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
Guys!! Seems like my bass response problem solved. I installed an EQ and this boost the signal tremendously which now i can do tone control. This is my current set up and it now sounds amazing like it should. Fuller sound with deep bass response and clear treble with details.

CD to EQ to LS15 to VT100 out at 4ohms to R900.

(From preamp to amp using XLR and the rest are RCA interconnect)

Although i solved the bass response problem but I’m not satisfied with the sound completely since the EQ makes the sounds too artificial (even though it sounds very good). I want to be natural sounding as much as possible. Perhaps i should look into a preamp that has tone control? Or i should get a good DAC to boost the signal into the preamp? Any recommendations?

thank you again for being so helpful and wonderful. Love this community. 👍👍
@lowrider57 tube V3 in LS15 still sparking when turned on but with the EQ added the sounds boost to an amazing level.  :))
But I’m still replacing the v3 tube just to be cautious since ARC said that’s not normal. 
The EQ is a good temporary fix. Please keep an eye on the preamp for any shorting out or shutting down due to the tube.
:-)