Audio Research LS series......

I am thinking about adding a tube preamp to my system. I use a highly modified Accuphase C200 right now and I am happy with it. I would like to have a tube preamp that I can the top price would be about $1500 used. I was thinking about changing the coupling caps with some V-caps(or other). My goal is to have a very natural,transparent sound,and a very good soundstage...the pre would be warmer but not compliment my SS C200 preamp. I have read reveiws on the LS2,LS15,& the LS17...any thoughts. I use RCA connections and need 2 sets of outputs. My equipment is...

VAC 140's
NBS cables
custom dynaudio speakers

Thanks for any input...

P.S. I know there are many tube pre's that I could use...but I think that for the money I want to spend the ARC would be a good choice.
Pardon my ignorance on the LS series...Some are SS I guess...I would only be interested in the tube type.

My recommendation would depend on how much $$ you want to spend. I have owned the LS2B, LS2B mkII and the LS25 MKI. The LS25 MKI is a very good performer, but will be quite a bit more expensive than the LS2B. I have tried the LS15 in my system and it is a fine linestage. I have not used the LS17, but it has a very good reputation. The LS25 is the best of the lot that I listed above.
Get an LS 6C for about $700, spend another $500 having it upgraded with new RCA's and power cord, new tubes...and you will have a simply amazing pre.
ARC never made a LS6C. This would be a SP6C and was a wonderful preamp in it's day. I would recommend also the LS2 version (try to find a LS2BMKIIR).
Martin Colloms has tested most of these in various magazines and rates them as follows: LS15, 25 points, LS2, 25 points, LS22, 30 points, LS3b, 25 points LS7 28 points. For comparison he gives the SP10 11 points. See the HIFICRITIC web site for explanation of rating system and other ratings.
I own the LS-2. Great amp, responds well to tube-rolling and should be available for much less than your budget.
The LS-2 cannot be considered a tube preamp as it only has one tube. It is considered more of a hybrid. It does however sound very good particularly the mkII version. The LS-15 is also a good performer and can be made better with a good quad of Nos tubes. But the LS-22 will give you more of a tube sound as it has eight tubes and is the best of the three. Sometimes they can be found here on the Gon for around $1500-$1700 but not very often.
Thanks for all the responses. I came across a website SACDmods that does upgrades on ARC....anybody have experience with them? The LS22 looks to be a good upgrade....I will explore further.
Great Northern Sound Company is also another good choice for ARC mods. The guy used to work at ARC for something like 20 years. I've gone through LS-1, LS-3, LS-2B Mk II, and now LS-25 Mk I w/ GNSC Ref mod.

I've rolled many tubes in my LS-2B, but the LS-25 was a big improvement over the LS-2B Mk II. As I've not heard a stock LS-25, I am not sure how much of the difference should be attributed to the mod.

I had also done a side-by-side comparsion of my LS-25 with the Ref 2 Mk II. Per the judging "panel", the difference was fairly small between the two. At that time, I had a quad of Siemens 6922s in the LS-25. They are not my favorite tubes in ARC gears. I later swapped them out for some Amperex 7308s and also tried some Amperex 6DJ8s. I think with the swap of tubes, the modded LS-25 could stand shoulder to shoulder against the Ref 2 Mk II.

One thing about mods is that you will never recoup the cost. I had purchased mine from a dealer. The previous owner had done the mod, and decided to trade it in for something else in less than a year (Found that out talking to GNSC). Had I purchased a used stock LS-25 at that time, and send it in to get it modded, I would be spending just about the same amount as buying a used Ref 2 Mk II.

I wouldn't consider an LS2B one of the "tube" ARC preamps (though it has one). It sounds (sounded) to me more like a hybrid or SS preamp.

If you have to stick with ARC, I'd go for the LS25.