Yes - the Marantz preamp will limit performance, but there is something else to consider. Especially since your speakers are relatively efficient.
I have a lot of experience with Pass amplifiers (we currently own 5).
First, there is a very significant difference between a X-150.8 and a X-250.8 (the 250.8 is much better).
Second, there is even a bigger difference between the X-250.8 and the XA-30.8. The 30.8 sounds better, much better! I've listened to and compared both of these .5 series amplifiers and we used a 30.5 on our main speakers instead of our 250.5 in a relatively high end system - until we upgraded to our current XA-200.5's.
The only thing the 30.8 will give up to the 250.8 will be the dynamic impacts of bass. Like the dynamics of a drum. Sustained bass notes will be fine. Everything else will be much better with the 30.8. Don't take my word / experience for it, call Pass and ask them this for yourself.
Better yet, find a Pass dealer and listen to the X and XA amplifiers before you decide. It would be worth investing a weekend of time and travel to do this.
IMHO - upgrade the amplifier to a 30.8 and down the road get a good analog pre-amp with home theater pass through. We enjoyed our 30.5 for 3 1/2 years before upgrading to our 200.5's.
Each upgrade will be like listening to a new system. And you'll continue to enjoy your music along the way - which is what it's all about.
I have a lot of experience with Pass amplifiers (we currently own 5).
First, there is a very significant difference between a X-150.8 and a X-250.8 (the 250.8 is much better).
Second, there is even a bigger difference between the X-250.8 and the XA-30.8. The 30.8 sounds better, much better! I've listened to and compared both of these .5 series amplifiers and we used a 30.5 on our main speakers instead of our 250.5 in a relatively high end system - until we upgraded to our current XA-200.5's.
The only thing the 30.8 will give up to the 250.8 will be the dynamic impacts of bass. Like the dynamics of a drum. Sustained bass notes will be fine. Everything else will be much better with the 30.8. Don't take my word / experience for it, call Pass and ask them this for yourself.
Better yet, find a Pass dealer and listen to the X and XA amplifiers before you decide. It would be worth investing a weekend of time and travel to do this.
IMHO - upgrade the amplifier to a 30.8 and down the road get a good analog pre-amp with home theater pass through. We enjoyed our 30.5 for 3 1/2 years before upgrading to our 200.5's.
Each upgrade will be like listening to a new system. And you'll continue to enjoy your music along the way - which is what it's all about.