I am a Pass Labs X2.5 preamplifier owner, as well as a Pass Labs 250.5 amplifier owner, and in my system the Pass components are detailed, but rather warm sounding. If I remember correctly your prior preamp could be configured as a passive preamp. If you were using it as a passive preamp then you have probably gotten used to rolled off high frequencies and this seems like too much information in comparison. Also, as you have already mentioned, the Pass X2.5 preamp may not be a good match with the rest of your components.
power cords make a big change in my system. i too had the adcom prior to my 2.5. i have also used signal cable cords. my favorite power cord for the money is $159 for a 4ft cord from rs audio... smoother sounding - not rolled off. i would not call it a tone control, but things are smoother. the low end is not as "full," but more under control. enjoy.
I've owned the X2.5 and the X-1 and both are near identical in sonics and thought them both to be quite neutral. At least with my line conditioners plugged into them.
I'll guess two possibilities as to what you may be experiencing:
1. Your system's sonic presentation is not properly weighted between the bass and high frequencies. Now with a preamp that allows more of the high frequencies to pass thru, the impression is the presentation is even more unbalanced. You seem to have already alluded that this could be a possibility. And it most likely is the bass that needs beefing up. Again, as you seem to indicate, this may best resolved by different amplification.
2. The ics and scs you are now using may be adding much grain, glare, and/or a digital hash. And again, the X2.5 will present more of this. I've owned the AZ Satoris as well as the Harmonic Tech Pro 9's. Same engineering principles, design philosophy, etc.. Not bad cables I suppose. But with the Audience Au24 speaker cables, the improvement were rather tremendous and much of that grain, glare, hash, etc. disappeared.
Essentially, the rest went away when I inserted the Au24 ics. Prior to that I owned Pure Note Epsilon Ref ics which were slightly better than the Harmonic Tech Pro Silway Mk II and Magic Link One ics prior to.
That may well take care of much of your problem. And if you did pursue the Audience Au24 line up, with a little work on your part, you should be able to get all of the Au24s for about the same price you can sell your existing cables.
Or for just a fraction of the price, you can try the new Anti-cables by Paul Speltz. These are easily the best speaker cable I've owned thus far (I've had them for two weeks now) and they only cost $60 for a 6ft pair.
To take care of the rest of any electrical-related issues, you should consider proper line conditioning.
I owned the X2 and thought it was neutral with a liquidty airy presentation not bright at all. I woud suggest selling your Proceed amp and getting a c-j MV-60, Quicksilver Mid-monos, or AES Sixpacs tube amp and your system will start to sing.
I have owned the X-250 and X-1. What is descriped above is accurate on their sound. When I tried the combo in a buddies system, it did not work and I heard the brightness that you heard. If I recall correctly, it seemed to come from the matching of the Pass gear to his speakers. There seemed to be a certain frequency that was moved forward in the presentation that made the system sound bright. I was using an Elrod EPS Sig 3 power cord so I felt that it was not the power cord. It also could have been the speaker cable and ICs. They were AZ Sil Ref ICs and Home Depot speaker cable. The Cardas Golden Hexlink 5-Cs seemed to reduce the edge or brightness. I'd try a few different cables to see if you can get ride of the brightness and if they don't work, it could be a speaker matching issue.
My personal opinion is that using cables as tone controls is just masking (or compensating for) other problems.
(I am not saying that cables make no difference.)
I am growing in the opinion that your system should sound in a manner you like with 'cheap' cables, where better cables simply are less restrictive and allow your gear to show through better; quite frankly better cables may reveal short comings in gear as much as help them.
Anyway, it's early, maybe I am not thinking clearly. :)
So to the point of the post, I think there are some issues in your system where you don't have a system match, outside of cables.
I own the X2.5 and definitely do not find it to be overtly bright, although it certainly provides a clean detailed presentation. I do have it matched with a X150.5 amp, so this synergy is certainly helpful. I have even compared it closely to the Densen pre-amp I was using previously as well as the Primare 5.1 HT pre-amp I use for film viewing/surround sound. The Densen is pretty well known for a 'Naim-like' signature high on PRAT...very musical - definitely not 'bright'. The Pass clearly was more open and relaxed sounding. The Primare is a pretty high-end piece and although it's primary focus is on the processing side of things, it is a pretty musical piece and it's pre-amp is no slouch. I wish it was as good as the Pass Labs since I'd love to consolidate my system...unfortunately it wasn't. This is of course based on my personal tastes and observations, but I might note that there is an issue of synergy in the amp/pre-amp/speaker chain. Hard to say really...I'd hate to see you give up on Pass since I think they make great gear but it's possible the Pass Labs doesn't fit your personal sonic tastes. FYI...even though Brian's probably correct that you won't want to rely on cables to fix something I do find Sonoran cables to be a very sweet complement to my Pass amp and preamp.
I have an X2.5 and don't find it to be bright at all. In my sytem is sounds neutral and clean. It will reprodouce what it is fed.
You might want to look at your source component, the Naim CD3.5 has a reputation for a forward midrange and high frequency brightness. Try to borrow an other CD player and see (hear) what happens.
Like Stehno and others said the X2.5 is allowing the high frequencies to 'pass' through more than did the Adcom. The X2.5 is a beautiful piece of equipment and I think I have a synergy mismatch with my amp or speakers. The Focus Audio have a very detailed high end (not bright in my opinion), but having had the Pass only a week, I'm going to give things more time before I make any major changes and might try a different pc. Thank you all for the excellent comments/suggestions!
I'm considering a Pass Lab x2.5 that's currently listed in Agon. Have a Levinson 27.5 amp and Thiel 2.4s; cdp to be determined. Is the Pass x2.5 a good choice from what's currently for sale in pre's from $1200-1800? I auditioned an old Classe DR-6 and was delighted with its warm, clear sound and 3D spaciousness, but had too much bkgrnd hiss with the Levinson. Any suggestions on pre's in this price range?
Also, I read that the Pass x2.5's volume control was digitally configurable from 1-100 so that you can maximize the number of steps based on your amp's sensitivity, and thus make each step quite small, not gigantic 3db steps?
I'm considering a Pass Lab x2.5 that's currently listed in Agon. Have a Levinson 27.5 amp and Thiel 2.4s
- Jim_wojno -
I have the Pass X1 (similar in sound as the X2.5) and the Thiel 2.4s like yours (amps Parasound Halo JC1s) and I found the X1 perfectly balanced airy super detailed and with fantastic soundstage
I have a 2.5 and don't find it bright at all. Probably system synergy isn't working.