Pass Labs users. Next upgrade?

I just upgraded my Amp from a X-150 to an X-350 and love the increased dynamics in my large room. I find them to be similar sounding amps. More fineness, control and dynamics w/ the X-350. My Top end, depending on the recording, can be harsh and fatuging at high listening levels still,(not as bad). Next move, Should I replace my Adcom GFP-750 Pre, the preamp people love to hate (I can only compare it to a Placette Line stage, similar results in my system). I think the Adcom is fine in passive mode and a waste of time in active mode.
Should I spend my dough on a 2.5 or X-1 preamp or go to the X-350.5 Amp upgrade for the most bang for the buck?
Trl Modified Sony SACD-2000 ES , Sansui Tu-717 Tuner
Speakers: Audio Physic Virgo II's and Two Rel Storm III Subs,"a tasty combo"
I love my X-350 amp. Im using a levinson 32 preamp.A modified wadia 850 cdp and nordost quattro fil ic,with my martin logan monolithIII speakers. What wires are you using? Are you using a line conditioner? Im using a audio magic stealth. That made my system open up.I have not heard the X-350.5, heard good things about it, but I really love my X-350,I wont sell it just yet. lots of preamps out there.much better than your adcom 750. check the threads on preamps. GOOD LUCK
Go with the.5 upgrade.I had X-1 and sold it to upgrade.
I'm surprised. Pass amps and passive pre's aren't usually a happy marriage because of low sensitivity and impedance. My ex would agree.

Tube pre's like BAT, Manley, and VTL would tame the highs, perhaps too much with Sovteks. The Pass pre's are highly transparent and honest, almost brutal with poor recordings. If passives work for you, the Bent Audio TAP will be more dynamic with a touch of warmth.

The .5 upgrade is supposed to be fairly substantial, for an upgrade. Don't expect miracles. That's a lot of amp for 90 dB speakers. You can never have too much.

Not familiar with Audio Physic... unusual tweeter.
Since I have a fairly long history with Pass gear and many brands of tube gear, I would like to offer my two cents. I also owned an X 350. Thsi was after owning a Sonic Fronties Power 2. I felt that I was missing a little with the SF am so I went to solid state. I felt that I was missing a little with the 350. So I upgraded to the 350.5 and wow! For the first time ever I felt that there wasnt a comprimise. The .5 gives the best of both words. It has thundering bass with sweet and delicate highs, and a midrange to die for. To me the .5 upgrade is a no brainer. Secondly, I mated it with an XO.2 preamp and the combination is a match made in heaven. The transparency, musciality and dynamics are jaw dropping. For the first time I have no desire to change my electronics. I am using this setup with 94db speakers, Tyler Acousitcs Woodmere. Source is a Levinson 31.5 and 30.6 combo. So what I am trying to get across is that the .5 upgrade with the X-1 preamp (because most say there isn't a significant sonic difference between the XO2 and the X-1)might just be your path to nirvana.

