So...I happened upon a cigar box of tubes in my dad's house and much to my surprise I found what looks like a set of new EL34 and 7199 tubes. From his collection I also have an EICO 667 tube checker with manuals. I would like to put the tubes on the checker to assess their condition but I have no way of verifying that the checker is giving me usable results. I did the calibration procedure in the manual and it seems like the whole system depends on the line voltage for it's accuracy. The schematic shows very little in the way of caps or other age sensitive parts. Is there a way to make some sort of "standard" tube to use to check the 667? What is your experience with these old tube checkers? What do you recommend? Should I mail them to someone with a known good checker and compare my results? Thanks a bunch for your expertise! Rick
3 posters
Checking my tube checker!
n3ikq- Posts : 26
Join date : 2014-10-16
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
Just leave the tubes in their cigar box until you have a ST-70 or similar amp to use then in.
Playing with an unknown "tube tester" might even destroy the tubes, not to mention that
the result of the tester won't tell anything about the tubes ( if they are noicy, if they will
keep stable bias etc). Use the tubes or sell them "as is"
Playing with an unknown "tube tester" might even destroy the tubes, not to mention that
the result of the tester won't tell anything about the tubes ( if they are noicy, if they will
keep stable bias etc). Use the tubes or sell them "as is"
n3ikq- Posts : 26
Join date : 2014-10-16
I should mention that I did check the original tubes that I am re-using in my rebuilt ST-70 with the EICO so I know it works. I just don't know if the readings are accurate having nothing to compare them with or no standard calibration jig.
n3ikq- Posts : 26
Join date : 2014-10-16
After some digging around I did stumble upon a document that went into some detail on the Eico 666 and 667. I'm fairly convinced that my unit is working about as well as it can and when calibrated should give reliable readings. I will give the url for anyone who may have an old Eico 667. I also welcome any comments on the tube checkers or checking tubes in general since my electronics hobbies came in just as tubes were going away!
http://www.fourwater.com/files/restr666.txt
http://www.fourwater.com/files/restr666.txt
Tube Nube- Posts : 707
Join date : 2008-12-06
Age : 61
Location : Calgary, AB
It's getting to the point where it would be nice to have my own tube tester!
It's Richard isn't it? If not, I made a faulty assumption from your moniker. If so, I'll add nice pic of you with your "second order harmonic" on QRZ.
It's Richard isn't it? If not, I made a faulty assumption from your moniker. If so, I'll add nice pic of you with your "second order harmonic" on QRZ.