Hi Murray,
Thank you for your response. If you can, could you answer a couple of other questions? Did the 9-66AU also lower the grid signal from ~5.0 Volts AC to 2.5 Volts AC? I have only been able to find info on the 9-66 on the internet. Do you know of any links that discuss the differences between the models in any greater detail?
Thank you in advance,
Jon