Who out there knows about Audio Research Pre's???

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.