Tube Testers

[MylesBAstor]

Deleted

 

[Albertporter]

Does everyone with tube gear own a tube tester to check for bad tubes?

If so, what tube tester are you using?

Hickok 752A restored by Roger Kennedy in California. Good machine but like most tube testers of this era they don't always put enough voltage on power tubes to find all the shorts.

 

[Jay_S]

Good topic. I'd like to see some recommendations. I don't have a tester but I have lots of spares, particularly small signal tubes.

 

[kach22i]

No tube tester here.

I wonder if my uncle still has one, he used to fix TV sets in the 1960's.

 

[Gregadd]

I do not own it but... NSGARCH sent this to me.

http://www.audiophile-gift.com/

 

[MylesBAstor]

Lol....

 

[nsgarch]

But Greg, that's a digital clock, not a tube tester! (unless you're testing those numerical nixi tubes ;--)) I do have a Hickok 6000A which is a nice reliable tranconductance tester (doesn't test tubes for plate current, however.) If I were going to spend over $1000 on a tube tester, I would definitely buy a new digital Amplitrex http://www.amplitrex.com/index.html They're $2500 but totally accurate, can measure any tube at full operational power, and they're a snap to use because all the tube data is loaded in memory, and easily updated. When you think that (what I consider) the next best thing, a used Hickok 539C, go for $1500 and up on eBay and still need to be refurbed and calibrated, the new Amplitrex equipment starts to look not so bad -- in fact many if not most of the online tube sellers are switching over to the Amplitrex units. The fact that there's a waiting list for them speaks for itself.

 

[c1ferrari]

Hi Myles,

I'm using an Amplitrex AT1000. I brought it with me from California when I visited Albert Porter and Fred Crowder in Texas. Unfortunately, I'm not conversant with the unit and need some quality time to achieve a better operational feel for it. In that context, I believe it to be an authoritative instrument; however, one must know what to do with the information and whether it is germane to a specific circuit, as I understand it.

Vbr,
Sam

 

[Albertporter]

Sam, It DID find the shorts that other testers failed to show.

 

[Gregadd]

But Greg, that's a digital clock, not a tube tester! (unless you're testing those numerical nixi tubes ;--)) I do have a Hickok 6000A which is a nice reliable tranconductance tester (doesn't test tubes for plate current, however.) If I were going to spend over $1000 on a tube tester, I would definitely buy a new digital Amplitrex http://www.amplitrex.com/index.html They're $2500 but totally accurate, can measure any tube at full operational power, and they're a snap to use because all the tube data is loaded in memory, and easily updated. When you think that (what I consider) the next best thing, a used Hickok 539C, go for $1500 and up on eBay and still need to be refurbed and calibrated, the new Amplitrex equipment starts to look not so bad -- in fact many if not most of the online tube sellers are switching over to the Amplitrex units. The fact that there's a waiting list for them speaks for itself.

This sounds as though it would be one of those items that would be ideal for a group or club purchase. I remember when record cleaning machines were purchased that way. Now of course we all got rich and can afford our own.

 

[MylesBAstor]

OK so here's anothe question. Do you believe the tube tester should tell how the tube performs in the circuit or is the final determination how the tube actually performs in the circuit. To wit, cj could by an amplitrex, test the tubes and then just sell them. Instead they burn them in for a period of time (I think it's 48-72 hours) after which they test the tubes in the actual circuit.

Guess that brings something else in. How many do a controlled burn in before testing the tube and if you have, is there a difference?

 

[c1ferrari]

Sam, It DID find the shorts that other testers failed to show.

Absolutely correct, Albert. The Amplitrex is a fine instrument, indeed. Other than very basic functions, I have yet to explore the capabilities of the unit. For me, the next step in my evolution is to accrue a fundamental understanding of valve anatomy, lexicon, operation, and specific circuit design. The objectives would be to determine if the data are intelligible, relevant, and develop a correlation, if possible, between what is heard and measured!

Regards,
Sam

 

[jcmusic]

I am using a Hickok 6000 to do my testing, I have not done any testing lately no need. That is soon to change because of the new amp!!!

Jay

 

[stellavox]

Regarding Tube Testers

I like to think of a tube tester as more of a go/no go device. Most do a good job of detecting shorts but you have to be careful in interpreting the results of a "quality test"; i.e. a "questionable" tube may work perfectly well - or be unworkable in a particular application.

And has been pointed out, most testers check the "gain" at only one point on the curve - which could be totally different from the circuit you are using it in. You can "match" tubes but only at that ?? operating point.

I use my Hickok 539B to "grade" tubes - from OK through maybe "better" and mark the transconductance on the side with a magic marker. Then play with them in a particular application to find which "sounds" best.

For preamp front-ends where low noise in important - most testers don't test for this. I think that the Hickoks and some other brands have some kind of noise test capability, but have never checked it out to see if the "measurement" correlates with actual perceived noise levels. Again I use my ears for this.

