As you know I am NOT a fan of the XP-25 phono; I am a fan of my MODIFIED 25, but I still remain skeptical when people claim that the 17 is better than the stock 25. As to why I think all that is because reputable manufacturers carefully version their products, and that has been proven true time and time again. I think the 17 is a replacement for the 15, the 22 for the 20 and the 27 for the 25; but otherwise the 30 remains a statement product.
Thanks for your comments, Tasos. Yes, I understand that you bought the Pass phono as an interim solution because you were tired of waiting for Spectral to come out with a new phono, so I know you are not a fan. You did buy it after briefly hearing the Xono phono in my system. From what Pass tells me, the differences between the 15 and 17 include some of the modifications you made to the 25, like better shielding to the power supply and umbilical cable. The 17 does not have a separate power supply and umbilical, but those are significant sources of noise in the 25. The 17 may not suffer from those same issues and may in fact sound better. Of course I have not directly compared the 17 to the 25, but at least one guy at Pass told me that he preferred the 17 to the 25 during his long term listening. I have no reason to doubt him. The 27 should be even better maintaining their two price/performance levels.
I feel you would better off with a used 30, and I also think your prior assessments had been based on an overall less resolving system, nothing to do with your cables. Since then, the resolution of your system has improved significantly and your preamp purchase merits careful thinking.
I gave the purchase some careful thinking. I have had the XP20 since March, 2009, eight and a half years. Prior to the XP20, I had the X1 and was thinking of upgrading to Pass' then statement preamp, the three box X-0.2. I was told by the dealer that he and Pass Labs thought the newly developed and just released XP10 was better than the former statement X-0.2 still in production. In fact he "strongly recommended" that I get the slightly higher priced lower model one box XP10, over the statement three box X-0.2. The one box base model sounded BETTER than the former statement product according to the designers. So I saved a bit more and waited for a deal on the even better sounding second level product, the XP-20. I just reread my emails to Reno Hifi from 2008 discussing the X1 to XP10 or X0.2 upgrade path to refresh my memory.
Your thinking that the "statement product" can not be surpassed by a newer, lower model was refuted by Pass Labs and Reno Hifi back in 2008 and even addressed in a review at the time by HiFi Unlimited in 2011 regarding the new XP-20 and the former flagship, three box X-0.2:
"The moment I fired up the XP-20, I was thinking to my self "now this is more like it!" The two box XP-20 came with very bold expectations as the foreign reviews already claimed that it's so... good, that it made the much more expensive and higher end X-0.2, three box model redundant."
and this one from a later article in HiFi Unlimited comparing the X-0.2 directly to the XP-20:
"The X-0.2 offers subliminal, textured, and solid bass reproduction. It's noise floor levels are not as low as the latest XP-20 that good ol' Odiosleuth had up graded to recently, but still amongst the most quiet of preamps as they come. Out right transparency and low level signal preservation is another area where the newer preamp designs like the XP-20 has clearly marched on. So clearly, statements about the XP-20 out performing the Pass(t) statement product are not without substance."
So, apparently, here is a clear case of a former statement flagship product being surpassed by a newer product. Pass Labs may have just done it again with the XP-22 which benefits from technology first developed in the much more expensive flagship XS line. I don't know, but history does have a way of repeating itself, and it is clear that Pass knows how to develop and market new products.
I have given this new preamp purchase some careful thinking, in fact since the new models were announced a while ago. I have not heard the XP20 yet, so I can not have directly compared it to the current statement XP30. I don't know which is better, but based on both the story of the earlier statement/flagship being surpassed by the then new XP10 base model PLUS the auditioning in my system of the XP30 a couple of years ago and preferring my XP20 after a direct comparison (even with cables that were not re calibrated for the lower output impedance, and which aren't the issue anyway), I feel confident that I am making the right choice, for me, at this moment. If in a couple of years if there is indeed a new three box XP32 available, that may be worth considering too. There are just too many examples of former flagship products being surpassed by later generation technology. Magico has done the same thing a few times and I will soon find out if Pass has done it again like they did ten years ago in 2008. I would not be surprised.