Audio Research VT100 MK1 and LS15 HELP!!!


I recently bought this set VT100MK1 and preamp LS15 and while I was at this seller house he demonstrated the sound from his online Tidal on TV connect optical to the DAC Luxman DA - 06 then this go to the preamp LS15 and out into the VT100. This set up sounds amazing at his house. However, when I came home play CD from the Sony X1100ES Blu-ray player RCA output into the LS15 and out to the VT100 and it sound horrible - no bass at all in any type of music.  The sound sometime muffle and not clear and most importantly the bass missing tremendously. Im using a pair of KEF R900 Speakers. What is wrong here? can anyone help me correct the sounds? it is because I didn’t have the Luxman DA - 06 DAC? or it is because I don’t have those fancy hundred - thousands of dollars cable?  or the CD source is playin at 41khz /16 bit not high enough signal?  

This is my first system and I don’t know why I can’t get that high fidelity sound from the ARC equipments.  I'm waiting for the Audioengine B1 to arrive so I can stream Spotify into the LS15.   What is wrong with my set up?  Thank you in advance for helping me solve this.
kentrent
Do you have any other sources? TV, turntable, tuner. 
Maybe the Mac 1500 has a preamp output you can plug into the amp.
@lowrider57 i will try different source today to see if the sound changes.  Maybe ill use another bluray player 
But i cant explain why my arc setup is low bass response.  I’m kinda sad and disappointed that i spend a lot of money but im not getting the sound i want.
Again- did you swap the phase on **only one loudspeaker**?
If you did both you would not find anything out. You have to swap the phase on just one.
@atmasphere im not quite understand what you’re saying... can u explain. Thanks 
kentrent OP12 posts    

08-28-2019   
 3:46pm


 At the seller house setup, he only turn on 30% and i can hear music pretty loud. But when my setup i had to crank up to about 70% to hear loud.

Are you 100% sure you have the speaker cables connected to the VT100 amp terminals correctly?
( 0 ) is common, neg ( - ). Make sure both speakers neg ( - ) is connected to ( 0 ) common on the amp.
Pos ( + ) on the 8 ohm or 4 ohm terminal on the amp.
Verify 100% you have them connected correctly.


Also make sure the interconnects are plugged in all the way.