Rcprince: Yes, with the LS5 being truly balanced XLR ins/outs only, this does have the potential to change things for someone whose system is all RCA connections. At the beginning, I used adaptors for my single-ended CD player and tuner. The '-' phase input is simply grounded so only the '+' is used and this worked mighty fine. Just about any amp these days has balanced inputs. And whatever you do, stay away from those BL1,2,3 conversion boxes. The extra stages and interconnects do far more harm than the benefit of converting single-end/balanced.
Growlar: The Mk I had 2 types of tubes for the 10 total. This was at the time when a shortage of 6922 was thought to become a reality. The II switched to 10 6922's when these tubes, Sovteks, were suddenly plentiful from the former USSR. There was a claimed reduction in noise. Both of these models had a switchable 30db/12db gain. But I always ran my II at 30db as the 12db setting had a reduction in 3-dimensionality.
The MK III took the audio circuit from the Ref 1 and amazingly retained all of the II's sonics. How they did this was beyond me, but it was far more neutral on the top. The I/II had a little excessive sibilance in the upper freqs that can be a bit annoying once you hear the III seconds later. But the II has a little more bass weight and authority. The III's strength of more natural tonal balance and its higher resolution, especially in the mids, won me over after owning the II for 7 years. The III typically was factory set as 12db, but a change of 8 resistors takes it up to 18db. I changed mine to 18db and this worked much better for phono sources. And ARC claimed the noise level to be a little lower with the 18db.
As for the holographics of the SP-10, oh man yes, the LS5 in any version has this in spades. Without it, I would have abandoned ARC as none of their other products had this. The LS2/15/22 all failed miserably in this area. If you're a fanatic of harmonic richness, 3-dimensionality, long decay of notes, for the money, the LS5 is unbeatable.
As for a phono stage, it's pretty tough to find one that has the same magnitude of strength in terms of bloom and decay unless you start to get serious at expense. I have an Aesthetix Io and this with Telefunken tubes brings on a level of decay and 3-dimensionality that simply was far ahead of the solid state ARC PH2 and tube BAT VK-P10 phono stages I had before.
I wish there were a way for you to hear the SP-10 vs the LS5 for line sources so you could hear for yourself how dated the SP-10 is here. For me the LS5/PH2 really did it all that the SP-10 did. I was not wanting for more bloom with this pair following my 8 years with the SP-10. But something like the LS5/Io or even more so, my current BAT 31SE/Io destroys the LS5/PH2 in the magic. But now we are way beyond your budget.
I have heard that people use the SP-10 for its phono stage only, using the tape out lines to drive a line stage. That could be an ultimate option for you by starting out with the SP-10. But still, you have to keep the line stage tubes in the SP-10 to keep its power supply stable.
Ultimately, if you want that tube phono magic, and in the line stage as well, it's going to cost you no matter what. Just try and listen to these products, next to each other in the same system so you can hear for yourself their strengths/weaknesses.
One final thing to remember, just because a unit has tubes does not guarantee anything that you will get the tube magic warmth, bloom, decay, etc. You have to listen to hear it for yourself.
Sorry for rambling so darn much.
John
