I measured the primary and see:
128 ohms end to end
57 ohms B+ to screen tap
71 ohms screen tap to plate end
... tom
OK, now how about the primary's inductance - if one doesn't have an LCR bridge handy
I posted this over at Edcor's forum, and I'll share it here, as well:
(
Someone was inquiring as to the primary inductance of the XSE15-8-5K, and received a somewhat "evasive" reply)
You can calculate a rough primary inductance "guesstimate" with this simple formula, which is based on the old standard calculation for inductive reactance.
Z = 2*pi*F*L (F in Hz, use your lowest frequency; L in Henries).
Turning that around,
L = Z / (2*pi*F) in order to keep the math simple. I'll call pi as being 3.14 - we don't need to go out to the 99th significant digit for this application
in the case of the XSE15-8-5K, this would be:
L = 5000 / (6.28 * 70) or in round numbers, 5000 / 440 =
11.36H for a minimum value.(
70 Hz)
For the GXSE-15-8 this would work out to 5000 / 251 =
19.9 H minimum. (
40 Hz)
If you have SE-CAD from John Broskie, you can plug these numbers into the Transformer listing.
IIRC, the DCR of the XSE15 primary is around 128 ohms, and the secondary is around 0.5 ohms.
Actual measured inductance values may be somewhat different, and they will change as the DC current in the primary winding is increased.
I have some XSE15-8-5Ks,, GXSE15-8-5Ks and GSXE10-8-5Ks on order, and I can do some actual test measurements on them after they arrive.
/ed B
Old school method of calculating Pi with only a cheap or vintage "four banger" calculator: Just remember the number sequence
11 33 55, and then
divide 355 by 113, and it comes out to Pi out to the 7th or 8th decimal point.
355/113 = 3.1415929 on a cheapo 8-digit calculator ;D
/ed B