SMSL VMV VA2

Description

The VMV product line is SMSL's upscale series of products. Exhibiting better design, construction and appearance they certainly have earned that title.
This model is the Headphone Amplifier with two (low & high) inputs to tailor the sensitivity of your headphone for the right amount of power.
This an example of a review by the highly regarded "Audio Science"
#1
This is a review and detailed measurements of the (SMSL) VMV VA2 Headphone Amplifier.
VMV is SMSL's higher up brand and as such, the VA2 comes in a solid aluminum case that weighs a good bit but otherwise is ordinary:
The volume control can only be grabbed from the top which I found a bit hard to turn and adjust. If the music is too loud all of a sudden, you will have have a hard time lowering its volume as you have to lift your finger when you get to the end of the slot and start over.
The two headphone connectors made me think one had higher gain, and the other, lower gain. Turns out this was a mistake as you see later in the measurements section.
The back panel is simple and has nothing other than an on/off switch, input power and dual RCA line in.
Headphone Amplifier Audio Measurements
Here is our dashboard with unity gain (same output as input voltage):
First distortion product is below 100 dB and sets our SINAD to around that number which is good. It clears the hurdle for 16-bit audio which is the most common thing you will play. Turning up the volume improved the SINAD to 108 dB or so which is nice. Neither is a match for JDS Lab's Atom which clocks at 114 dB.
Signal to noise ratio at full volume was exceptional:
At 50 millivolt the performance is not class leading but still very good:
Frequency response was ruler flat (excellent):
Most important thing for headphone amplifier is distortion versus power. Let's start with a high, 300 Ohm load:
There is no clipping indicating more power could be had if you had a DAC with higher than nominal 2 volt used in the above test.
Switching to 33 ohm which emphasizes current delivery gets us this:
We hit a wall at nearly half a watt which should be plenty for most headphones but again, falls shy of more than 1 watt with the Atom. Distortion is lower than Schiit Magni 3 but there is less power was the case with 300 ohm load.
Output impedance test shows the truth about what the two headphone jacks are about:
That's right. The "low" headphone jack simply has a 150 ohm resistor inline with it. This will radically change the frequency response of most headphones so is not a good way to reduce output at all. The "high" jack is fine at 3 ohms.
EDIT:
Adding channel imbalance:
Excluding the final drop, the variation is +0.3 dB and -.05 dB. So pretty controlled.
Headphone Listening Tests
I tested the VMV VA2 with Sennheiser HD650. There was plenty of power here driving them to pretty loud levels in the high jack. Switching to low really messed things up so I don't recommend using that connector.
Performance was most excellent with Hifiman HE400i with lots of power, and excellent level of detail.
Conclusions
In a different era before the JDS Labs Atom came to market, this kind of performance would be excellent. Alas, the world has changed and these are no longer state-of-the-art measurements. That said, the subjective and objective performance is more than good enough. The hefty enclosure is definitely a huge step above the Atom although I dislike the volume control on VA2 as I noted.
So overall, a competent design from SMSL here and I can recommend it.
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