Tube Testers

[CKKeung]

I visited Ricky, a "tube-guy" friend who had an Amplitrex AT1000 tester last night.

The AT1000 is nicely built and sturdy.




It has an usb socket to connect with a computer for control and printing of graphs or tube measurement labels.



Although he is a tube buyer but not a seller, the AT1000 is very useful for him.
Here are just two of the many examples :

1. As Albert had mentioned on #9, the AT1000 is very sensitive in detecting tubes with occult problems. Ricky bought some NOS KT77 from overseas sellers and found that some of them were defective and could not be detected by the sellers' or local tube shops' tube testers.

2. He recently bought two Kondo Melius poweramps (for bi-ampimg) which contains 4 EL34 tubes. Even though the tubes had been matched inhouse by Kondo, re-measurement by AT1000 can reallocate/match the eight EL34 in a better configuration.

 

[dminches]

Simple Emissions vs Dynamic gain

Can some explain the difference between these types of testers? Also, is dynamic gain the same as mutual conductance?

I recently purchased a pair of DX-235 tubes. When I tested them in my Jackson 646 (emissions) they were not well matched. In my DAC there was a significant difference in the left and right channel output. The seller used a Hickok TV-7 and said the dynamic gain was close. Why is there a discrepancy based on the type of test?

 

[Zero000]

Two panel Avo bought for £25, restored and modified to test 211 tubes - well, at least provide a meaningful reading

I use it a lot, mainly to test triodes.

 

[Barry]

Simple Emissions vs Dynamic gain

Can some explain the difference between these types of testers? Also, is dynamic gain the same as mutual conductance?

You can't use an emissions tester to match tubes. There are also a few reasons why a mutual conductance tester may not be very good at it either including calibration issues, accuracy, and test voltage limitations to name a few.

To understand the difference between an emissions, dynamic, and mutual conductance tester go here:

https://www.radiolaguy.com/info/Mutual-Emission.htm

 

[Lowrider75]

You can't use an emissions tester to match tubes. There are also a few reasons why a mutual conductance tester may not be very good at it either including calibration issues, accuracy, and test voltage limitations to name a few.

To understand the difference between an emissions, dynamic, and mutual conductance tester go here:

https://www.radiolaguy.com/info/Mutual-Emission.htm

Are there any modern tube testers which accept 6SN7? They all test octal power tubes.

 

[Gjo]

Triplett 3444 rebuilt and calibrated by CG Industries. Also, modified with digital meter to measure tubes with plate current above 50ma. A stock 3444 can not test these tubes.

 

[Lowrider75]

Triplett 3444 rebuilt and calibrated by CG Industries. Also, modified with digital meter to measure tubes with plate current above 50ma. A stock 3444 can not test these tubes.

I wish there was a non-vintage unit to test Gm on my tube collection for personal use.
What do guitar players use?

 

[godofwealth]

I use the Amplitrex AT1000 as well. Great product. The designer Chris is local here in California and very responsive to my emails. One of the best investments to make if you like tube gear. It’s highly customizable and if you hook it up to a PC, it can serve as a tube tracer as well.

 

[Jim Hagerman]

I used to make one called the VacuTrace. Works in conjunction with an XY oscilloscope, so it operated a lot like a Tek 570. Matching tubes was easy as it plotted (in real time) overlaid curves. If you can find one on the used market, scoop it up!

 

[vintage_tube]

I actually have 4 tube testers (well maybe 3 now).
The 1st being one I and a fellow Army buddy made from a Heathkit kit purchased in downtown Manhattan in 1972. It's a TT-1A and in immaculate shape & condition. Have every manual, every part/instruction to build manual, etc. The only thing it's missing are the boxes from Heathkit.
The 2d is a Maximatcher Power tube tester (actually sold it last week & shipping out this week).
The 3d is a Maximatcher preamp tube tester.
The 4th is a new addition from a Canadian Company - Space Tech Labs ATT-3.02. I received it from Space Tech Labs a week prior to picking up the VAC mono amps/preamp & having not used it in that week (still boxed up) I took it with me when I drove down to Sarasota. I showed it to Kevin and not being aware of that company nor tester, showed interest in running it thru its paces. So, long story short, he's had it a month and am to call him back this week and get his take on it and send it back (to me). I'm hoping he liked it and can take the place of the two Maximatchers. Will see.

