Upgrade from PM 7001 KI to 2275?

[disfunktor]

I always loved the looks, and sound reviews of 2270, 2275, 2285 and 2325s. I heard (and loved very much) the 2285 in action, but only briefly and in a relatively unfamiliar setup (AR9 speakers) and an unfamiliar ambient (a rather big living room dedicated to hifi stereo), so I cannot really put it in place. I have now a chance to get a mint looking (but not yet tested) 2275. The price is really hefty (1000€), as these are very scarce in my country, and I am wondering if there is a possibility of getting disappointed by the performance, considering the price. Also, there are servicing and maintenance issues with such old devices. I currently have the Marantz PM 7001 KI paired with TDL RTL3s and source is 24/192 external DAC. I generally like this setup.
When it's past 15% volume it sounds very good. Detailed and balanced with a little bit of a warm hint which I like. What I don't like is that it doesn't sound as good when played quietly, which lately seems to happen quite often since the system has been banned to my office. It just sounds flat and, I don't know; bland. So I tend to push up bass slightly and treble significantly when I play quietly. This helps, but it's still not where I would want it. It's almost like it misses the "loudness" mode. I'm not sure. Would 2270/2275/2285 be an upgrade in that respect and in general? Would I get a nice warm, tube-like sound with detail on lower volume too? Or would I lack the detail and clarity and hate myself for spending a lot of money? What's your thought on this?