Your Eico tester may be the first tube tester I ever owned. Either that or a 625, Can't remember. But over the years I've owned many different types. Currently I have:
For receiving tubes:
Hickok USM-118B cardmatic (my favorite because it's fast)
Hickok 539C (my favorite manual type)
Hickok 1575B (similar to 539C w/cathode bias resistors)
Hickok 752A
B&K 700 (also easy and fast setup)
2 Tektronix 570 curvetracers (late round corner versions w/5K+ S/Ns)
For transmitting/industrial tubes:
A rack mounted system, with various plug-in sockets, for steady class-A tests up to 1500 watts input. (<5kv) Gm is measured with a 1Khz 1v reference signal. All elements are monitored.
A second rack mounted pulse system (<2500v) for 2500 watt tubes and up. Peak amps measured with sample & hold peak detector. (analoge meter) Maximum filament power is 200 amps or 1500 watts. (The limit of my AC mains.) This system also tests large rectifiers and thyratrons on a CRT display using isolated AC. (<10amps)
I could put up a pix or two if anyone is curious. (Yes, I've been doing this a long time)
Victor
For receiving tubes:
Hickok USM-118B cardmatic (my favorite because it's fast)
Hickok 539C (my favorite manual type)
Hickok 1575B (similar to 539C w/cathode bias resistors)
Hickok 752A
B&K 700 (also easy and fast setup)
2 Tektronix 570 curvetracers (late round corner versions w/5K+ S/Ns)
For transmitting/industrial tubes:
A rack mounted system, with various plug-in sockets, for steady class-A tests up to 1500 watts input. (<5kv) Gm is measured with a 1Khz 1v reference signal. All elements are monitored.
A second rack mounted pulse system (<2500v) for 2500 watt tubes and up. Peak amps measured with sample & hold peak detector. (analoge meter) Maximum filament power is 200 amps or 1500 watts. (The limit of my AC mains.) This system also tests large rectifiers and thyratrons on a CRT display using isolated AC. (<10amps)
I could put up a pix or two if anyone is curious. (Yes, I've been doing this a long time)
Victor
I have two tube testers around here somewhere. One is an Eico, and the other is a Hickok. Both are mutual conductance type. I use the Hickok occasionally. I have found that when testing a batch of random used tubes about 5% of tubes that tested good in the tester had problems when used in an amplifier. The usual problem is high distortion, low gain, or low output. When the tube tester says the tube is bad, it usually is.
If I have a bunch of the same tube to test, I will rig up a test fixture that biases up the tube to a reasonable current and runs a signal through the tube. The output goes to a scope and a distortion analyzer. The distortion readings vary a lot for some tube types, and are a lot closer for others. 6AU6's in triode are all over the place.
If I have a bunch of the same tube to test, I will rig up a test fixture that biases up the tube to a reasonable current and runs a signal through the tube. The output goes to a scope and a distortion analyzer. The distortion readings vary a lot for some tube types, and are a lot closer for others. 6AU6's in triode are all over the place.
I was thinking of a POOGE for the EICO tube tester I own -- sort of incorporating the microprocessor device I described in AudioXpress about 5 years ago -- the great thing about any of these testers is that you have all the sockets and filament wiring ready to go, and the leakage test is accomplished with the press of a button. The grid and plate potentiometers are already there.
I have about 20 more or less tube testers, its a sickness I have, you can see 15 of them at http://tuberadios.com/tubetesters.html
Not shown is a B&K 707, Eico 635, Precision 855, NRI model 70 and probably 2 others I forget. I came close to buying a Hickok 539B 2 months ago but the seller backed out..
Regards,
Sal
Not shown is a B&K 707, Eico 635, Precision 855, NRI model 70 and probably 2 others I forget. I came close to buying a Hickok 539B 2 months ago but the seller backed out..
Regards,
Sal
I have a Hickok 533A and a 546,
a Jackson 648S, and a FUBAR Eico 666.
