[R-390] Receiver noise

[dog]

When I don't have an antenna on the balanced (or unbalanced) inputs, the 
noise level is quite low on the RX. Using a small SS amp off the diode 
load to a speaker. Attaching an 80M dipole to the balanced port results 
in a huge amount of noise/signal increasing the output by a lot. Now on 
any of my other radios, I can hear the rx internal noise with no 
antenna, and when I attach an antenna, I hear an increase but nothing 
like the R390A. Is this typical? I don't remember these receivers being 
that much different than any others or am I having some issues with this 
radio? AGC works fine, signals sound fine AM mode in 8 or 16KBW if it's 
30dB on the carrier meter or better. Sensitivity measures less than 2uV 
and passes the 10:1 S/N tests easily with a calibrated Moto 2005D. With 
no antenna attached I can get an increase in internal noise using the 
Ant Trim but attaching a dipole and listening to 10MHz WWV I really have 
to turn the volume down.