Tube Tester?

[cstmar01]

Any of you guys who are tube heads use a tube tester on a regular basis? Seeing my VTL's do not have an auto bias feature or sensor to know when a tube goes I was thinking of picking up a tester.

Not sure if I should do something new or look to the old school testers. Differences? If new who should I look into, if old?

Thanks for any help!

[vintage_tube]

KT88s/6550's correct-o?

Maximatcher...$599 from Seattle -- Current State-of-the-Art Tester made in USA.

Receives the VT seal of approval (ask Dan -- he's seen it & may have used it a few years back).:thu mbsup:

There is topic on this in the archives -- do a search.

Bob

[jdandy]

cstmar01.......If you are going to use a tube preamplifier and/or a tube power amplifier, an accurate and reliable tube tester is a nice tool to own. The Maximatcher tube tester Bob (vintage tube) has makes short work of checking power tubes, although it doesn't check small tubes. Bob also has a vintage Heathkit TT-1 tube tester that is in perfect condition. It tests all the tubes an audio enthusiast will likely use. The Heathkit TT-1 is a jewel, and very hard to come by in good to excellent condition.

Trying to locate and purchase an older tube tester is a hit or miss operation. Most older tube testers are worn out from years of hard service back in the days of tube based televisions and radios. Many are sold on ebay, and represented as being in good condition, but are often in poor condition, or do not work at all. I learned the hard way when I purchased a Hickok model 800 tube tester from an ebay seller. It looked great, was represented as his father's old tube tester in good working order. It was not in good working order. I sent it to a technical shop to get it repaired and calibrated, and wound up just giving it to the tech boys for spare parts. It was beyond hope. I got stuck for several hundred dollars. I wouldn't make the same mistake again. Try to find a new tube tester if you can.

[cstmar01]

Dan and Bob thanks for the information!

I was looking at the Maxi at one point but have never heard of anyone using it.

I'm sorry I forgot to check the older posts but it just was something that popped into my head last night as I was listening.

I would like to avoid having a tube go while I'm listening. I've had some harmonics on one of my tubes when I have no music playing there is a high pitched noise that I can hear but sometimes it will go away after a few minutes after warm up. I can never tell what tube it is but figure it might be on its way out.

And currently I'm running 6550 but might try out some KT88's this fall when I get more time to listen.

[vintage_tube]

MaxiMatcher is the ticket -- can test a quad at a time (even though the manufacturer suggests to increase life of the machine and transformer, only test a quad or two at a time and let it rest. 24 hour a day quad testing will probably result in overheating and a broken machine).

Having said that, I have tested 4 quads at a time (one after the other) and then unplugged it -- it doesn't get hot -- just my way of doing it. After 15-20 mins, plug it back in and test another 4 quads.

Best SOTA tester for the price & as Dan so notely noted -- is not capable of testing 12v tubes.

Bob

[dmnc02]

I second the suggestion to look into a new tube tester. However, I would suggest that you look at the Amplitrex AT1000, which allows you to test pretty much any audio tube (including small signal ones) and to test power tubes at higher voltages than the MaxiMatcher. The only downside (as often is the case) is the significantly higher price. There is also normally a waiting list.

[Whart]

There are also a couple of good resources on the web about the basic differences, including an Idiot's Guide and an article in AllTubeTesters on 'Which tester should I buy?"
Someone recently gave me an immaculate BK 777 which I have not calibrated. I gather than while it is easy to use (and it came with everthing, including the book of tubes matching socket numbers, otherwise the thing would be about useless), it doesn't test mutual conductance, but only emissions, on small triode tubes and that this apparently means it is not really accurate. I haven't had time to calibrate it yet, but was going to, just to play around. It doesn't have the frankenstein lab look of some of those Hickoks, but a more early seventies plastic suitcase appearance.
I think a vintage oscilliscope would be a fun companion for the workbench.
I wonder about those commercial ones that used to be everywhere- in RatShack, at Lafayette Radio, and in hardware stores. Any of those any good? They gotta be collectable in their own right.....

[jdandy]

Originally Posted by dmnc02

I second the suggestion to look into a new tube tester. However, I would suggest that you look at the Amplitrex AT1000, which allows you to test pretty much any audio tube (including small signal ones) and to test power tubes at higher voltages than the MaxiMatcher. The only downside (as often is the case) is the significantly higher price. There is also normally a waiting list.

dmnc02.......The Amplitrex AT1000 is a bit pricy at $2675.00

[dmnc02]

I did mention that price was a downside. If anybody is interested, here are a couple of YouTube videos that show it in use.

[ame=http://www.youtube.com/watch?v=fAFr-BcxUgQ]12AX7_fixedbias - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=WY1pCr62QDY]6L6_autobias - YouTube[/ame]

[vintage_tube]

IMO, you will need a tester for a 6550 tube moreso than one for a smaller voltage tube.

The decision is not necessarilly the price of the Amplitrex AT1000; what yo should also consider how often would you use it? If quite often & for the large & small tubes, then that practice may 'trump' the Maximatcher.

On the other hand, if seldom & you'd only use it primarilly for the 6550'sl then the Maximatcher is, as I mentioned earlier, the ticket.

I'm not knocking the Amplitrex AT1000; I've seen it & used it. Fabulous machine, but as Dan states, it's price is 4 digits long.

Bob