I have resently restored a Precision 10-12, Jackson 648("A"),
Eico 666, B&K 500x2, B&K 700, B&K 607, B&K 667, Sencore 109,114,142, Accurate Instr. 151, Mercury 204 (=Eico 660), TV-4,
And have been stiffed on epay for a Hickok 752, a Hickok 600A and Jackson 648S (never arrived).
Arne K
a Jackson 648S, and a FUBAR Eico 666.
I have resently restored a Precision 10-12, Jackson 648("A"),
Eico 666, B&K 500x2, B&K 700, B&K 607, B&K 667, Sencore 109,114,142, Accurate Instr. 151, Mercury 204 (=Eico 660), TV-4,
And have been stiffed on epay for a Hickok 752, a Hickok 600A and Jackson 648S (never arrived).
Arne K
fernando_g said:
Terminal disease, that is...
I was most impressed with the self-service unit. Once commonplace, I bet they are now scarcer than hen's teeth, more so in such a complete state.. Anyways, what year do you think it was manufactured?
The paperwork I have with my self service Eico 660 (Mercury 204) tube tester is dated 1969.
Regards,
Sal
I have a couple heathkits, but mostly I use a Mercury 2000 which seems to work well.
But when testing tubes, I get a bit confused. If I test known NOS tubes of the same type, I do not understand the readings when brand by brand the average data varies.
12AX7's being some I had tested today. I tested a bunch of 60's RCA 12AX7's all of which measured an average of 1100+/- 2% microhms on my tester.
The book for the tester say 1000 is good.
Then I tested a bunch of NOS Brimar CV4004 / 12AX7 which all averaged around 1000 microhms.
Now, does this mean the Brimars are not NOS? I personally removed them from the shrink wrapped packaging.
Then I tested a bunch of JJ 12AX7's, The readings were all over 1200 microhms.
I am somewhat confused by this because it tells me nothing other than the tube curently functions and give me no real usable life data?
Trout
But when testing tubes, I get a bit confused. If I test known NOS tubes of the same type, I do not understand the readings when brand by brand the average data varies.
12AX7's being some I had tested today. I tested a bunch of 60's RCA 12AX7's all of which measured an average of 1100+/- 2% microhms on my tester.
The book for the tester say 1000 is good.
Then I tested a bunch of NOS Brimar CV4004 / 12AX7 which all averaged around 1000 microhms.
Now, does this mean the Brimars are not NOS? I personally removed them from the shrink wrapped packaging.
Then I tested a bunch of JJ 12AX7's, The readings were all over 1200 microhms.
I am somewhat confused by this because it tells me nothing other than the tube curently functions and give me no real usable life data?
Trout
Hello Trout,
I'm of the opinion that what you've experienced with testing these tubes of various makes and vintages is quite normal. Yes, tubes are made to a specification, but there are tolerances to these. My years of experience with testing leads me to believe that there are no tight, hard and strict boundaries. Especially between countries.
Your RCA's and Brimars are within 10% of each other. Not unreasonable I would think. I would be more concerned if they were 50% off. And as for the Chinese stuff....phew! I'm from the old school and remember the beginning of their imports. They couldn't hold a tolerance for beans! (I'm being very kind here) I guess they've gotten better with practice so 20% is probably ok for them. It seems like what once were specifications are now just guidelines.
Victor
I'm of the opinion that what you've experienced with testing these tubes of various makes and vintages is quite normal. Yes, tubes are made to a specification, but there are tolerances to these. My years of experience with testing leads me to believe that there are no tight, hard and strict boundaries. Especially between countries.
Your RCA's and Brimars are within 10% of each other. Not unreasonable I would think. I would be more concerned if they were 50% off. And as for the Chinese stuff....phew! I'm from the old school and remember the beginning of their imports. They couldn't hold a tolerance for beans! (I'm being very kind here) I guess they've gotten better with practice so 20% is probably ok for them. It seems like what once were specifications are now just guidelines.
Victor
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