Anyone Here Ever Purchased A Tube Tester?

Once or twice a day a tube sputters for a brief second in my Audio Research Reference DAC. The Reference DAC is connected directly to my amplifier and it also serves as my preamp. Visually, all of the tubes look fine. Visually, I can’t tell which tube may be bad.

The tubes are:     (4) 6H30, plus (1) 6550C and (1) 6H30 in power supply

Have any of you ever purchased a tube tester to test your tubes? If so, what tube tester are you using?


I own an Amplitrex tester, which is a fery good, albeit expensive, tester that tests at full plate voltage, which appropriately stresses the tube under test to give a realistic assessment of the tube.  It is also idiot proof and simple to use, unlike testers that require one to look up the tube in a table and then manually set various dials and buttons as instructed by the table; you select the tube type from a menu, and all parameters are automatically set.  The readiut not only gives real values (not an arbitrary scale), it also gives you the expected value and an interpretation of the values (strong, weak, etc.).  Hook it up to a computor and it can trace the tube.

I have not tried the Etracer tester from Taiwan myself, but a big time expert who owns many different testers really likes it.  It comes either as a kit or an already built unit.  It has to be used with a windows computer.  It traces the tube as well as provides numeric values.  The expert said that its measurements agree very closely with that of the Amplitrex , but its tracing software is better and gives easier to read results.  However, one has to set jumper wires to configure the tester to the type of tube under test, so it is not as easy to use as the Amplitrex.  Still, this expert said he is considering selling his Amplitrex in favor of the Etracer.

I have a Hickock tube tester I bought years ago from Andy Bouwman at Vintage Tube Services.  He had calibrated it, which I believe to be important with the older testers.  In addition to the drawbacks that larryi mentions, another drawback to an older one like this is that it may not  work with some of the newer tube types like your 6H30 (or at least it won't show it on the tube types on the tester's table that you use to set the type), but it does work well with the types I used it for in the past.

The Hickock TV7 was one of the types the expert I talked to liked.  He had concerns with several of the people he used to calibrate some of the units he had, finding that the results did not quite match up with other testers.  I suspect he was more inclined to pick among the MANY TV7s he has that proved to give good results (test results matching up with performance of the amp) and not do much in the way of calibration.  

A young friend of mine has a TV7 that he recently had re-calibrated.  The person who did the work is a friend who knows his stuff who was somewhat reluctant to do the work because it is very time consuming.  When he got the unit back, he also got back a bag full of parts that had to be replaced--it seemed like a lot of work was indeed involved in calibration.  I have used the TV7 at my local area shop, but it is a bit of a challenge to do the settings based on the charts supplied (I need to triple check everything I do so I don't accidentally cook the tube).  The people at the shop have the settings memorized for common types and they zip through the settings.

One piece of advice, if you do a lot of testing, buy socket savers so that the socket that wears out from tubes being inserted and pulled out is that of the socket saver and not the tester.  I spoke with an old tube guy who said that even good sockets may start to go bad after 30 or so insertions--in the days before people went crazy over trying different tubes, 30 insertions probably meant more than 30 years of use, which is not the case today with some tube gear, and certainly not the case with a tube tester.

I’ve been into tubes for nearly 35 years and never felt the need. Sputter, as you described it occurs frequently and I believe caused by pin/socket connections, not bad tubes. I check my tubes and just wiggle the tubes a bit and it usually goes away. FWIW.

I also own the Amplitrex. It is pricey, but very easy to use and has been very helpful in sorting out the weak tubes. 

i use a lowly B&K but in your case, The ability to properly test the 6H30 is key. I would invest in a backup set from ARC including the key 6550 in the power supply of your DAC, it is way more life limited than the 6H30. Then find a reliable vendor / ARC dealer w tester and have them grade your old tubes. 

A friend and member of my local HiFi Club has a substantial tube collection with items spanning two generations of collecting. 

A Calibrated Tube Tester is a important part of this enthusiasts activities.

It is great to be introduced to same era Tubes with usage life beyond factory spec' and almost perfectly matched in each half of the Valve across Valve Pairs or Quads. 

It is only through being introduced to same Brand Valve as per the above and then compared to same Brand valves with a reduction in usage life and a wider range in the readings across each half of the Valve, does one discover the real attraction of very accurately match Valves.

It is something quite special to experience a near perfect match array of Tubes. Having access to the Tube Tester for periodical readings helps greatly with assuring the optimised experience of Valves is being maintained. These Types are usually the Sunday best and lesser quality matches are identified do the daily grind/glow.

