's. I ordered them from http://eurotubes.com and their service was great. I gave them a call and they told me everything I ever wanted to know about tubes, biasing, ect. They have full re-tube kits for a dozen or so brands and different combination of preamp tubes to get that sound you are looking for.
Yea, Bob and Eurotubes has a good rep, here. But I was talking about how to test & match tubes from a bulk quantity, mostly New old stock and old stock, that potentially have very desireable tonal characteristics.
 




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