Bombaywalla,
Hopefully you will get a chance to hear some of the products, that you did not like in your friend's system, in the context of another system.....perhaps your own. Claiming that because you heard one power amp from a company, you know the house sound of that company, is not realistic. Many companies, ARC included, have a way of abruptly changing from one classic sound to another that is nothing remotely close only to come full circle and return to what they had a decade before. And the idea that a top-of-the-line model's "technology" trickles down to the lesser costly models is something we hope to be the case, but again, I have seen this not be the case several times. Several models in a line can ultimately not sound at all similar.
You said the sound was mediocre but you never detailed what made you come to this conclusion. Could it simply have been the room?
And because you know the Groneberg cable sound so well, you have eliminated this? Huh? Time and time again, I have found the IC between line and amp to be the most critical. With ARC gear, a couple of my favorite cable lines, SilverAudio and HarmonicTech just did not work well from line to amp but were excellent tonearm and speaker cabling. The NBS or Cardas Golden Cross were much preferred in this link. But elsewhere, I liked the SilverAudio IC over the Cardas.
What an IC sounds like from DAC to line or phono stage to line, is not necessarily what it sounds like from line to amp. So no, the "sound" of the cable can not simply be known; it is greatly influenced by the components it connects.
Concerning the Ref1, I was a long time (8+ years) owner of the LS5 which I preferred over the Ref1 because of the LS5's more "warmth" and "bloomy" sound. This difference was subtle but I liked the LS5. The Ref1 was clearly more resolving and tonally coherent. In the overall scheme of things, they were nearly identical. And neither of these products can be blamed for being the cause of a mediocre sounding system unless there was something severely wrong elsewhere. As GMorris states, it might not be someone's type of sound, but a poor product it is not.
And what do you mean the modified SP-6 out distanced the stock Ref1? Did you actually compare these two products in the same system? Or are you judging the sound of each in the context of two different systems? And what was the difference? ... tonality, noise, resolution, frequency extreme extension? Blanket statements of this is "better" than that have no value without further details to the differences. And if the comparison was not in the same system, preferably right there at the same time, it is silly to claim anything about one product against the other.
I have owned several components in the system you described and the one product I would question is the PH3. This is the most fatiguing phono stage I have heard in a long time. It sounds nice at the start but quickly had me eager to try any number of other such products. The PH2 destroyed the overrated PH3 by significant margins in lower noise and neutrality to just name two. The Ref1 deserves more than the PH3 and for that matter, the 17D (which I also owned at one time).
One thing I have learned many times is to NEVER judge a product in too critical of a manner unless I can take it home and try it out in my system for at least a few days to hear how it compares to what I already own and to the sound for which I am familiar.
Rather than look for a single scapegoat for mediocre sound, I would suggest it could easily have more to do with a poorly configured and setup system, than the fault(s) of any one element in the system. It is like someone getting a copy of Stereophile, buying all "Class A" rated components and claiming they have a musical system. It's just not that simple. In fact you're more likely to find musical success to do this at the "Class B" level.
John