@mitch4t Tube testers will not find a sputtering tube. The best way to find it is to swap it with the other channel if that is possible, if not, with another tube of the same type elsewhere in your system.

It can also be a corroded tube socket as previously suggested, but IME your DAC is far too new for that to be an issue. The tube itself is far more likely.



I run dome very old tubes in my system.  Once every three or do years, I get brief sputtering or crackling sounds that then goes away.  I asked the builder about this and he said something inside the tube flaked off and fell onto the heater and the tube will make that noise for a few seconds or minutes until the flake burns up.  He said it is no big deal.  

I frequently blab about everyone who has tube equipment getting an inexpensive tube tester.

I bought this Accurate Model 257 for a friend.


It's results matched the results of my smaller model 157. My Model 157 always matched my big heavy Jackson, so I gave the Jackson to a friend who used to bring his tubes here.

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I had one briefly that had three more knobs than the space station cockpit. I sold it to somebody hopefully smarter and more committed than me, which would not have been hard..,

When I started playing with 4 pin DHT and rectifiers I bought a Hickok 800.   It looks like it should be in a museum, it's that nice.  It was serviced not too long ago and have saved me from using a bad tubemore that once.  It paid for itself by not allowing tubes to damage my gear.   

I use a cheap vintage tester, Superior TD65 purchased on eBay and it gives me what I need to know and works fine. I highly suggest anyone with tube gear get one. It doesn’t have to be a very expensive one, but one that will tell you if a tube is bad, weak, or not. 

Transcendental Sound used to sell a kit which I built and have been using for several decades. I can't imagine living without it.

@larryi I'm jealous. Been wanting the Amplitrex for a while now. Certainly the best currently available.


I bought a Beck Elektroakustik RM-1 tube tester in 2015. It was customized for the main tube types I use in my system. It works well and the support is good. However it does not test the tubes for background noise.

I have several Hickok testers as well as several Sencore testers. My hands down choice for go/no-go testing is a Sencore, with its grid leakage function. I have an ARC Anniversary pre as well as Atmasphere amps. My 6550’s usually get about 2500 hours and the 6h30 about 6000 hours before they indicate bad on the grid leakage test and require replacement. ARC recommends replacement at 2000/4000hours respectively. 6nsp can also be subbed for the 6h30 if you want to try rolling. I wrote down my various tube settings on a piece of paper…tube lookup in the tables each time is no longer an issue. Grid leakage should be done after a 15 minute warmup period or so or the indication will not be representative or even close. Same with emissions or any other test but especially the grid leakage test. 6h30 can be tested using 6dj8 settings for go/no-go testing which my main focus is…Hickok has additional dial setting which I don’t have in front of me…

I just think you leave yourself ’blind’ without a simple inexpensive tester.

For most of us, we don’t know detailed measurements. When something is amiss, quickly check tube: short? strength? strength matched to other ’matching’ tubes?

Buy new or used tubes, test them, supposedly matched tubes, test them.

IF you are tempted by the simple type, like the Accurate 257, I will have my friend check the booklet to verify it can test your tube types.

I look for shorts, and strength on the meter, and if strength matched. As I said, my Accurate Strength always matched the big heavy Jackson’s results, so I gave the Jackson away.


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While it's nice to know how strong a tube is, it even more important to test for internal shorts .   I always test the filament and test for shorts before checking emissions.   

For that reason alone it's worth having one if you have several pieces of tube gear.    Don't use your Amp as a tube tester

I have a TV-7 and 3 other Hickoks.  The only drawback to any of these vs the Amplitrex, Etracer, and Maximatcher is the relatively low plate voltage applied to power tubes is insufficient for matching.  In a recent test of rare 8417 tubes, I used my 539B, which allows plate current monitoring.  After recording the data for each of 12 tubes, I took them to a friend's house who has a tester with up to 500 v on the plates, and meters on every element in the tube.  Over half of the theoretical matches my 539B predicted were wrong.  The TV-7 and similar Hickoks are fine for preamp tubes and detecting shorts in all tubes, but for matching, you need a higher plate voltage.  I'll probably get an Etracer kit at some point.    



I purposely avoid knowing stuff, so I can make decisions that are 'good enough', like a simple tester.

If it sounds damn good, like my Sony xa5400cd player I got with help here, I don't want to know about anything else, unless it breaks. I probably would just buy another xa5400 without even looking at anything else.

