10-29-13: MapmanHi Mapman,
Not certain but I think frequency bandwidth is the main thing that a good SS pre-amp might be able to best the ARC in. THat an dnoise levels, but noise levels have not been a big issue with the ARC either, though I have had to replace tubes a couple time over the years to keep things that way, espeically the #1 tube in the phono stage.
I do not use the phono stage that much these days yet the 3 pho stage tubes are in play whenever I use the ARC, shortening their life.
At this stage, I'm just thinking that I might be better served over the long term by a good SS pre-amp with no phono and adding a separate phono stage (maybe tube) that is only on when I use it.
I have no specific preamp suggestions to offer (some good ones appear to have been made by the others already), but I would offer the following thoughts:
1)Regarding high frequency bandwidth, by far a greater limiting factor than the preamp appears to be your amplifier. The 3db bandwidth of the SP16's line section is specified to exceed a range of 0.5 Hz to 100 kHz, while as shown in JA's measurements the upper 3db frequency of the amp is in the area of only 25 to 40 kHz, depending on the impedance of the speakers at high frequencies. And into 4 ohms, significant (~1db) rolloff occurs at about 20 kHz.
2)JA's measurements of the amplifier's intermodulation distortion performance are suggestive of the possibility that using it in conjunction with a preamp having very wide bandwidth might even be audibly counter-productive.
3)If you want to ultimately consider a tube-based phono stage, FWIW if I were considering a phono stage upgrade now, based on many comments I have read number 1 on my list of candidates would be the Herron VTPH-2, at $3,650.
Best regards,
-- Al