Tube Tester - Recommendations

I have now collected several sets of power, rectifier and pre-amp tubes that, when considering risk to damage of amp, age of run time and that I have to get them in matched pairs , if not quads (for ST-120 amp), I now think it may have ROI to invest in a process to test tubes.


Question:
1) Can you purchase tester such as https://orangeamps.com/wp-content/uploads/2014/01/Orange-Valve-Tester-Manual1.pdf which I googled and found. And test the three different tube types of ST-120. And so get not only pass/fail, but seems it can also grade them (technical understanding of how this is done would be helpful).

2) I assume a tester such as this would be able to test resistance, voltages etc.. and so get pass / fail. But can it , or some other means with use of multimeter, yeild data points to create a matched pair" Or does this take equipment beyond normal user resources? Maybe post some RTFM on how "Apex Matched" tubes are done.


Goal is to purchase a tube tester to get: (in order of complexity and value related to cost and gear / time)
1) Pass / Fail - Ex: VT-1000 $140
2) Scoring on life / quality of tube left - Ex: VT-1000 $140
3) Data point to create / combine into matched pair - ???
4) Data points to meet high standard such as "Apex matched" - ???



Thanks

penguinpages wrote:

I have now collected several sets of power, rectifier and pre-amp tubes that, when considering risk to damage of amp, age of run time and that I have to get them in matched pairs , if not quads (for ST-120 amp), I now think it may have ROI to invest in a process to test tubes.


Question:
1) Can you purchase tester such as https://orangeamps.com/wp-content/uploads/2014/01/Orange-Valve-Tester-Manual1.pdf   which I googled and found.  And test the three different tube types of ST-120.  And so get not only pass/fail, but seems it can also grade them (technical understanding of how this is done would be helpful).

2) I assume a tester such as this would be able to test resistance, voltages etc.. and so get pass / fail.  But can it , or some other means with use of multimeter, yeild data points to create a matched pair"  Or does this take equipment beyond normal user resources?  Maybe post some RTFM on how "Apex Matched" tubes are done.  


Goal is to purchase a tube tester to get: (in order of complexity and value related to cost and gear / time)
1) Pass / Fail - Ex:  VT-1000 $140
2) Scoring on life / quality of tube left  -  Ex:  VT-1000 $140
3) Data point to create / combine into matched pair  - ???
4) Data points to meet high standard such as "Apex matched"  - ???



Thanks

Skip this.
Testing tubes should be done at typical conditions. Cheapest way of testing / matching power tubes is a
maxi matcher.
Better buy already matched tubes and use rest of the money on records.

Tubes are consumables , be prepared to periodically replace them before they break.
As a general rule of thumbs, power tubes will be bad in 2000-5000h of use. pre tubes
such as ECC82 / 6an8 / 6u8 / 7199 will last much longer and will not degrade sound
until therir very end after maybe 10000h use.

Early symptoms of power tube degradation includes inability to keep bias steady, other symptoms is reduced output power.

My 1st post since my move and still chaotic unpacking and organization.
I would recommend getting a Jackson Model 648. They are easy to maintain and well known. Got mine and it was fully calibrated and came with a cal tube. I have since bought a newer cal tube and everything checks out.

Read over these pages:

https://maximatcher.com

Since 1998, I have been using a B&K 700 that has done all that I need for 25 to 30 tube types. I modified a socket 24 to properly test the 12AX7 tubes. This has been a great tester and I have 3 of them. I have owned the Dynaco originals since 1984. ST70, MKIII. I also have 2 Harman Kardons as well as HH Scott and many others. Although I buy matched power tubes, I modify the Dynacos to bias each power tube individually by adding the pots needed. The B&K is sufficient for all the tubes I use. Consider the B&K and you won't be disappointed. Tube are tubes. J.