I had a big Hickock, and the Jackson I mentioned, never went beyond shorts/strength/matched strength? Big, took more space, heavy, not easy to take to a friends house ...

After 'little accurate 157' simple short/strength answers were ALWAYS the same, I gave both the Hickock and Jackson away to friends.

I have a LOT of used tubes, hundreds, some of them actually new. I test them before giving to friends, or using myself, a few for the 2 Fisher 500C's I'm going to sell if I overcome my reluctance to ship.

I'm between NYC and Philadelphia, perhaps I will try pickup only. 

Another way, compared to buying an old tube tester, is buying a new one, tailormade for you. I did, some years ago - Beck RM-1 tube tester, made to order by Helmut Beck for the 8 main tube types in my system. A quality instrument with great support from Beck. Very easy and quick to use. But limited - it only measures emission, not the noise level of the tube. Yet I get some info on the tubes (more or less 'strong'), relevant for matching and evt replacing, and I avoid putting bad tubes into the system. Recommended.

I found a Healthkit TT-1A tester a few years ago that had been recently restored by a shop that understood this device. I don't use it often enough but it's great and (relatively) easy to use. It will test *almost* any tube made through 1978, including DHT and Nuvistors. It's a bit of a cumbersome beast. The paper rolls are in good shape but I find it easier to lead digital files on my laptop or access from a tablet.

Yesterday I tested all the 19 tubes in my preamp with the Beck RM1 tester. I found three 6922 tubes that measured very weak, and replaced them with spares that tested ok. I was rewarded with better sound. What is interesting is that I had not really noticed that the sound had become a poorer, more muffled, closed-in. Until I replaced the weak tubes. Then, the benefit was obvious. So I told myself - good idea to do this more often!

I know that the RM1 is limited, but in this case it worked well. The meter readings corresponded to the sound. So, I will have to buy three 6922s, not a full set of 18 6922s plus 1 12au7 (expensive for NOS). RM1 also catches bad tubes, including 6as7g, before I put them into my amplifier. I avoid tubes creating errors in the amp or preamp. RM1 doesn’t test transconductance or noise, but has actually saved me money over some years of use.

Whatever the tube tester, you may be able to develop your own system for testing the things it doesn’t test. Like the background tube noise level. I have a strict procedure, measuring the noise level of the tubes in my system with a db meter, compared to a standard reference (with volume loud, not playing music, with the tubes in my very noise-sensitive phono preamp). In case of dispute I can send the measures to the seller, to get my money back. A year ago I got a quad Telefunken that sounded good but had too much noise. I had to return them. I was sad and the seller was irritated ("but they test strong!").


My noise level test is done in a very demanding context. The phono preamp has three tube gain stages, and the first is stretched to the utmost - amplifying the weak signal from the cartridge. Each stage has four 12ax7 tubes, two per channel. This is a very puristic solution and when all is right it sounds wonderful.

I know that I can use "mild offenders" in the phono noise level test elsewhere in my system, without obvious defects. If a 12ax7 sounds good in my phono it will sound good in my headphone amp too, and there, I don't hear the noise problem (or not much).

I have a quad of NOS Philips Herleen 12ax7 that measure very strong and have good sound. At first, the noise level was quite acceptable, but over 1-2 years it became higher, and I had to take them out of the phono preamp. I am not sure what to do with them.

The background tube noise, in my system, is always there, if I turn the volume towards max, with no music playing. Almost all the noise comes from my phono preamp, even if the preamp and the amps - both tubed - contribute too. In practice the digital input sounds silent while the analog input has noise, more or less. To hear this noise, unless the phono tubes are noisy, I have to turn the volume up. It is not so easy to hear when playing music, although it appears in quiet passages. It is my strong conviction that this background noise is NOT what I want, even when it is not so easy to hear. It intrudes on all the rest. The music becomes less stable, less at rest, less undisturbed. Often called "black background". Not sure why, since I dont hear it as "black". What I hear is less noise.

Athough the diagnosis may be complex - what noise, exactly, and why - it is easy to hear, with the volume up loud. It may start with a slight sense of 'wind' in the sound, developing into a 'storm' in the noisy cases. The tube noise can also resemble cooking. When a tube has developed cooking sounds it is usually on the way out of the my system.

What I don't know, is whether it is good practice to use moderately noisy but good sounding tubes in less critical positions in the system. Or is it best avoided.