Considering the Parasound A23+ amplifier

I highly doubt that the Pass XA25 is causing the lean sound with bright highs.  I suspect it is something else.  Maybe something in your preamp, or the type of 6SN7 tubes?  Or are you using silver wiring - as this will definitely slant the sound towards lean/bright if you have too much silver.

As far as Parasound A23+ or A21 goes, I don't think it will solve your problem.  It may make sound even leaner than the Pass Labs (the Pass XA25 is going to be biased much higher into Class A and providing a thicker sound).  I have heard the XA25 and it's definitely not "lean" sounding.

The Paraound amps have an incredibly clean midrange, but the high frequencies can come across a bit dry (in my system it lacked engaging sound quality).  You can fix with a fuse upgrade, but it can become even slower.  I'm not sure if this is what you want since it still will not be as "thick/full" sounding as the XA25.

If you want an amplifier that is full sounding but with softer and laid back highs, I would recommend a McIntosh amplifier.  But like I said, I think something else is going on in your system that is causing the lean/bright effect.

You should be able to pickup a 2-4 year old Parasound A21 for the same price or under the A23+ price new. If set on Parasound that’s what I would do. There are probably lots of other great amps new and used in that range as well. The A21 is definitely on the warmer side. I find it also very detailed and dynamic as well. Great voicing IMO. Is it neutral?? No idea but sounds great to me.

Yes, I have not ruled out the possibility of the problem being something with my preamp. I am continuing to research this. I will get back as I discover more. Might have to determine a better description for the problem.

I have looked into the Parasound A21+ however I don't need that much power or the weight. That amp weighs close to 1/2 what I do.
I was thinking the Parasound was more on the warm side than the XA25 which is unique for a Pass amp.

Stereophile gave the XA 25 a glowing review, as someone  above mentioned it could be cables, other equipment or break-in time these issues were also talked about in the review. Good luck

I am not sure that the issue I am having with my XA25 is typical to the model. I am not convinced that what I am hearing can be addressed with cables, break-in or warm-up.   I have spoken to Pass Lab personel and have determined that my unit was manufactured last June and is still under warranty.  If the issue is with my preamp I am confident Aric will help me out. 

Based on my take from reviews and this forum I believe the XA25 to be more on the lean side, more transparent, than the XA30.5 or 30.8. The 30.5 having the most bloom of the three. Known to be quite distinct from the other Pass Labs or First Watt amplifiers.