MBL 9011 v/s Boulder 2050 monos

And these would be driving... what speakers?? And driven by what???
I.e. what's the system? All your parametres -- but esp. 2-3 -- refer to spkrs and amp-spkr interface primarily.

For example, 901 was more satisfactory driving Tannoy Westminsters than the expensive stereo Boulder (whatever its number).
Neither produced 1 or 2; 3 was OK on both probably due to spkrs set-up more than anything else.
What was wrong? Amps? Speaker cabinet? I don't know... Cheers

The preamp : MBL 6010D reference preamp
The speakers: Usher Be-10 / Kharma 3.2FE (own the 3.2)
Proac 1s (own these also)
CD Transport: Oracle 1000 (New)
DAC: PT P3A , P1A (BEst so far)
Speaker cables: Silver ovals Analysis plus
Ics: Nordost valhalla
I was hoping for a difference in sound characteristics. I own the Boulder 2050 monos right now & thinking if the MBL would sound more in tune with my stated preferences.
Is it worth the change ?
My impressions: Listening to these great amps in different setups does not make for fair comparisons, but here are my thoughts.
The MBL sounded more warmer and softer but with higher extension on the top. The boulder had better lows and also had a warm midrange but more to the neutral side.
Maybe boulder had better detail ???
Any input guys ???

Your question is really hard to answer. One of these amplifiers might sound better in your system depending on your speakers and preamp.

The best thing you can do is to try to borrow one of these amplifiers and listen for yourself.

What is the rest of your system? Perhaps the amplifier you are currently using is more than up to the task and there is something else in your system that needs to be changed.