Enjoy your hunt
The .5 amps are definately an improvement in the Pass line. I also had the adcom and placette preamps. I purchased the x-1 preamp and it was the best move I made. Having the amp and preamp from the same manufacturer should perform a perfect synergy for you. It did me.
350.5 is a awesome sounding Amp. Dont hesitate, go for it!
I have read many threads descibing the 350 or the 250 as being hard in the midrange.
I have also read that the 350.5 version excells in the midrange.
So, I bought one to use with my APL Player direct to the Amp.
Very Mellow sound .Again, awesome Amp!
Null 1, I'm useing Analysis Plus Oval 9's speaker cables, M.A.S. Xlr interconnects and Pass Labs supplied power cords. On My TRL Mod SACD player I have a TRL Silver power cord, I forget the model.
I also find some recordings a bit harsh.But it is the cd,not the system. I also have some recordings that are fantastic. Have you done anything with your audio room? Bass traps, etc.....Your room is very important also. What kind of power conditioner are you using? That will also take some harshness out. What kind of rack are you using? That can change things even more, Do yo have your speaker wires off the floor? So many things to check before you upgrade.Id still change your preamp, the rest of your system is much better than your preamp.
Null1, I have no room treatments and I don't use a power conditioner. I have my system in the main living area. I would be afraid for my personal safety if I attempted to make my audio presence dominate my wife's decor. I don't have problems intergrating my speakers and subs.. they match seamlessly great bass!... higher mids and highs can be harsh though at higher spl's.
I am an Electrician. At one point in my life, back in the disco era, I ran circuits for Live and D.J. music systems. So I have 2 dedicated 20 amp circuits. One for Amplification and the other for source componets. My neutral and mechanical grounds are not bonded (they are grounded independently)I also use audio quailty outlets( all copper, no brass parts) My Amp circuit is run W/ #10 solid copper wire(less voltage drop during periods of higher demand). They are as quiet as any residental circuits can be
Ditch the Adcom for about any preamp, but the Pass X-1 or about any of the Audio Reseach preamps would be great choices. I'm sure the 350.5 is better, but the 350 is a very good amp. The Adcom preamp is a major limiting factor in your system.
9rw, Are you talking tube or solid state when recommending Audio Research? There are so many A.R. pre's on the used market. What have you used w/ your X-350? If you are not familiar with my Audio Physic Virgo's they have a similar sound to Magnapan and other Electostatics...(but are not). They just tend to get a little sharp in the highs.
I'm really surprised the Adcom does't match up better with the Pass Amps. I had the X-150 first, with the same results. I believe Wayne Colburn of Pass designed the Adcom 750 and is just a less complicated design than the Pass Aleph P.
Gandme: I used a Pass X1 and ARC LS25 with my X350. Both were good, but the X1 was better -- in my opinion. It had better dynamics and better extension (highs and lows). As for ARC preamps, I was mainly referring to the tube preamps, but the old LS3 was a nice preamp, too.
Thank you all for your help! I've narrowed my choices to an X-1 or X-0.2 (possible trouble in paradise W/ the 0.2 price). It probably makes sense to stay with Pass products for the synergy. The next logical upgrade would be the X-350.5. The X-350 is the best Amp I've had in my I don't know why I'm even discussing replacing it! (as my wife likes to point out,"It's never going to stop, is it!"). I wish I could A/B this stuff in my living room with several other pairs of ears and a glass of Red!
Cheers to all, Greg
Greg,I believe we are married to the same woman!!Also,while I too like a good(cheap)red,my audio "could care less" wife prefers a nice Liebfraumilch,or sweet Reisling.
BTW,I have recently heard the ASR Emitter amp on the big Nola system.Fine sound,but in all honesty,when I was auditioning it,I kept thinking how close the new Pass 350.5 sounded compared to the German amp(I own neither,yet can appreciate a good product,which they both are).A good deal less money,as well.Think of how much fine wine could be consumed,with the difference.Which would equate to NO audible difference,once one was imbibed -:)

sirspeedy, Let's face it, the main factors to system synergy are in different order for everyone.
Spouse,Room response,Quaility of equip, recording quailty and amount we have or have not imbibed!
By the way I had a truely great Zinfandel from Black Sheep Winery, 2000 Clockspring Vineyard, in Amador County Ca. It would bring anyone's system up a notch!
Cheers, Greg
I took 9rw's advice. I bought a refurbed Pass Labs X-1 from Reno Hifi. It's dead quite, with much more finess, a huge sound stage! My highs are less bright and more natural. The base response is also tighter... go figure. Anyone looking for a Adcom GFP-750?. I think I will A/B them this weekend and really try to get a solid understanding of the Adcom's strenth and weekness.
Gandme: I'm glad you like the X1. It will likely get even better with more break-in time -- assuming the Pass folks replaced several parts. About the only thing I didn't care for was its operating system -- and the remote -- but I got used to both rather quickly.