Hickok vs B&K Tube Tester

[cabinet]

Hi,

I just bought a B&K 707 tube tester and now am looking for a Hickok, its my understanding that if you really want to match tubes good, to go with a Hickok or something made by them.

My knowledge base is not that great in this area, so any help or opinions would be great. My main use will be for receiver/amp tubes with old Fishers and Scott's. But matching is a side benefit -- anyways should I spend the dough and what models of Hickok do you recommend.

Thanks,

Dan Crosby

 

[Rivieraranch]

Hickok 6000 6000A

You could not go wrong with a Hickok 6000 or 6000A. They are portable and test the newer tubes in the receivers that you mentioned.

 

[NOSValves]

None of the vintage tube testers are really good at fully matching tubes especially output tubes. First of they do not run the tubes at the same electrical conditions that the tube will experience in the real world. Very few vintage testers give any kind of current matching just mutual conductance. For output tubes one needs something like a modern maxi matcher.

Craig

 

[PakProtector]

hey-Hey!!!,
No plug in tester, save for the Tektronix 570, or perhaps its modern analog applies anything like operating voltage and current. For power finals at the lower voltages testers use, the plate current is fairly small compared to what it would see in-circuit.

The change in properties as voltage and current increase is somewhat predictable. So, if at a 'tester OP' the valves match, you get *SOME* information. Some is better than none, and depending on the circuit, may be enough.
cheers,
Douglas

 

[soundmotor]

The Hickok Cardmatics and 539's were sold as suitable for tube matching in any industrial or laboratory application. These were the ones the Bell System used exclusively as well. They were roughly 3-4X more costly than the typical testers a TV repair shop had such as the 600/6000 models. You are lucky if you can find a complete 539C for under $1K now. I believe that military TV-2, TV-7, & TV-10 will also match.

 

[salb203]

I am eagerly waiting for my Hickok 539B to arrive in the mail... I do have a Signal Corps I-177a, Hickok 600A and B&K 707 mutual conductance testers in my dungeon..

The Hickok 539b or c was a tube tester I always wanted.

Regards,
Sal Brisindi

PS: In reality, to match tubes you would want a higher plate voltage in the area of 450 volts instead of 250 volts the 539b will test a tube at.

 

[goldear]

The Hickok Cardmatics and 539's were sold as suitable for tube matching in any industrial or laboratory application. These were the ones the Bell System used exclusively as well. They were roughly 3-4X more costly than the typical testers a TV repair shop had such as the 600/6000 models. You are lucky if you can find a complete 539C for under $1K now. I believe that military TV-2, TV-7, & TV-10 will also match.

While I would love to own either the 539 or the cardmatic units that you mention, these will not match tubes anywhere near their true operating points.

The 539C has the extremely rare plate current test feature, which is necessary for proper tube matching, but even at 250V (which is about 100V higher than most Tube Testers will go), it is far from optimum when the true conditions of the circuit are going to operate that tube at around 500V. Plus check the settings on your hickok: I'd be willing to bet money on the fact that all of its built-in power tube settings test the tube at closer to 150V. Usually the 250V tests are only used for testing leakage in my experience.

Some of the military testers will give you GM readings, but unfortunately GM is not the correct reading to use to match power tubes: Plate current is. :yes:

 

[soundmotor]

While I would love to own either the 539 or the cardmatic units that you mention, these will not match tubes anywhere near their true operating points.

The 539C has the extremely rare plate current test feature, which is necessary for proper tube matching, but even at 250V (which is about 100V higher than most Tube Testers will go), it is far from optimum when the true conditions of the circuit are going to operate that tube at around 500V. Plus check the settings on your hickok: I'd be willing to bet money on the fact that all of its built-in power tube settings test the tube at closer to 150V. Usually the 250V tests are only used for testing leakage in my experience.

Some of the military testers will give you GM readings, but unfortunately GM is not the correct reading to use to match power tubes: Plate current is. :yes:

Those machines however, especially the Cardmatic, were sold as suitable for tube matching back when they were new. Perhaps Hickok was engaging in marketing although I suspect not. Surely portable equipment that was capable of tube matching is not something that just came with the advent of the PC? Maybe the conditions those machines matched under were good enough? I am also curious as to the source that says tubes must be tested at higher voltages. Where does that come from?

 

[NOSValves]

Those machines however, especially the Cardmatic, were sold as suitable for tube matching back when they were new. Perhaps Hickok was engaging in marketing although I suspect not. Surely portable equipment that was capable of tube matching is not something that just came with the advent of the PC? Maybe the conditions those machines matched under were good enough? I am also curious as to the source that says tubes must be tested at higher voltages. Where does that come from?

Yea they were but I personally believe they were designed for matching brand new tubes of the day that had some what better predictabilty in comparison once the true current and plate voltage was applied. With todays NOS market which is more likely used NOS these tubes can test wonderful in the tube tester and then run away when placed in the amp or be way off current wise. Been there done it and seen it. I own 4 different hickok tube testers, one EICO and a B&K 707. When it comes to used output tubes I don't trust a one of them. I test them for obvious problems in the tube tester and then check them for reasonable performance and matching in the circuit.
Of course all of what I'm saying is in reference to output tubes. Small signal tubes the results in most testers are just fine.

Craig

 

[soundmotor]

Yea they were but I personally believe they were designed for matching brand new tubes of the day that had some what better predictabilty in comparison once the true current and plate voltage was applied. With todays NOS market which is more likely used NOS these tubes can test wonderful in the tube tester and then run away when placed in the amp or be way off current wise. Been there done it and seen it. I own 4 different hickok tube testers, one EICO and a B&K 707. When it comes to used output tubes I don't trust a one of them. I test them for obvious problems in the tube tester and then check them for reasonable performance and matching in the circuit.
Of course all of what I'm saying is in reference to output tubes. Small signal tubes the results in most testers are just fine.

Craig

Is it confined to tetrodes & pentodes output tubes that are unsuitable to be matched with one of these rigs? Most triodes & triode-connected finals run at the B+ these tube testers operate at. Could it be extrapolated that if they test fine under those conditions that they would also be OK at higher B+?