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
@almarg, the random shutdown is resolved for now.  But about the jumper, i dont have anh jumpers connected to the xlr. 
Would it damage the system if i dont have jumper connected while using rca?
Damage, no.  Read the owners manual why the jumpers should be installed when using RCA single ended ICs.

Didn't the seller give you the jumpers for the amp? Surely he mentioned them.
Would it damage the system if i dont have jumper connected while using rca?
No.  It just wouldn't be sonically optimal, and it might result in a bit of hiss and/or hum.  

Regards,
-- Al


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