Audio Research sp 11 compared to the sp 10

Am looking for an AR sp 11, but have had no luck. There's a sp 10 on ebay (plus a sp 11 that has four days left) The sp 10 is still under $1100 with time to run out tomorrow. What's the difference between the two AR pre-amps? Is the sp 11 that much better than the 10? TIA
The Sp - 10 (either 1st run or Mk II version) is a better preamp than the SP 11, which is also a very capable unit. imho the Sp 10, is followed by the Sp 15 and then perhaps the Sp11. All are wonderful performers.
I have a SP10II. wouldn't part with it - bought it around 1984 and it has been the core of my system ever since. When the SP11 II came around I found it to be brighter (some people read this as more detailed). The only problem with an SP10 is it needs quiet tubes. If the SP10 on EBAY isn't a II plan to have ARC do an upgrade - its really worth the difference. The phono stage is worth the price of admission alone. Excuse the testimonial, I just couldn't resist.
The SP-11 is hybrid tube/transistor, the superior SP-10 is all tube, and lots of 'em. Take the 10 in a New York minute.
Had a Ten got a Eleven. Simply should have kept the Ten..Tom
I have had all of the above mentioned and agree the 10 is the choice.
How does the SP10 compare to the newer stuff?
SP10 vs newer stuff: I'm not sure I would readily chose a contemporary pre over a well maintained -- perhaps tweaked -- SP10.
The sound is lush but bold and clear. It is inviting and charming with nice tonal "colours" (to my ears). Newer pre's would be perhaps more dynamic & voiced to create an illusion of more resolution in the upper register. Don't forget, however, that new designs may benefit from components that were not available in the same quality years ago (that you can upgrade in the sp10 anyway...).

Also remember, the design & workmanship on the 10 are good: IMO an SP10 would have to be compared to upmarket "newer stuff"... i.e. expensive newer stuff. Dare I say that a top-notch SP10 may even be compared to AR's own ref2, for example...but that's just my taste!
Thanks for the replies!
Both the SP-10 and SP-11 are very capable preamps. They both have different sound signature and have their equal share of strengths and weaknesses.

Both of the above preamps will sound wonderful and magical under the hand of a capable audiophile.

I believe that modern preamp design already reaching its peak during the mid/late 80's. There is no break through in preamp design after that. The major break through is only on the price of the preamp....getting more and more expensive....

I once owned a ARC Ref 1 and it was in my shelf for only 5 hrs and I sold it on Gon the next day.
I agree that any quality preamp whenever it was made will work very well. I owned a sp11 for many years and enjoyed it very much. I do feel however that todays ( high end ) electronics have the advantage of using better parts that that where not avaliable back 15 years ago. I do feel todays top preamps sound more like live music!
I have a very nice SP11 I will be listing on GON soon I would like $1700.00 please call or e-mail me,thanks Ed 810.227.8435. I think it sounds great, but I'm going to an active LINN system.
I think the newer ones are not as musical. Just my taste.
If you use the phono section the SP 10 & 11 are excellent

Some of the upper end Line Stages are more resolving
The LS5 MKII or MKIII or Ref 2, LS 25

If you have an SP10 and would like to hear what it is really capable of doing with the latest capacitor upgrades look into Steve Huntley of Great Northern Sounds. He worked for ARC, Wadia and Cal and my friend's preamp was a whole different animal after his mod. I'm lining up my LS 5 soon.

I have listened extensively to the SP-10 mk 2 with nos tubes in my system. I currently have a CAT SL-1 Mk 1 which is of the same vintage as the 10. Both are excellent pre-amps and were compared in a mid 80's Stereophile along with the SP-11 by Anthony Cordesman. I always preferred the 10 over the 11, just a preference in presentation.

There is something quite magical in the midrange with the 10, great bloom and stage depth that is hard to resist. With an upgrade of better parts from Steve Huntley (I spoke with him a while back and he was using a highly modded 10 as his reference) you can't go wrong. One area it definitely separates itself from the CAT is the phono stage which is just as good as everyone above notes and the CAT is no slouch in this area. I would definitely consider the 10. Also of note is that tubes are critical for this pre.
btw Dave, don't expect that 10 to stay at 1100.00 by the end of the auction. If it is a Mk 2 it will end upwards of 2K most likely. A very desirable piece it is.