Channel imbalance [resolved]

[ryanred]

Just finished my Crack, everything seems to be within spec but there is an imbalance between the channels. Here are my voltage measurements, A6 and B1 are quite low.

Terminal  Spec      Measured
1              75-90    76.7
2              170        173.8
3              0            0
4              170        173.8
5              75-90      84.8
6              0            0
7              100        101.3
8              0            0
9              100          106.7
10            0            0
11            0            0
12            0            0
13            170        173.5
14            0            0
15            185        194.5
20            0            0
21            206        215.7
               
A1            90          84.7
A2            0            0
A4            0            0
A5            0            0
A6            90          77.2
A7            0            0
A9            0            0
               
B1            90          76.8
B2            170        173.7
B3            100        101.1
B4            90          84.9
B5            170        173.7
B6            100        106.4
B7            0            0
B8            0            0

After that, I followed Caucasian Blackplate's suggestions in this thread http://bottlehead.com/smf/index.php?topic=7788.15.

Terminal              Measurements
RCA jacks            772mV    772mV
Pot Center Lugs    772mV    772mV
A2 and A7            772mV    772mV
Headphone Jack    5.692V    6.78V
Term1, Term5      8.9V      10.4V
Term6, Term10    4.81V    5.834V

Do I need new tubes, or does something else appear to be wrong?

 

[fullheadofnothing]

The difference in voltage from the manual value is caused by a strong tube. It is nothing to worry about.

The channel imbalance you measure is just over a dB. Most people cannot reliably distinguish a difference that small. It is more likely that you have a potentiometer that isn't perfectly matched at low levels. Install the padding resistors to resolve this, or you could turn down the output of your source which would require you to turn up  the potentiometer on the Crack.