That I have no idea. Preamp can be very individual, hard to predict, it's not like power amp part of the Denon that judging by the size and weight and last but not the least, the price, that you just cannot have 5 125W power amps fit in that little chassis and for that money, that it can be that good.
In my case, the Acurus power amp I got sure improved the sound by a mile even though I use the preamp from the Harmon Kardon. I used the HK as preamp for like 15 years before I switch to a better one. To me, the power amp is a lot more critical particularly with 4ohm speakers.
Remember, all these are just an education guess. You have to start somewhere, the power amp would be the one I would change given the info I have. It is my opinion not to buy a better all-in-one AVR unit. The reason is because the preamp, the AV processor are like fashion, in a few years, they might be obsoleted. Then you have to throw away the power amp with it and buy another one. Power amps don't change, the power amps made 30 years ago will work just as good as the same quality power amp as technology have not change much. You invest in a good power amp, it will serve you well for years to come. Then just change the preamp and AV front end like fashion.
If you are willing to take a chance on used, there are good power amp for about $600 to $800. Amps like Adcom GFA555, GFA5500 to name a few. These amps are good enough even if you decide to upgrade your speakers in the future. But of cause, you have to take a chance on a used one.
I don't know what amp has warm tube sound, someone else might have opinion. You have a bookshelf speaker, lagging bottom is not unusual. You might need a sub to give you the bottom. But that's another story for another day.
Own designed power amp, own designed preamp, JM LAB Spectral 913.1 speakers, Rythmik F12SE sub.
Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.
Last edited by alan0354; 04-21-2019 at 03:40 PM.