BTW, I always "clean" the tube pins with Cramolin and before trying to remove any excess, I put the tube back in the socket and circle it around a bit (or pull it up and down a few times) to "clean" both the tube pin and the socket. It really quiets down the tube/socket connection/interaction.

Charles

 

[jcmusic]

I like to think of a tube tester as more of a go/no go device. Most do a good job of detecting shorts but you have to be careful in interpreting the results of a "quality test"; i.e. a "questionable" tube may work perfectly well - or be unworkable in a particular application.

And has been pointed out, most testers check the "gain" at only one point on the curve - which could be totally different from the circuit you are using it in. You can "match" tubes but only at that ?? operating point.

I use my Hickok 539B to "grade" tubes - from OK through maybe "better" and mark the transconductance on the side with a magic marker. Then play with them in a particular application to find which "sounds" best.

For preamp front-ends where low noise in important - most testers don't test for this. I think that the Hickoks and some other brands have some kind of noise test capability, but have never checked it out to see if the "measurement" correlates with actual perceived noise levels. Again I use my ears for this.

BTW, I always "clean" the tube pins with Cramolin and before trying to remove any excess, I put the tube back in the socket and circle it around a bit (or pull it up and down a few times) to "clean" both the tube pin and the socket. It really quiets down the tube/socket connection/interaction.

Charles

Charles,
What is Cramolin and where do I get it?

 

[MylesBAstor]

I like to think of a tube tester as more of a go/no go device. Most do a good job of detecting shorts but you have to be careful in interpreting the results of a "quality test"; i.e. a "questionable" tube may work perfectly well - or be unworkable in a particular application.

And has been pointed out, most testers check the "gain" at only one point on the curve - which could be totally different from the circuit you are using it in. You can "match" tubes but only at that ?? operating point.

I use my Hickok 539B to "grade" tubes - from OK through maybe "better" and mark the transconductance on the side with a magic marker. Then play with them in a particular application to find which "sounds" best.

For preamp front-ends where low noise in important - most testers don't test for this. I think that the Hickoks and some other brands have some kind of noise test capability, but have never checked it out to see if the "measurement" correlates with actual perceived noise levels. Again I use my ears for this.

BTW, I always "clean" the tube pins with Cramolin and before trying to remove any excess, I put the tube back in the socket and circle it around a bit (or pull it up and down a few times) to "clean" both the tube pin and the socket. It really quiets down the tube/socket connection/interaction.

Charles

Good points all as usual Charlie. That's why I think for instance cj supplied original/replacement tubes (and I'm sure ARC, etc do the same thing) are tested in circuit for performance. In that way, they can also select for low noise for critical phono section applications.

 

[cjfrbw]

I have had a B&K 707 tubed tube tester since 1991, use it all the time. I have adapted it to test four pin triodes as well when necessary. Standardization is over rated, you really just need tube strength, shorts and matching, otherwise just see if it works in your circuit. A tester won't tell you if a tube is noisy.

 

[stellavox]

Cramolin

Charles,
What is Cramolin and where do I get it?

Jay,

Cramolin or "Deoxit", made by Caig Labs is a product classified a contact cleaner or "enhancer". I get mine from MCM Electronics. It is available in a variety of forms but I use the the 100% (versus diluted) "red" that comes in a little squeeze bottle, with a hypodermic-type tip which is useful in getting it into "tight" places.

The idea is to put it on (or "wet") a contact, wait a few minutes, then remove as much of it and the "bad" residue as you can with a tissue or Q-tip. I routinely use it when working on "classic" hi-fi equipment - on tube pins, switch contacts, input/output connectors and in "quieting down" noisy volume/balance/tone controls. It really works. From time to time I also use it to "clean" all the interconnect/speaker contacts on my system.

Please understand that its use is controversial, with detractors claiming adverse sonic effects.

Caig also makes a "green" solution which they recommend applying after finishing the red treatment. It is supposed to "preserve" the cleanliness of the contact by delaying corrosion. I don't use that.

There are other similar products - "Tweak" comes to mind - if it is still being made.

As a sidebar: I had a conversation with Paul Jayson of Viola Labs on this "contact" issue - as it relates to interconnects. For those who remember - most all the input/output connections on "early" equipment used tin or nickle plating which would severely corrode over time (in some cases a relatively short time). Paul opined that one benefit of newer technology is that the materials used in "modern" connectors is just "better" (let's not go into why) - in general they have less sonic "baddies" AND the cable/equipment connections can go much longer without "maintenance". Like every so often unplugging and re-plugging everything on your system.

Happy almost Summer

Charles

 

[Steve williams]

along the same line I mention Lloyd Walker's SST Extreme which is a silver paste. Almost impossible to ever remove from the contacts. Some say that its use could void a warranty on a component sent back for repair if their is silver paste on the contacts

BTW, I have used Deoxit for years and like it. I have never used the green

 

[stellavox]

Clarification Steve,

Is it a paste containing silver, or a paste to be used to clean silver - and/or other "precious " metals?

I can understand that when applying some kind of paste (versus a liquid) you will NEVER be able to remove all of it - let alone whatever residue it creates. I'd steer WAY away from that.