HT bypass (when available) will allow an integrated amplifier to behave as a power amp, and the preamp (or HT receiver) will connect to one of the L/R inputs on the integrated amp.
I couldn't find the owner's manual for the OP's model on-line, so not sure if it has this option.
Some brands/models allow every input to be used for this feature, and some designate one particular input for this. For some brands/models, it is enabled with a switch on the back of the unit (Naim). Others may enable automatically on just one input, while others will allow any input to be set for HT bypass (software controlled on the amp).
@atorres53, do you see anything in the owner's manual regarding HT or Home Theater Bypass? I don't know how common this is for tube integrated amps.