Hi penguinpages

peterH says it correctly, tubes should be tested and matched at their working conditions. Unfortunately, that ain't easily possible. First, the tube needs to be properly warmed up, you don't set the bias when you first turn on an amp, testing tubes brings in the same considerations. Proper warm up is necessary. Personally, I let the tubes heat up for at least 10 minutes under working conditions, longer on physically larger tubes such as the 6550 or KT 120. Note the Orange tester specifically warns against testing warmed up tubes.

First question: are you testing them or matching them? If testing, then the standard testing conditions will give you feedback of their general condition. How they work in your specific application may be similar to the test results or somewhat different. Remember, whatever Hickok, B&K, Jackson, Triplette, etc say in their roll chart about what the settings to use, you really don't know what the voltage, plate current, and bias are to get the expected gm readings although it may be in the documentation. Also remember, the manufacturers stress that tubes can read +/- 20 percent of their rated specifications, making matching more difficult.

Second, you need to test at the working voltage. If you have 400 volts on the plates of an output tube, can you really match them up at the 150 volts a Hickok tester puts on them??? Do you know what plate current or screen current you are putting through the tubes when you test with a Hickok, B&K, Jackson, etc tester? If you are matching tubes, you need to mimic the conditions under which you'll be running them in your amp.  

I personally have two testers, a Bell Telephone KS-15560 which is a Hickok made to Bell Labs specs, essentially an upgraded Hickok 539 series (and rebuilt & modified by Paul Hart, here in Atlanta) which is my "portable" tester and a highly modified Triplette 3444 also rebuilt by Paul. This will test at up to 400 volts and requires a separate high voltage, regulated power supply and has secondary panel with a bunch of meters. I can set the plate voltage, bias voltage, the screen voltage, read the plate current, screen current, leakage and gm for the tubes. I use both the specs shown in the RCA Tube manual "Average Conditions" to test or if I know where the tube is being used, I can test it (and match it if necessary) under working conditions. I do have a 400 volt maximum limit however which means I can't truly match up the output tubes for my Dynaco Mark IIIs with 500 volts on the plate, but 400 volts is a lot closer than 150 volts...

Anyway, just some things to think about when you want to test or match tubes.

-Ed

For my use case.. The group here answered question:

Goal is to purchase a tube tester to get: (in order of complexity and value related to cost and gear / time)
1) Pass / Fail - Ex: VT-1000 $140 --> Possible but ROI for example tester may work but others recommended in $800 range ... this does not make sense (my current next step is to find a friend with tester in driving range but fails on matched pair check:)
2) Scoring on life / quality of tube left - Ex: VT-1000 $140 -> Seems to be same as above. I could rule one dead... or near dead.. but still left with purchasing pair matched online. So far I have a pile of 5 tubes "suspect" and just replace in matched pair. I mark them and
3) Data point to create / combine into matched pair - $800+ if even possible. So ROI is outside scope.
4) Data points to meet high standard such as "Apex matched" - Moving along... nothing to see here.

This discussion really did help though. So don't take response of ROI not worth it.. to mean discussion did not provide value.

I just don't know how to say " how many hours of play a set of tubes have had... so current path is:

1) Bias once a month
2) For main tubes... wait till one can't hold bias for 2-3 min. Purchase replacement in two match pairs as I guess... all four will be close to EOL.
3) For Rectifier tube.. pray when it blows... nothing else goes with it. have a spare or two waiting.

Tester should have voltages as close to working value as seen in your amp...and that limits your options. Never owned a Maxi.....I use Hickok 539C for pre tubes and built my own power tube tester that allows from 350 to 500+ plate voltage for current testing. Don't get too caught up in the weeds about values...it's all relative, IOW, if amp was built with 5-20% variation in component values, tested values won't necessarily equate same way once in amp....way too many variables. Get close, get least amount of background noise and enjoy the music!

This guy updated the Valve Heaven

to build a modern, fast, easy to use device that can test at real world conditions, something most testers can't or don't.

See Valve Tester




AND if you are testing old tubes run them on the heaters for 24 hours to degass.



See Tube Rolling Mythology.