[Elecraft] K3 AF Gain

[Mike via Elecraft]

I know I'm probably stupid and missing something obvious, but when I turn  
on the sub receiver it is much louder in my right ear than the main is in my 
 left with the AF gain set the same on both receivers and both VFO's tuned 
to the  same frequency. RF gain is set the same on both receivers.  I  have 
one antenna connected to ANT 1 (which then goes to KPA500 then  KAT500).  
The settings are as came from the factory and diversity is not  on.  I've 
looked through the K3 manual and Fred KE7X's book and don't find  anything. Is 
this the 3 db attenuation when signal split to both  receivers?  I would 
think the attenuation would be equal. Firmware is the  latest. Sorry for the 
bandwidth, it's probably something obvious.   Thanks.
 
Mike KD8RQE