[Premium-Rx] Can I open the audio output of the 6790 repeatedly to mute without damage?

[Ka9p at aol.com]

Every couple of years I want to put one of the 6790's outboard of a  
transceiver but haven't found an honest to goodness mute mod.
 
Does anyone know of one, or will it survive me just breaking the audio  
output with a relay (assuming the AGC recovers) or will I need to make then  
break a load in place of the speaker to protect the output?
 
I'd guess it's robust given the rest of the design but thought it better to 
 ask than to do the experiment.
 
Thanks, Scott