Audio Research SP-11 MK2 ...

I've worked on both the SP-11 and the SP-10 extensively. The SP-11 is probably a bit quieter in the phono stage then the SP-10. Both are marvelous preamps. Both bench test very well. Before comparing a new preamp with a rather old preamp one would have to recap the old preamp. That way you are comparing apples to apples. After 15-20 yrs, both preamps should be recapped before any serious listening comparisons take place.

The SP-10 was the last full-on tube preamp ARC made and was the zenith
of its 'old' sound. I owned one for many years, and its phono section was
glorious for the time period. A good clean example that has been brought
up to spec is probably fine, but it will be noisy as a phono preamp. I had a
devil of a time, back in the day, finding tubes that were not microphonic.
It was, and still is, a classic, much like the original SP 3 (which I also
owned, way back in the day). By today's standards, both are old school and
the SP3 would probably be considered very colored (it's been a long time
since I heard one), but in its time, it was a revelation, compared to
everything else.
But... since you asked about the SP-11, at the time, lot's of folks upgraded
from the 10 to the 11. The 11 was probably far quieter, but lacked the
warmth and rounded 'old school' tube sound of the 10. I think that this
actually stimulated the market for the SP-10 (at least the mkii, I never heard
a mk i). The 10 is a classic, in large part because of the sound it
represented. ARC seemed to go for a more modern, less 'tubular' sound
after that. Interestingly, the 'Ref' level stuff that ARC makes, in the form of
separate line stage and phono stages, seems to have gone back to tube
rectification and/or regulation. I just took a quick look on the ARC site, and
the preamps with integral phono stages all seem to be hybrids, following in
the path of the
SP-11, rather than the 10.
A low output MC would be a beeyoch on the SP-10. (Believe me, I tried
and
when I finally switched to horns, I had to get rid of it, it was just too noisy).
But, with low efficiency speakers and a higher output cartridge, my money
would probably be on the 10 (and i think they command a premium
compared to the 11, although I'm guessing- haven't looked at market prices
for these in a long while).

I agree with Hifigeek1. I have been using SP-11MK2 for a few years now. I bought it here from the original owner, who re-tubed it about 10 years ago. I thought it sounded great.

Then, about a year ago, I started hearing the signs of a frying resistor in one channel. I took it in to the shop where they fixed the issue, replaced a few other things that were drifting out of spec, and replaced all the old power caps.

I then retubed it with the new Genelics that just came out recently. Holy cow! What a difference! I should also note that the repairman was amazed at how quiet the phono stage was.

Will it compete with a new $20K preamp? Probably not. However, I've had notable HiFi shop owners talk me out of replacing it with something that was $8K. He also mentioned that it would be a waste of money to spend $2500 on a stand alone phono stage. (I found a great dealer ;-)

Anyway, just my 2 cents. I'm sticking with the Sp-11 now that it's been rebuilt a bit.

Bassphil..I know. I've recapped and re-tubed quite a few of those. Amazing isn't it??? lol

Can't remember what tube is used for the 11, but i started experimenting with the NOS tele in other gear, and it made a dramatic difference compared to other highly regarded tubes, holographic, without sounding too euphonic.