Audio Research Ref-1 vs sp10 mkII preamp

Curious if anyone has an opinion between the arc ref-1 and the sp10 mkII - sonically, that is. assume the sp10 has new tubes, upgraded caps, etc. how does its line stage compare with the much newer ref-1? i've seen highly modified sp10s for around the price of a used ref-1. i'm interested in buying one or the other. any help?
thanks in advance.
AAAAAAbsolutely SP 10 MkII; upgraded by Infinycaps & litz cable on phono & aux (cd) input; from Italy, Diver
Hello. I owned an SP-10 for 9 years (mid 80s to mid 90s). This was an awesome preamp for phono reproduction. When I finally bought a CD player, Pioneer PD65, the sound was ok but overall not musical. Was it partly the phono vs CD wars or was it also partly due to the SP-10's line stage? The answer was both.

I felt it was time to look into upgrading the SP-10 but as I quickly learned, ARC preamps are hit and miss. It seems like one really stands out from the crowd every 2 or 3 generations of ARC preamps. This is strange as ARC amps are continuously excellent. The SP-11 and SP-15 with all the rave reviews never did it for me in terms of musical enjoyment. The LS2 was absolutely terrible....way too analytical. Only when I sold the SP-10 did I realize what a gem this unit was when I was looking to get another preamp. Finally, the ARC LS5 was what I was looking for. This is a highly underrated preamp. But it's also a pain for those with anything other than all balanced components. But what this unit does is along the SP-10 qualities. This with the ARC PH2, has all that magical bloom and musicality of the SP-10 but with so much more resolution and extension at the frequency extremes the SP-10 could barely even hint of.

The Ref1 came out a couple years later, and then the LS5 MK III, followed which was a rework based on the REF1. I heard the LS5 III vs my MK II. Sonically they were nearly exact but the MK III had a more natural tonal balance on the top and yet even more resolution in the mids. Otherwise, they were so very close. And to my ears, as was the case with the ARC dealer, the LS5 III was preferred over the Ref1. The LS5 seemed to have that little bit more of warmth and seductiveness over the Ref1. And the Ref1 had a little more resolution. But these two models definitely have a sonic similarity. I have heard this view from so many other LS5 owners as well.

And by the way, concerning CD playback, it was so much improved with the LS5 over the SP-10. The SP-10 was an awesome piece for phono, but a very very poor choice for line-level components in my view.

I can not speak for what a hot-rodded SP-10 would sound like with all the latest cap and wire, etc., changes would do, but the stock SP-10 II is no match to the LS5/PH2 nor the Ref1 in either LP or CD playback.

And if you might think of other ARC preamps here, the LS15 and LS22 were not at all in the same league as the LS5 or Ref1. If you want that magical bloom and midrange magic of the SP-10, you won't find it in the 15 nor 22. An audition of these vs the LS5 indicated the 15 and 22 were not in the same league. These were again disappointing to me. ARC preamps clearly do not have a consistent sonic character from model to model. I have not heard the LS25 nor Ref2.

So if you are looking stricly for a line-stage preamp, the SP-10 really makes little to no sense. It's true magic lies in its phono playback. And even then, phono stages have come a long way since then.

Hopes this helps.


Over the years I have owned SP-10, SP-11 and have had much exposure to REF1, including extended use in my own system.
ARC is a fine company, and I haven't a bad thing to say about them....HOWEVER.

If I may suggest you demo a BAT VK50SE before you opt for either of the ARC choices that interest you.........
Big surprise awaits....

The sp10 mk2 is so good you cannot belive the magic of the project given to the audio community by the late Mr Johnson.
Needless to say, heavy mods are required: ps changed from electrolytics to full polyprops, this mod requires lifting of the entire ps chassis.
All capacitors in the conrol unit changed with Vcaps teflon reference, or V oil, pf values to audionote, volume pot changed tkd stepped top model, all resistors changed with vichay nudes/caddoks tfts/mills/kiwames..power cord changed to Vandenhul, plug from Chris Venhaus, rca females wbt, internal wiring vandenhul mcs 1000 doubled.
Photocouplers entirely bypassed, meaning you must switch the preamp on before the power amps and wait circa 4 minutes.Transistor amps not recommended......
hear to belive...ooops forgot..all tube sockets changed, fitted with siemens and telefunken NOS.
All soldering wonder solder signature.
Only active parts in the preamp are on off switch and volume control.
Cheers, its pure heaven....cartridge output must be no less then 1.6, no covers, two paps vents.
Yep, I had one as well, back in the day, and kept it a long, long time. Very
musical. I had ARC do various updates and upgrades to it over the years.
Biggest issue was microphonics (and as I recall), making sure the phono
section tubes were quiet and well-behaved.

With a smallish ARC tube amp and Crosby Quads, the thing sang.
It finally proved to be a little too noisy to work with my horn-based system,
which requires absolute quietude among the components. But, for a system
that isn't quite so sensitive to component noise, I would probably still make
beautiful music if it were thoroughly gone over. (That thing is pretty darn old
I replaced mine with a Lamm L2, which, superficially, resembled the SP-10.
Both of those pieces- SP-10 mk ii and Lamm L2 now with other presumably
happy owners, but great pieces. And John is right, the magic of the SP-10
was its phonostage.
EAT cool dampers are a must, especially on v1 v2 v9 v10
I was very lucky in the late 80s, bought a truck load of telefunkens and Siemens in holland for cheap; at the time everyone was wasting time going digital.
I enjoy zero noise, 0 microphonics today.
I do admit its a set up extremely hard to manage and achieve for the everyday audiophile. Every single solder joint has been taken care of, and in critical areas hard wiring is a must.
It took me over 20 years to get it right.
You also need a dedicated power supply in the house, feeding itself directly from the entry mains (Vandenhul cable carrying the current).
Similar story goes for my power amps (d115mk2 one per channel vertical biamp). All caps changed, internal wiring, additional outboard power caps, wbt connectors, gain attenuators bypassed (the ones in the back)all GE power tubes and driver.