Primaluna Integrated with a seperate preamp

As Tomcy6 suggested , I did contact Upscale Audio and asked them about the 'unity gain' circuit situation . I will post their reply here , but first a word . I am doing this for future reference to anyone also wishing to know , and reads this thread in their search for an answer .
Please , to all who have contributed here , I do not wish you to have any bad feelings or remorse . So please don't feel slighted or think that I am ungrateful for your helpful contributions .
With that said here is their answer...

"The HT input does not remove the integrated’s gainstage from the signal path. It sets to unity gain and defeats the potentiometer, but the gainstage is still in the signal path. The only real reason to use an external preamp is if it is a home theater processor/receiver and you want to integrate your two-channel and multi-channel systems.
Using just a standard two channel preamp won’t give you any meaningful performance gains, unless you are looking to use a significantly better preamp than the one built into the integrated. At that budget, honestly that would be a step sideways at best. At worst, it really would only serve to add another piece of gear where noise or ground loops can be introduced."

The budget that I used was $1,000 for a used preamp .

Again many thanks to all of you that contributed to this thread .

Happy Tunes

Interesting Saki70, since the PL site/manual itself says that it does not only NOT use unity gain, but states it is inferior. Now, the response above that was quoted from Upscale states it DOES use unit gain. 
Weird.
Clarification?
thanks, Gary

Yes . I used a Prologue Premium pre-amp into a Prologue Premium integrated while saving for Prologue Premium mono-blocks. 

Ive had my HP Integrated about 4-5 months how.
On my speakers, Dali Helicon 400 v1, 88dB, 4 Ohm, the Ultralinear and especially the Triode sound thin, dry, poor soundstage- mostly just left and right, not L/R/Ctr, front, rear soundstage. 

So this was my question: Is this due to the preAmp 12AU7 tubes?
Or the stock PL EL34s?

So I hooked up my Eastern Electric BBA/Booster Buffer Amp (a tubed preAmp with a Volume knob and Gain knob only) as a PreAmp into the HT bypass of the HP Integrated. Now, we are in business.

Like night and day. Suddenly I have texture, nuance, power, soundstage galore. Exactly what I am looking for. 

So I will contact Kevin @ Upscale Audio to ask him about this situation, and I may need to replace some of the stock PL 12AU7s. Or perhaps there is a defect? 

Any suggestions?

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?