Question on Bassman AB165

[JammyDodger]

Hey All,

I just picked up a '66 Bassman. I opened it up to look at the circuit and found that the bias had already been changed over, so far so good. Then I started looking into the feedback loop. This has been modified as well. There is the 820 Ohm resistor except it is not connected to the OT it is open on one side! There is a 270k Resistor where the 100 Ohm should be to ground. Any reason for this?

The amp sounds 'decent' although there is room for improvement.

Any ideas why this was done?

Cheers, Mike