2. amps-preamps
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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
jea48
4,528 posts
 
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?



newbee
4,777 posts
 
FWIW, Some European sourced small tubes do flash on turn-on. Not at all unusual and it is not significant. I suspect, as others, that your problem may be speaker location (set up in your room) combined with the basic difference in the sound of your new electronic’s. Audio Research components are not known for warmth and unless your system and speakers set up are synergistic and properly set up they can sound cold and clinical, much as you describe, especially compared to your old Mac. I’m an old ARC advocate but I dropped out of that line some years ago for just that reason. It is also possible that your ARC amp is just not one that works well with your KEF’s.

Take a break from your assumption that your components are faulty and that someone has lied to you. Think more about speaker set up and trying to get them (and your listening position) to sound better by properly locating them in your room, Do some research on set up. If you think you need help with that issue, just ask. Many folks here would be happy to help.

Good luck.
kentrent OP
71 posts
 
I called ARC and asked them about the tube flashing/sparking and they said that’s not normal.  

As for the set up, i placed the speakers about 7-8 ft apart in a 18ft x 20ft room.  

Same set up, I switched out the arc and use the mac1500 and has a lot of bass response especially low.   Switched back to arc and it has about 60% decreased in bass.   All speakers wires are all properly connected.   Can someone here explain this?
kalali's avatar
kalali
1,977 posts
 
If you’re hearing 60% more bass by only switching the amps, then the issue is not speaker/room set up. Assuming the tubes are fine, I would suggest trying to borrow a preamp or an amp from someone and try to isolate the bottleneck systemically. Interconnects, power cords, or speaker cables can affect bass quality but not anywhere close to +/- 60%, in my experience.
Keep at it and good luck.
big_greg
6,674 posts
 
It sounds like you're at a point where it needs to go in to a repair shop for a diagnosis.  If there's that much difference in sound quality and you've tried all the obvious things, it's time to get it looked at.
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