Primaluna Integrated with a seperate preamp

The updated versions of The Prologue and Dialogue Premium with an HT input has a true pass-through that eliminates the preamp section. Here is the description in the latest owner's manual:

Stereo Home Theater Pass Thru  
The PrimaLuna DiaLogue Premium Integrated Amplifier is equipped with a home theater pass thru that allows you to enjoy your stereo source material and the 2 main channels of your separate home theater processor. This is a true pass-thru circuit. Most integrated amps that advertise having home theater pass thru circuits are only “unity gain” circuits. This means the volume is set at a pre-determined level, but the preamp section is still active and can introduce unwanted noise and coloration to the sound. The home theater pass thru of the DiaLogue Premium HP Integrated Amplifier completely removes the preamp section from the signal path. This is a “direct-line” circuit that results in a lower noise floor, and less coloration.

The only issue I find with the HT input is that it is the only input with tube hum / noise. With or without anything connected to the HT input. All other inputs utilizing the preamp section are dead quiet. I tried grounding and cheating the ground of the amplifier but no effect. Is the tube hum / noise due to the fact that the HT input goes directly to the power section / tubes? 

Saki70-
I have the PL Dialogue HP integrated.

Earlier this year, I picked up a used Dialogue Premium preamp, with intentions of getting 2 HP amps.

Used the pre with the integrated thru the HT. The sonic difference is quite subtle, I couldn't hear it. Maybe its a YMMV thing?I just know my wallet was saved from further damage, because I changed my mind about going separate line stage/amps.

I do use the HT bypass with my Mac MR71 tuner.

I never found this thread as I asked the same question Saki did.   I borrowed a buddies ARC LS26 and hooked it up through the HT bypass and was disappointed.  It sounded great with his ss amp but completed different with the PL.  I also called Kevin @  Upscale and he said why would you want to add a preamp.  After listening to the LS26 with my buddies ss amp i knew there were a few things missing with the passive preamp section of the PL.  However,  it didn't match well with the PL. The PL sounds very good regardless but there's something to be said for a good preamp. 

tablejockey & samzx12 ;

Thank you for your input . Nothing like real world experience .

@1graber2 I replaced the stock 12AU7 tubes on my Dialogue Premium integrated amp with Cifte 12AU7 as recommended by Upscale Audio. These tubes added more texture and a more holographic sound. I also tried other NOS tubes that are all better sounding than the stock tubes. I also replaced the stock power tubes. I suggest you call Upscale so they can help with deciding which tubes may help your needs.