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
Did you receive owners manuals with your purchase?  If not, you can find them on-line.  They should help explain the XLR jumpers.  They are little "U" shaped pieces of metal that the seller should have provided.  Make sure you place them in the way ARC indicates.  
@alphaguy65
The Op is using balanced cables from preamp to amp. Maybe he should try RCA unbalanced.

I've also listened to the R900's with only 30W; very large cabinets with deep bass, huge soundstage.

@kentrent  Something we haven't discussed is your speaker setup and your room.

((And tonight I discovered the LS15 one of the tube (V3) has white sparks when i turn on.)))Some tubes flash upon turn on which is normal. Make sure you're on the 4-ohm taps and your speaker wires are in phaseand speakers not too far out into the room.
@audioconnection the tube flashing and sparking is normal? Also speakers are rated at 8ohms though 
kentrent OP31 posts

08-29-2019
8:42am

@audioconnection the tube flashing and sparking is normal?

In your case, imo, no


kentrent OP31 posts

08-28-2019
10:14pm

So as i was doing all these troubleshooting the LS15 keeps shutting off randomly every few minutes. This prob new since i got it yesterday. What is this guys? Im beginning to worry... :((


The preamp protection circuit was/is shutting down the unit.I would not power up the preamp again until you install the new tubes. Hopefully the bad tube didn’t take out a resistor.

As for why the 6922 tube shorted, went bad? I have had new 6922 short after just a few hours of use. It happens.

Just curious approximately how many times have you turned on, and turned off, the preamp since you brought it home. Repeated power up can cause stress on a tube.

Did you read the owners manual for the preamp?