What is lacking with your Pass amp? Are you sure the issues reside with your amp? Pass makes very good equipment, so what is missing? More power needed? My recommendation is to find a good store, establish a relationship and borrow the Bolder amp and Rowland amp for a week at a time and take it home, insert it into your system, without changing anything else and listen. Then make your decision. Don't buy first without trying it.
A good store will take your credit card information and let you take equipment home to audition for a week. That way you can directly compare the amps with your existing amp in your home with your equipment. Again, just insert the amp and don't change anything else. Then if you like it, you tell them to charge your card. If you don't you return it and they don't charge your card.
This works for me all the time at my favorite store in San Diego. For expensive equipment, I don't buy until after I audition. If the store won't, then find another store that will or friends that will let you borrow it. Sometimes in rural areas this is not possible or you may have to drive some distance but, the worst thing is to listen in the store, take it home and it sounds terrible.
But, why are you considering replacing your Pass amp?
enjoy
