ARC LS1, LS2, LS3 , or LS7, which to buy?

Oh great and knowing Audio Research mavens, I have around $750.00 to spend on an ARC preamp. The models listed above are all in my price range. Can anyone sort out the sonic characteristics a bit for me, I have no way of auditioning any of these. Balanced outputs are not required. This is the start of a new system, so info on solid state power amps that have a synergy with the ARC preamps would be appreciated as well. Thanks, Marty.
Hi Marty - I think we all have a more clear view into your budget....looks like the $500-700 range? The ARC pieces in this range are at two extremes: warmth and dimensional but lacking detail that I sense you are after, and the other end which is very analytical and flat. You know the CJ sound of this same time period and that has not worked. What about some of the older Classe or McCormack models? These units were consistently rated as a sound somewhat in the middle. And I have to believe many are in your price range.
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If you are looking for a vacuume tube sound your not going to find it in the LS preamps u mentioned, since they are hybrid designs. I used to own a SP-6B and liked it alot, although working on it is a rather big chore. The 6B has a lumpy frequency response. If you could find an 8B that would be better or a used SP-3 and get it updated when u have more money to spend to a 3C. That has to be sent back to ARC but they totally replace the power supply, tube sockets, coupling caps and volume control as the stock control was a noisy sucker. In this preamp u have defeatable tone controls, a nice feature. It might even drive a high output moving coil, or find a used step up device. BTW Im not a big fan of the SP-9/SP-14 unless their upgraded but they are still hybrids. G.Garfield
I would refer to the LS-2 as the best solid state preamp ARC has made, even though it sports 2 vacume tubes. The line stage is quite a bit more accurate than my SP-8 or SP-10. If a head to head shootout were done on the direct input of the LS-2 versus the line of the SP-10,11, 8, 6 or SP-3,most would find this to be the case. Amazingly, the SP-3A-1 Line stage section is quite a bit more transparent than the 6, 8 or 10 in any iteration.(but coloration is too high) Do I find the LS-2 to be sonically delightful? No,not enough to recommend it.......But, it will more than hold its own against many units at the used asking price. Link it with a D90B series or before 1983 ARC tube amp for best results.
Regarding ARC, I can't remember myself thrilled with any offerings; as John (jafox) I had singled out sp10. The 9 wasn't bad -- but I believe this opinion was linked to its much more reasonable asking price rather than performance...

Not intent on steering you away from ARC, I nevertheless remember comparing a sp10 with that an old mark lev pre at s/one's house. The ML was much better in dynamic presentation and frequency extremes (esp upper). Please note: I "remember".
I CAN'T remember if it was the ML1 or ML7 (probably the latter). I'd expect prices to be similar were you ever to consider such a machine (OTOH, mark lev used different connectors which means you'll have to solder a bit).