Integrated Amplifier for Monitor Audio Silver S2 Speakers

After looking at both the subjective parts and the measurement-based parts of John Atkinson's review of your speakers, and after looking at descriptions and specs of the NAD C356BEE (although I'm not sure if that is the version of the C356 you are using), my suspicion is that BOTH the amp and the speakers are contributing to the lack of detail you described.  With the speakers probably contributing somewhat more significantly.  For example, from the review of the speakers:

The most obvious characteristic of the Silver S2's sonic signature was its mellow treble....
...the speaker does have an identifiable character, being balanced on the warm, mellow side, this is probably a good thing, given inexpensive electronics' tendency to have glary trebles....
... The low-frequency -6dB point coincides with the port tuning frequency of 42Hz, but a slight energy excess in the upper bass is visible. Together with the overall depressed level of the tweeter, this will give rise to the warm, rather mellow balance I heard.

All of these characteristics are consistent with compromised presentation of detail.

Before proceeding any further, here are some things that occur to me that might be worth trying if you already haven't:

1)Position the speakers so that the tweeters are aimed directly at the listening position, and are at or close to ear level.

2)Turn off the amp's soft clipping feature, if you have been using it.  (Although when you do that be careful not to turn up the volume high enough to cause clipping distortion, which would be obvious on dynamic peaks in the music).

3)Activate the amp's tone defeat function, to take the bass and treble controls out of the signal path.  (Tone controls can often have adverse effects on transparency, even when set to their neutral position.  Especially in relatively inexpensive designs).

4)But also try turning off the tone defeat function, and using the amp's tone controls to either boost the treble a bit, or reduce the bass a bit, or both.

Good luck.  Regards,
-- Al
 

Hi Al,
Very good suggestions from you that are cost free and simple to do. His speakers seem capable of reasonable detail with a better quality amplifier.  Note Djengan's description of the sound when the Accuphase replaced the NAD. Definitely more detail/better sound quality   extracted.  So  it appears that these speakers have potential that's exploited with the use of a superior power amplifier. 

+1 Mb 1 audio, oh so true regarding price/performance. 
Charles 

I just noticed from reading one of your other posts that you have an Oppo 103. If you're willing to conduct a simple experiment, I think you'll find the results worth while. If you look on the back of your NAD, you'll see that the amp and preamp sections are jumped externally. This means that you can use it just as an amp or just as a preamp, and not have the signal pass through the component you're not using. Remove the jumpers and run a pair of interconnects from the analog output on your Oppo to the amp in of your NAD. Use the volume control on the Oppo. 

The reason for this, is that preamps make a much bigger difference then most people realize. If you go direct, you shouldn't have any problem hearing a difference. Most likely the change will be good. There's too many variables to say exactly how much of a difference it will make, but its absolutely worth a try. The results you get may give you some insight on how to proceed.

I'm assuming all of your equipment is broken in, and you've tried some different placement options for your speakers. Also, I'm familiar with both your amp and speakers. You should be getting some good sound. Ultimately, they may not be to your taste, bit I think you should do as much as possible to make sure there really is a problem.

When you have an issue, or get frustrated, its very easy to pull your best components off the rack and get rid of them, thinking you've fixed the problem. 

++Viridian. Spend more on amplification. Information lost cannot be regenerated by even the most expensive speakers.