The LS22 was produced for only a year (1995), and is therefor the least well known of the recent AR linestages. I think this the reason it is such a bargain on the used market. It is, in fact, fully balanced. It can also be used with single ended sources and amps.
Do a Mfg. search on AudioGon to get a list of all the models and dates made. Subscribe if you want pricing. It will give you a sense of how their products evolved.
steer clear of the newer ARC LS22, 25, ref1
most bang for buck LS5 MKIII
it is fully balanced inputs but you can get cheater plugs and it sounds just fine
this pre is more musical than the Ref 1
and a lot less costly
the ls5 has a luscious sound, warmth, dynamics, soundstage
really opens the music up, is revealing and is tonally balanced
you can sometimes find them for $2000-$2300
the mk ii is nice also
If you want a phono stage try the SP vintage from ARC. They are all a great value at their used price. I like the SP-8 (800-900.00) better than the SP-6A (700-850.00) both of which I owned. I can't comment on the B-E series of SP-6.
If you can find one, don't hesitate on the SP-10 Mk2 it is a great pre-amp with an excellent phono stage. You'll be lucky to find one cheap but miracles do happen. I have a friend who picked up a mint one for 1.5K, typically 2-2.5K.
I agree with Audiotomb. The best of ARC's linestages I've heard is the LS-5. I have also listened to the LS-15, LS-16 and LS-25 and they are ho-hum compared to the LS-5.
There is an issue with the turn-on on the SP-6A that I have not heard about in a long time. The SP-6B has this fixed. At turn-on there is a DC transient that gets passed through the preamp. If you have a DC coupled amplifier (solid state amp designs), you may (and I have) overextend any woofers to the point of destruction. The SP-6B has a warm-up timer which prevents this.
Sounds trivial, but it is incidious. Long time ago, I was listening to stereo, warming up for run. Went running, did not turn off system. While I was out, there was a short power outage. I came back to blown speakers. Ouch.
Anyway, lots of people still interested in SP-6, so I thought I would tell my story from 24 years ago.
Recently, I have switched to an SP-11 and I like the SP-11 better than the SP-6. But the SP-6 (not as good a soundstage) is a warm, wonderous beautiful sounding preamp. Mine has been modified with Sidereal caps. I was actually surprised at how good it was compared to the SP-11. SP-11 is the winner though, bass much better, soundstage much better.
Another feature on the SP-11 that is nice is that the phono stage is much quiter than the SP-6. This can allow one to use a lower output MC cartridge without a step-up device. SP-6 works fine with normal output levels, but I have tried a .2 microvolt cartridge and it just plain is noisy at the gain required.
My impression is in the world of SP-6, the SP-6B is the unit to have. I have owned my SP-6A since 1979 and it is still apparently worth within $100.00 of what I paid for it.
The LS-25mk1 with the right combination of NOS tubes will easily outperform a stock LS5 mK1,2,3, Ref1, LS-15,16,22 and 25mk2, not to mention the Ref2mk2. Beware the 6h30 tube. I would highly advise that you never ever under any circumstances - purchase a tube pre-amp that takes (8) 6922/6dj8 tubes. This is one of the worst tubes ever. but the 6H30 may even be worse. You will never be able to find the right combination with (8) tubes. Nos is mandatory and if you are not educated and have $$$- forget about it. Don't even think that you can get away with that Russian 6h23 tube- garbage. Four 6922/6dj8's is hard enough to deal with. I would also stear clear of the lower resolution SP series if all you need is a linestage. So if you want an ARC linestage with remote control- go for the LS-25mk1 with Amperex/Siemens NOS tube combination. If you think you can handle (8) NOS tubes- go for the LS-5mk3.
I own the LS25 MKI. With NOS 6H23 tubes (6922) it easily out performs the LS25 MKII. It is a very musical preamp. I am very satisfied with its performance compared to some very expensive preamps that I have auditioned in my system.
I went from LS-25mk1 to LS-25mk2- back to LS-25mk1. Have you tried some Amperex 6dj8's and Siemens 6922's. The 6H23 are better than the Sovtek 6922's but they are still far removed from the 1960's European tubes. But I'd still choose the 6H23 over a 6H30.
I agree with tubegroover's recommendation on the SP8 & SP10. I got an SP6C1 with the muting circuit moded. The C1 uses 12ax7 (4) and 6dj8 (2). The 6dj8 has about an 8 db better signal to noise ratio over the 12ax7. Mine is fairly quite running a low output MC. The tubes used on the preamp makes a huge difference. I did lots of tube rolling with Mullards, Telefunkens, GE, Amperex...etc.
Well, I have a ARC SP10II AND a Mesa Baron! That said, the pre-amp you pick will be determined by what tone you expect to get. The Baron is neutral and can be more like SS except for the presence of tube air and spaciousness. I like my system to err on the warm side and would not recommend an ARC amp later than the SP10II - I'd look at SP8II the SP6 (latter models) and if you want classic ARC warmth, and can give up a bit of resolution, the SP3. If you don't need a phono stage, I would suggest that you listen to an EAR 834L. They are cheap, easy to tube, and sound much like they SP10 (in fact except for the bass, which is better in the EAR, they are incredibly close). I use one in a second system. The differences in ARC pre amps has been discussed at length and accurately in the Audio Asylum forum and I would suggest you do a search there.
My two cents:
I have an LS2B mk2. Used for $750.00 on audiogon and is a terrific value. the amp is a music reference rm 200, audio aero 24/192 mk2 cd player, vpi scout tt, pass labs xono phono, audio physic virgos, nordost spm, quattro fil and silversmith cables. the LS2b offers great resolution, a big soundstage and it's noise free as well. I don't think you have to pay the LS22 or 25 dough to get the performance. good luck!
I have listened to both the SP-10 MK2 and SP-11 M2, clearly the two best vintage preamps from ARC. I find the SP-10 MK2 to sound warm and tuby, and when compared to the SP-11 MK2, it lacks the high & low end extension and sound a bit too syrupy & dense in the midrange. However, when matched with a leaner system, it could sound very inviting. The SP-11 MK2 has a cleaner, bigger, faster, more detailed and more dynamic sound. Its midrange is more neutral (just a bit tuby) and very liquid, but not emphasized like that of the SP-10 MK2. Furthermore, the SP-11 MK2 in terms of bass slam depth and speed is far more impressive. Overall, the SP-11 MK2 has a more linear sound with a blacker background.
The better preamp? I believe that it depends on what you have. If your system, independent of the preamp, tends to be lean and/or bright, the SP-10 MK2 may be your road to salvation. If you have a rather neutral or warm sounding system independent of the preamp, I would prefer to go with an SP-11 MK2.
The SP-16 is very good for the money. It is a bit more tubelike than some of the ARC preamps. It has nice bloom and air. Stay away from the LS-7,15, or 22. All sound too thin and sterile for my tastes even though still better than solid state preamps in their price range.
Call Dave Gordon, at ARC, and tell him that Larry Staples told you to call directly.
Dave is a square shooter who will be completely above board and helpful. I have known him for almost 20 years. He will definitely help you.