Low output volume from powered sub woofer

Hi all , I have a SVS-PC13 u tube sub with a Bash amp , it powers on fine and works with the test tone but at a very low volume output , (It has been working fine)

I have tested the processor output with another active sub and that seem to work fine ..

I have taken the plate amp out and tested the dc output , it is only 10.5 Vdc , does this sound low ? and would that cause the low output .

Here is a photo of the dc supply

https://www.dropbox.com/s/vmqf5e902pw7b1...