Voltage halved at terminals 7 and 9

[wieders]

I've ran through the instructions on including the speedball.  All voltages check out except terminals 7 and 9 are coming in at about 55 v rather than the expected 100.  Plugging in the amp and putting some music through resulted in a lot of low frequency hum if I turned the volume up.

Has anyone encountered this issue that could lead me down the right path here?

 

[fullheadofnothing]

Can you please clarify: is the Speedball in or not? If the Speedball is in, did the Crack work properly before it was installed?

Voltages this far off are a clear indicator that your amplifier is not working. Do not attempt to use an amplifier that is not working; doing so may damage your headphones.

 

[wieders]

The speedball is in.  The crack worked properly before I installed the speedball.

 

[fullheadofnothing]

Post pictures.

 

[Paul Birkeland]

What voltage do you have at B+ on the big PC board?

I agree with Josh, photos will help.  Trying to use an amplifier that does not pass its voltage checks will not.

-PB