[jake wells]

Have two NOS tubes one is a US NAVY 5Y3 and the other is a ken rad 5Y3. The radio works fine with either but is this a common issue for these types of tubes? Let me know what you fellas think.
US NAVY 
Audio B+ 280
Rect B+ over 300 my meter only goes to 300
Rf, if, det, B+ 201
-------------------------------------
Ken rad
Audio B+ 249
Rect B+ 302
Rf, if, det, B+ 179

[tbone]

Recently I’ve tested and swapped tubes in a few radios to get the best performance, or at least the theory that my radio is working better. I’ve measured AVC and Power Supply voltages too.

I’ve seen certain brands like National Union NIB and the like test not as good as some major brands. I think the way tubes were mass produced, they had minimum specs to meet, and if they did, out they went for sale. Military tubes are supposed to be built to better standards, so it’s possible that they can test better.

The bottom line, unless it’s a high end amplifier that needs matched pairs, most tubes are fine. Most radios will never notice the difference, even with a weak tube. You’d be surprised how good a radio with weak 45’s can still sound.

[35Z5]

What does schematic give for B+ reading?

US Navy mfg'd by?

May be a 5Y3/6087?

[jake wells]

says C.H.S. on the navy tube.

[35Z5]

CHS should be Chatham, basically Tung-Sol's division that produced mil spec and other speciality tubes.

Without knowing voltage specs, no clue if one is high or other is low. Not uncommon for B+ to vary 5-10v on different new tubes but 30v is excessive.