08-26-2014, 06:27 AM
There is a good article on blocking distortion--along with the use of grid stoppers and other means of mitigating blocking distortion--on the Aiken amps site for reference. Posting it here for anyone further interested in this topic, even if it's turns out it's not the OP's main issue:
http://www.aikenamps.com/index.php/what-...distortion
http://www.aikenamps.com/index.php/what-...distortion