Bob

 

[Gjo]

I actually have 4 tube testers (well maybe 3 now).
The 1st being one I and a fellow Army buddy made from a Heathkit kit purchased in downtown Manhattan in 1972. It's a TT-1A and in immaculate shape & condition. Have every manual, every part/instruction to build manual, etc. The only thing it's missing are the boxes from Heathkit.
The 2d is a Maximatcher Power tube tester (actually sold it last week & shipping out this week).
The 3d is a Maximatcher preamp tube tester.
The 4th is a new addition from a Canadian Company - Space Tech Labs ATT-3.02. I received it from Space Tech Labs a week prior to picking up the VAC mono amps/preamp & having not used it in that week (still boxed up) I took it with me when I drove down to Sarasota. I showed it to Kevin and not being aware of that company nor tester, showed interest in running it thru its paces. So, long story short, he's had it a month and am to call him back this week and get his take on it and send it back (to me). I'm hoping he liked it and can take the place of the two Maximatchers. Will see.

Bob

That Space Tech Labs ATT-3.02 looks very interesting! Moreso with the optional 845 expansion module that enables testing of 300b, 2A3, 845, 211 and rectifiers.

 

[vintage_tube]

That Space Tech Labs ATT-3.02 looks very interesting! Moreso with the optional 845 expansion module that enables testing of 300b, 2A3, 845, 211 and rectifiers.

Yes, it does even though initially I ordered it without the optional module. As my amps and pre were being built at VAC in Sarasota, I mentioned the
the unit to Kevin, who wasn't aware of Space Tech Labs. He expressed an interest in trying one out & it just so happened to arrive a few days before the trip to Sarasota so brought it along still boxed up. I spoke with him yesterday and he'll try and set aside a few hours to run it thru its paces and give me his take on it and send it back.

I can't think of a better person to get an opinion from on the ATT 3.02 than Kevin. Especially since he has multiple legacy and modern testers to compare it with.

I'll start a new post on the ATT 3.02 once I hear back from Kevin and try it out for myself as well.

Bob

 

[Gjo]

Yes, it does even though initially I ordered it without the optional module. As my amps and pre were being built at VAC in Sarasota, I mentioned the
the unit to Kevin, who wasn't aware of Space Tech Labs. He expressed an interest in trying one out & it just so happened to arrive a few days before the trip to Sarasota so brought it along still boxed up. I spoke with him yesterday and he'll try and set aside a few hours to run it thru its paces and give me his take on it and send it back.

I can't think of a better person to get an opinion from on the ATT 3.02 than Kevin. Especially since he has multiple legacy and modern testers to compare it with.

I'll start a new post on the ATT 3.02 once I hear back from Kevin and try it out for myself as well.

Bob

Please keep us posted (or send me a PM if you prefer).

I find myself needing a tester because mine presently is not working properly. As an audiophile hobbyist, the cost of the Space Tech Labs ATT 3.02 + 845 module is much more friendly than that of an Amplitrex.

Kevin's issue with the tube sockets is easily addressed with socket savers, IMO.

 

[keithc]

I can't think of a better person to get an opinion from on the ATT 3.02 than Kevin. Especially since he has multiple legacy and modern testers to compare it with.

I'll start a new post on the ATT 3.02 once I hear back from Kevin and try it out for myself as well.

Bob

Hi Bob:

Thanks for sharing about the STL. Did you consider a unit like the eTracer or uTracer?

Keith

 

[vintage_tube]

Hi Bob:

Thanks for sharing about the STL. Did you consider a unit like the eTracer or uTracer?

Keith

Hello Keith,

No Sir, I wasn't aware of those two testers which BTW look rather nice; however, maybe something I'd pursue if a bit younger (and steadier).

