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Rotel RMB-1575 a good match for B&W CM10's?

Most B&W dealers I've spoke to generally point to Rotel as a good match amp wise so I was thinking of going the Rotel RMB-1575 route to power my B&W  CM10 S2's, CM Centre 2 S2 and my 685's at the rear? Is this a sensible choice?

The Rotel RMB-1585 is also appealing but space would be a big challenge with this much larger option.

kdochert
caphill
673 posts
 
In regards to class D amps lacking bottom end oomph......imo not all class D amps perform or sound the same. Class D amps or digital amplifiers have come a long way and the class D or digital amplifier technology have greatly improved over time. If it was 20 yrs ago yes class D amps were inferior in comparison to analog (class AB or A) amplifiers. Don't hesitate about going class D nowadays. Especially these high end brands like Classe, Bel Canto, Theta Digital, etc make excellent class D amps. 

That being said, I highly recommend the Classe Sigma Amp5. The Sigma series is Classe's entry level series. It is a step up sonically from the big Rotel RMB-1585.

But the RMB-1585 is a great amp too especially considering its asking price and was built like a tank. Actually the Rotel RMB-1585 runs cool. Comes with 2 fans placed toward the back panel and the fans is barely inaudible. The internal heat management is superb with this amp. No matter how hard you drive it the amp will never get warm or hot. 
The sound is very fulsome, fluid very musical very smooth and has full midrange bloom  and has a bottom end grunt you desire but I found this amp lacking a bit in extracting all musical nuances and information, details, transparency and resolution in comparison to the Classe Sigma Amp5. 
The tonality is leaned towards the warm side of neutral. The RMB-1585 has a level of great warmth that people desire especially for listening to music. 

The Classe Sigma Amp5 however sounded more resolved, cleaner, faster with much better details, transparency than the Rotel RMB-1585. The Classe Sigma is a lot more revealing sounding amp without sounding harsh or bright and the Classe Sigma Amp5 excels in extracting all musical nuances details and information and with greater drive, rhythm, pace, timing and speed than the Rotel RMB-1585. It sounded clean, fast with more solid accurate imaging and greater soundstage than the Rotel. The imaging and soundstage is vast with 3D like. Overall the music or movies sounded and felt more alive with the Classe. Everything is popped with the Classe whereas with the Rotel as if there's haze blanketed the soundscape and things become more obscured whereas with the Classe everything becomes more solid and obvious. 

But the Classe Sigma Amp5 is a very revealing amp and will reveal the weaknesses of the source such as bad recordings, and qualities of your upstream electronics eg preamp/processor, source component (player), DAC, etc. It also reveals the weaknesses of your cables and speakers qualities. Make sure you get the good quality and the right cablings (speaker cables, interconnects, power cables, etc). And I wouldn't recommend using your Pioneer receiver as your preamp processor as the Classe Sigma Amp5 isn't forgiving of the source and quality of upstream electronics eg preamp, processor, etc. As your budget opens up more later down the road I would recommend that you upgrade your preamp processor and source component (player, etc). 
kdochert OP
20 posts
 
Ok thanks, I think I need to find some showrooms and listen to some different amps before I make any decisions.
auxinput
2,920 posts
 

It's true that some Class D offerings are better than others.  The Rotel may be based on an older design.  Some of these older designs had poor results because the frequency response was driven by the impedance curve of the speaker.  If the speaker had a flat 8 ohm impedance across the board, it would not matter, but most speakers have impedance all over the place, even dropping down to 2-3 ohms in the bass/midbass area.

The new nCore Class D circuit solves a lot of these problems.  Newer designs are also better.  The Classe Sigma may be a good design.  Another one you can look at is the PS Audio Steller series (M700 monoblock or S300 stereo).  The PS Audio use Class A input stage which really improves the richness and liveliness of the audio.

Another good contender for Class D is Nord Acoustics.  They have many different Class D amps using either nCore or ICE Class D circuits, up to 8 channels.  However, their best amps are the "Nord One UP" or Nord One SE" series.  These two series include the special Nord input buffer board which allows you to select one of two different discrete Class A input op amps.  (choice between Sparkos Labs or Sonic Imagery op amps, both are excellent).  The One UP series actually has a 3 channel model, so you could do your front 3 speakers with just this one amp.

The latest designs of these Class D amps are very clean sounding with absolutely no distortion or coloration.  I have heard that sometimes recording engineers like to use them because it shows exactly what is it the mix.  However, one thing I do not like about these Class D amps in general is the lack of "air" or high frequency response.  The end result is a sound that is so clean that it is almost too clean and lacks that "life" or "zest" that makes it real - Class D is almost artificially clean to my ears.  Don't get me wrong, there are a large amount of people who just love their Class D amps, but I would rather have a good Class AB for my own preferences.  If you think that the lack of high frequency "air" may bother you, I would suggest to look for a dealer that has a Class D amp offering and see how it sound to you - then compare directly to a good resolution Class AB.

caphill
673 posts
 
The Rotel RMB-1585 (class AB) isn’t based on older class AB design and is very capable amp and can handle low impedance loads with ease. Very dynamic amplifier with massive headroom. Dynamically it is on par with the Classe Sigma Amp5.
The Rotel RMB-1585 is huge very heavy and has two over-sized toroidal transformers main power supplies stacked up.

Classe uses its own proprietary class D design for their Sigma series amplifiers and wasn’t based on nCore Hypex module design. True, if I have the choice to choose between Classe Sigma amps (class D design) and Classe’s own class AB or class A designs (Delta series), then of course I will go with their class AB or A amplifiers but they are lot more expensive than their Sigma series amplifiers (class D). And Classe Delta series line have been discontinued last year and the new upcoming replacement Delta series products will be introduced either later in the year or next year and the their new Delta series amps will be class A design and they will be introduced soon. I had a chance to hear pre-production run of their new upcoming Delta Pre stereo preamp/DAC and a pair of their new upcoming Delta Mono monoblock amps (class A design) paired with the B&W 802 D3 speakers and they sounded spectacular together. But I was told that the retail price for their new upcoming Delta Mono monoblock amps will be around $20k and $10k for their new upcoming Delta Pre stereo preamp/DAC. 
Classe finally gets back to its root making class A design amps with their new upcoming Delta series amplifiers.

I agree that for listening to music I prefer class AB or A design amps to class D amps but for home theater class D amps would be fine.
auxinput
2,920 posts
 
@caphill - I was talking about the RMB-1575 that the OP currently owns and that we have all agreed is Class D.  I'm sure that the 1585 that is Class AB will be highly superior.
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