SMSL VMV A2 Review (Stereo Amplifier & DAC)

[Helicopter]

Thanks Amir. It is nice to see such power and SINAD from a chip amp. However, the price seems too high. At least this won't discourage Topping from doing something similar, but better. I agree with comments that DAC like this doesn't really fit the product. Loxjie A30 still nails the category. Too bad they didn't just make something like A30 with this power and SINAD for $300-500.

 

[amper42]

Would it be possible to add CD testing to DAC reviews since many of the new DAC chipsets don't work with CD players?

 

[617]

for 1000$ it seems absolutely irrevelevant to me, there is better alternatives

What alternatives would you suggest with this kind of performance and a built in DAC?

 

[JSmith]

Signal to noise ration

I was unaware there was so little SNR around that it needed to be rationed...

Looks like a good little amp though.



JSmith

 

[Rottmannash]

You missed a big minus on the Denon. You can't buy it anymore.

Is this the same AVR?

 

[vkvedam]

Interesting findings, it's in a funny place in the chain though. Doesn't have the streaming capabilities or else would be a direct competition to Power Node (2021). Of course the BluOS implementation would be light years ahead I suppose. Overall pricey as others pointed out.

 

[dorirod]

Is this the same AVR?

That appears to be a non-US version (220V).

 

[Njoy]

Thanks for the review.I am confused,does it have a DAC or the PCM signal been converted to PWM signals,then fed into class D amplifier.

 

[Rottmannash]

That appears to be a non-US version (220V).

its being sold here in Nashville by Electronic Express. I know the owners-not sure how they're getting a unit this old for sale new...how can you tell it's a non US version?

 

[AndreaT]

Most excellent review. Any further SINAD advantage using AES digital input vs. coax/usb?

 

[SylphAudio]

I guess the analog input is being fed to a separate (inferior) ADC circuit, then class-d chip used might be a digital input type and has a built-in DAC, so the digital input measures better.

I'm doubting the input frequency independence in power vs distortion graph. 5W at 4 ohms is at 56dB SINAD. Maybe it requires slower interval measurements.

Low distortion up to 50W is impressive!

 

[trashken]

I got this from China for USD 700. Was planning to use it for my record player but guess I should use it on my desktop set up instead.

 

[amirm]

Would it be possible to add CD testing to DAC reviews since many of the new DAC chipsets don't work with CD players?

You say that so generically. You mean test with any random CD player? Or some with certain characteristic? I can test for level, jitter or both but need to know the nature of the problem.

 

[amirm]

I'm doubting the input frequency independence in power vs distortion graph. 5W at 4 ohms is at 56dB SINAD. Maybe it requires slower interval measurements.

That measurement uses wider bandwidth than the dashboard so it can capture harmonics of 20 kHz. So SINAD is naturally lower there especially for this chip amp as it has lots of ultrasonic noise just outside of the audible band.

 

[Njoy]

Just got it from their site.Looks like no DAC.

 

[SylphAudio]

That measurement uses wider bandwidth than the dashboard so it can capture harmonics of 20 kHz. So SINAD is naturally lower there especially for this chip amp as it has lots of ultrasonic noise just outside of the audible band.

Got it, the point of 45kHz bandwidth is to show frequency independence even with 20kHz input signal.

 

[PeteL]

So finally a chip amp that compete. To me this is big news, really big news.

 

[gvl]

@amirm, can we see the wideband spectrum?

 

[gvl]

Is the box tall enough to fit an NCore module so it can be repurpused after the amp dies? Good thing there's enough room in the back for the second XLR input.

 

[Francis Vaughan]

Hmmm. The SMSL web site has exactly the same digram depicting the feedback loop as we saw for the SA400. That is the AX5689 PWM controller. Indeed it is hard to imagine that this amp is anything but an SA400 power amp stage with digital inputs. Amir measured exactly the same power ouput curves for both, but the SINAD is better here. Again, the ST part is the output driver only, and not the full class D amp. All digital processing and PWM control, just like the SA400, is done in the AX5689.

This amp adds a separate ADC for analog input, whereas the suspicion is that the SA400 uses spare ADCs from the AX5689 and implements its tone controls and volume control in the analog domain.

What becomes interesting is the improved performance we see. The SA400 is an odd device, it spends a lot of time messing about with some ideal of analog processing purity, and then throws it away at the last moment. Here we see the same basics, but with a digital chain that works well, and an analog chain that despite use of a discrete TI ADC, (PCM1804 with OPA1608 buffers are claimed) mucks it up. Something has gone wrong with the analog here, it should not measure so badly.

So, another almost there product. But it steps up one notch past the SA400 with its use of the AX5689 PWM controller, and starts to knock on nCores's door. Not quite there yet however.

The basic configuration almost gets there. Add proper DSP EQ (including subwoofer control) and fix the analog input and it would be a near perfect package for many users. Price needs work, but it isn't terrible.