In response to my post mentioning Space Tech Labs ATT 3.02 -- it's still at VAC and several have tried it & liked it with the latest individual really interested to see if he can further delve into a bad tube, they have which their current testers cannot diagnose or pinpoint the spec that renders it as testing bad on a maximatcher, etc. With the upcoming Tampa audio show, they have other priorities and no time next week to use it - I suspect a good pro/con report nearer to 1st week in March & eventual return.

Bob

 

[Gjo]

With my vintage tester needing repair, and in the hands of Paul Hart, I had to make a decision whether to spend money to repair my top-tier vintage tester (which could potentially fail again down the road in my view...no disrespect to the talents of Mr. Hart), or put that money into a new tester.

I decided to buy the Space Tech Labs ATT 3.02 + 300B/2A3 module.

Wish some feedback about the Space Tech Labs ATT 3.02 had been forthcoming from VAC, but I had to make a choice.

Fingers crossed it was a good one.

 

[vintage_tube]

With my vintage tester needing repair, and in the hands of Paul Hart, I had to make a decision whether to spend money to repair my top-tier vintage tester (which could potentially fail again down the road in my view...no disrespect to the talents of Mr. Hart), or put that money into a new tester.

I decided to buy the Space Tech Labs ATT 3.02 + 300B/2A3 module.

Wish some feedback about the Space Tech Labs ATT 3.02 had been forthcoming from VAC, but I had to make a choice.

Fingers crossed it was a good one.

From my short but inquisitive conversations with VAC -- they like it & more than the maximatcher power tube testers they have (it doesn't have a regulated power supply; whereas the ATT 3.02 does.). So, that's somewhat reassuring to a degree.

If it turns out otherwise -- well, then there are two of us owning a dud.

Best Sir,

Bob

 

[Gjo]

ATT 3.0 + 300B/2A3 module

 

[Gjo]

I have had the ATT3.0 + 300b module for a couple of weeks.

A few observations:
1) The max. allowed test current for this tester is 100mA. There will be current limit if any test current is higher than that. For example, any regular tube rectifier that has a higher test current than 100mA (such as 225mA for 5U4G).

Per Al, if a rectifier tests 100mA in the STL 300b module, then that's considered normal and the tube is classified as healthy.

My question is, if one tests a rectifier in a full current tester and the tube tests 150mA when 225mA is "good" for that tube, would that tube be considered good? I certainly wouldn't buy it were it being sold by a re-seller.

On the other hand, it would theoretically test "healthy" (again per Al) in the ATT3.0 300b module since the tester would show 100mA. I don't know the answer, and I did not go down this path with Al.

If one is looking for full current testing, then one needs to look elsewhere. My previous Triplett 3444 tested rectifiers at full current.

2) If one owns a Space Tech Lab 300b (or 211) module, then a second DC power cable is used. Not a huge deal, but it gets a little restrictive if one doesn't have an available outlet nearby (the DC cables are relatively short...maybe 3 feet?), so a dual tap extension cord may be necessary.

3) Unlike vintage testers, and the Amplitrex, the ATT3.0 and associated modules do not have storage cases, so if that's important (it is to me), then one needs to buy a case. I bought a Pelican-style case with Pick-n-Pluck foam insert for about $75 on Amazon.

4) A note about Space Tech Lab's return policy...
While Al does accept returns within a reasonable window, the ATT3.0 is subject to a 10% re-stocking fee, and ancillary modules are subject to a 20% re-stocking fee. Shipping and insurance is the buyer's responsibility (as expected), and original S&H is not refundable (as expected). In my case, S&H from Canada to the USA was $110. A return would cost me $400+.

 

[vintage_tube]

Heard back from VAC and the bottom line is with the ATT 3.02 which has a maximum of 200v current it does not offer a true representation of a KT88/6550 tube under test and is approx. 350-350v less than what they operate a KT88 power tube at (560v).

VAC goes on to say it is ideal for 6SN7's, 6922, and 12v tubes such as the 12AX7/AT7/AU7 which I'm also interested in testing.

Bottom line, I'll keep the Maximatcher for power tubes (even though it only operates at 400v current & does not have a regulated power supply) and use the ATT 3.02 for the driver tubes & the like.

Best to all,

Bob