I just completed my build, and when going through resistance tests, with course and fine controls all the way at 0db, I measure 19.7K ohm at terminal 1 and 5. However, the manual says I should read 39.7K ohm on each, so there is a big discrepancy.
All other terminals read 0 ohm (or close to) except terminal 15 and 25 which read 205 ohm, which is in range.
Resistance at terminal 1 and 5 go down when I lower the fine tuning. At -45db I read 9.9K ohm at terminal 1 and 5. I get the same reading on the lower legs of the fine tune attenuate as I do on terminal 1 & 5. Changing the course attenuate does not change the readings on terminal 1 and 5.
I get 17K ohm on the mid post of A and C with fine tune and course at 0db. This does drop as I rotate either, with both at -45 I get 130 ohm on the mid post of A and C.
I made the assumption that this would only effect the output levels, and all the wiring looks fine, so I did proceed to the voltage tests, and everything checks out in range. I tuned the A and C tubes to 145V.
If I plug in phones, they sound a bit thinner than on my less expensive amps. They just don't have the oomph of my Schiit Lyr+.
I'm testing with a Klein MM325, and also checked with an OWON HDS272S. they vary slightly but are close enough to know I am getting accurate readings.
Thoughts? Does the resistance difference change the impedance at the output jack, causing the audio to sound thin? I am using balanced out, low impedance setting into Hifiman HE1000 stealth cans. I tested audio very briefly, in case something is very wrong -- didn't want to hurt the headphones -- so the tubes have not burned in for more than a minute or two.
I understand the Lyr+ puts out a lot more power, but I did volume match it to compare. Is it just the power difference that makes the mainline seem thin, or is the resistance discrepancy indicative of an issue somewhere?
