I have a Hickok Model 600A tube tester that I'm learning to use. Hopefully someone here can answer a question for me. On the micromho meter there are 3 scales that with good ranging from:
When I'm testing a 6DJ8, 6922, 7308 etc. and the scale is pegged past any of these 3 different groups of numbers. Which range should I be using? If it this range ---{7000-15000}--- and the meter was as far past 15000 as it could go. What's exactly is it telling me about a tube if it was a 60's Siemans gold-pin 6922, besides it measures better than new?
Thetubeguy1954
~Rational Subjectivism. It's An Acquired Taste!~
- 1500-3000
- 3000-6000
- 7000-15000
When I'm testing a 6DJ8, 6922, 7308 etc. and the scale is pegged past any of these 3 different groups of numbers. Which range should I be using? If it this range ---{7000-15000}--- and the meter was as far past 15000 as it could go. What's exactly is it telling me about a tube if it was a 60's Siemans gold-pin 6922, besides it measures better than new?
Thetubeguy1954
~Rational Subjectivism. It's An Acquired Taste!~
A pegged upscale meter on even the highest range is telling you that something is wrong. The roll chart should tell you what range to use for each tube. It's possible for a tube to be strong enough to push the meter to full scale on the appropriate range, but not way over. Either the tube is bad, your tester is not working correctly or you have a setting that is wrong.
Hollow I appreciate your response but I think you might be wrong or else I didn't explain correctly. The person who's tester it is taught me how to use it. I have setting for different tubes types which I follow very carefully and I do a "line test" before each tube I test. Very, Very few tubes "pegged" the meter and those that did all worked and sounded wonderful! Most of the tubes ---{I was testing a lot of older Siemans, Mullards, Amperex Orange Globe & Bugle Boys}--- either tested in the bad range or somewhere between:
- 1500-3000
- 3000-6000
- 7000-15000
depending on which scale I should use, on the good range. So I'm fairly sure I was doing the testing correctly. Look at the question like this "if" a NOS, Siemans, 7308 tested at 14,500 on the 7000-15,000 scale. What is that specifically telling me about that tube?
Thetubeguy1954
~Rational Subjectivism. It's An Acquired Taste!~
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I'm a little unclear about your question, but I have a 600a that I use regularly, and may be able to add something here.
The 600a has two basic modes of operation: The first is a basic screening test, a go/no go or good/bad test. To use this (rough) test, you set the english dial to whatever setting the tube roll chart says, and hope the needle ends up in the green zone when you push P4. Disregard the micro-mo/numerical scale when using this mode.
The other, more detailed test is reading mutual conductance. To do that, you look at the value at the far right on the tube chart (on the 600a this is the typical value of a NEW tube), and depending on what that value is, you set the english dial at one of the three red dots corresponding to that range (3000, 6000, 15000). Then read the micro-mo scale when you push P4. Disregard the good/bad scale in this mode.
If the tubes you are testing are all pegging the meter when set on the proper micro-mo scale, the tester is likely out of calibration. Here is a link for calibrating the 600a tester:
http://www.radiolaguy.com/PDF_Files/Hickok600-600Acalibration.pdf
Calibrating can be a little involved depending on what needs to be adjusted.
The 600a has two basic modes of operation: The first is a basic screening test, a go/no go or good/bad test. To use this (rough) test, you set the english dial to whatever setting the tube roll chart says, and hope the needle ends up in the green zone when you push P4. Disregard the micro-mo/numerical scale when using this mode.
The other, more detailed test is reading mutual conductance. To do that, you look at the value at the far right on the tube chart (on the 600a this is the typical value of a NEW tube), and depending on what that value is, you set the english dial at one of the three red dots corresponding to that range (3000, 6000, 15000). Then read the micro-mo scale when you push P4. Disregard the good/bad scale in this mode.
If the tubes you are testing are all pegging the meter when set on the proper micro-mo scale, the tester is likely out of calibration. Here is a link for calibrating the 600a tester:
http://www.radiolaguy.com/PDF_Files/Hickok600-600Acalibration.pdf
Calibrating can be a little involved depending on what needs to be adjusted.
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Thank you, thank you, thank you! That's exactly what I was attempting to find out!
Thetubeguy1954
Agreed. Calibration may not be for the faint of heart, and if you screw up the bias pot when attempting to adjust, it's not replaceable unless you have another Hickok organ donor.
Well guys as I told HollowState previously I have setting for different tubes types which I follow very carefully and I do a "line test" before each tube I test. Very, Very few tubes "pegged" the meter and those that did all worked and sounded wonderful! Most of the tubes My problem was I didn't understand how people on Audiogon were saying something like I tested a tube on a Hickok 600A and the tested as:
100%= 15mA Mutual Conductance
1 Pair Telefunken CCA
Mutual Conductance;
1.15.5/15.0
2.15.0/15.5
I couldn't understand where they got that info! I'm testing a 6DJ8/6922 at these settings:
E V 7 6 0 8 0 @ 6.3V for triode 1
E V 2 1 0 3 0 @ 6.3V for triode 2
When I pressed P4 and the needle ends up in the green zone at say 14,500 on the 7000 - 15000. I didn't see the correlation between what I was reading and what they were saying. I know understand that's because I had only learned to do part of the test.
Thanks!
Thetubeguy1954
100%= 15mA Mutual Conductance
1 Pair Telefunken CCA
Mutual Conductance;
1.15.5/15.0
2.15.0/15.5
I couldn't understand where they got that info! I'm testing a 6DJ8/6922 at these settings:
E V 7 6 0 8 0 @ 6.3V for triode 1
E V 2 1 0 3 0 @ 6.3V for triode 2
When I pressed P4 and the needle ends up in the green zone at say 14,500 on the 7000 - 15000. I didn't see the correlation between what I was reading and what they were saying. I know understand that's because I had only learned to do part of the test.
Thanks!
Thetubeguy1954
If it only happens with 6dj8s I have read it´s due to oscillation. Newer models had ferrite beads to avoid it.
Regards.
Regards.
I appreciate this message very much. I have just purchased a Hickok 200a and I am a bit confused about the first (easy) way of checking tubes. I understand placing the English dial on the setting mention on the wheel for the tube being checked, but what do I do about all the other settings. Thanks in advance for any help that might be provided.
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