ARC LS25 with PASS X250 - bad match? Seems bright.

I owned a VT100mkII, & it's pretty neutral sounding "for a tube amp", but still, it's unmistakably a tube amp. Why did you want a different amp?

I looked at your cables, they're on the "budget" end of Cardas cables, is that right? My experience is that the "budget" Cardas cables are not that great, you have to go to the higher end Cardas to really get the sound Cardas is known for. So I'd really put cables on the list of possible upgrades, along with the DAC, apparently.

I own an LS 25 mk1 and sometimes find that it tilts the sound a bit to the "dry" (rather than "bright", per se) side, depending on the character of the the balance of the system. Relative to my Joule preamp, for example, the ARC sounds a fair bit less tube-like thru the upper registers. If the Pass leans that way, too, it's possible that the combo could sound a bit bright/dry/analytical for some tastes.

Just one more data point for you to chew on.

Marty

Marktomaras, about the X1, the only way to know how it might interface is to try in your system. Too many variables to know otherwise--cables, speakers, room, etc, in addition to the impedence of the pre to the amp. I will say that the X1 is voiced to the cooler side of neutral, based on my own experience with it in my system. I used the X1 for about a year. It does many things very well, but I prefer the overall sound and lower gain structure of my current XP10, in my system, and IMHO. Of course, YMMV. Good luck and keep us posted.

let's first establish that brightness is the perception of excess sound pressure level in the upper midrange/lower treble.

it may be the result of subtraction in the upper bass/lower mids or a peak somewhere in the range 1000--3000 hz.

ok, what could be responsible for this. ?

i assume you did not notice this with the vt 100.

it is possible that there is an impedance mismatch between amp and pre. it could be that the ls25 has problems. it could be that the pass has problems. or, as you say, there may be something else about the pass/ ls25 combo that is creating the problem.

i would try other preamps, to see if the problem persists.

as has been suggested, there may be problems with other components, which the pass, being less "colored" than the audio research is revealing.

my experience with solid state is that there is also a speaker amp relationship which needs to be considered.

does the rockport have a metallic tweeter and where is it crossed over from midrange to tweeter ?

why did you replace the audio research with the pass ???

Some people may disagree but I think part of the problem is the X250. I had one in my system and complained that it had too much midrange and high energy. Great bass control WOW!!! I have also heard the VT100 and loved it. Night and day difference between it and the 250. The X .5 series is supposed to be much smoother than the original series from my understanding. Overall I didn't keep the X250 very long. Also I think it depends on other factors but your cabling is on the smoother side so its hiding even more of the brighter aspects of the 250. Personally I would keep the VT100 and try more neutral cabling to open things up more. You might be surprised. I had the Cross speaker cables and while they were a step up from my older cables they are not known for neutrality or openness. Cabling is very important or at least has been for me. Just my 2 cents.