Toku points out that the upgrade VMV model will have digital inputs.
Hopefully it's not just an onboard DAC whose outputs are again digitized.
Toku points out that the upgrade VMV model will have digital inputs.
Agree the pricing is uncompetitive.
Nice Review, not competitive with Buckeye amp of similar power and much better measurements, and no buzzing coil issue. Yes, this could be connected to a DAC without volume control, the Buckeye could not.This is a review and detailed measurements of the SMSL SA400 switching desktop power (speaker) amplifier. It was sent to me by the company for testing and costs US $660.
The SA400 is a powerful amplifier yet it comes in the same compact SMSL package and UI you would find in their desktop amp:
View attachment 133641
Amplification is provided courtesy of ST Micro STa516BE. The marketing material for SA400 shows a digital feedback but I don't see that in the ST specs. I am not clear if this is an addition by SMSL or it is part of ST amplifier chip that they don't talk about. Either way the input to the amplifier is digital so even though we have analog inputs, they need to be digitized to be used internally:
View attachment 133642
A resonant LLC switching power supply provides the heft juice needed to drive this amplifier in a small package.
Bluetooth input is provided as well as a subwoofer output with low pass filter. In addition, tone controls are included using a dedicated JRC chip.
There is an informative temperature measurement you can turn on which I did as you see in the picture above. With normal music listening (one channel) the unit stay pretty cool. In testing however, the case got fairly warm and the display indicated 58 degrees C. I suggest not stacking anything on top of SA400.
One issue is a mechanical whine from an internal coil. I can hear it even when nothing is playing from about 1 foot or so. When testing at higher powers, this became much louder but when playing music, you won't be able to hear it most likely.
SMSL SA400 Measurements
There are three gain settings but performance is very similar between them. I adjusted high gain for 29 dB which is my standard (defaults to 30 dB):
View attachment 133644
View attachment 133645
View attachment 133646
For the rest of my testing I used the adjusted high gain for better comparison to other integrated amps adjusted the same way.
Distortion is around -90 dB but what pulls down SINAD is the rather high noise floor. This causes the overall ranking to be just slightly above average:
View attachment 133647
Indeed we can see the noise issue in our SNR measurements:
View attachment 133648
State of the art amplifiers get 16 bits of dynamic range at 5 watts so we are two bits short here. Even at full power you are adding noise to a 16 bit signal (you want your amp to be cleaner than the noise in the source). This, and the fact that there is no bandwidth above 20 kHz nukes any idea of playing high-res content:
View attachment 133649
Sure would have been nice to use an ADC that was running at 48 kHz, not 44 as it seems to be. Use of the ADC is likely the reason the noise floor is higher than it would be otherwise. We have seen this in AV receivers which likewise digitize their analog inputs (unless you put them in "native" mode).
There is some very good news though. The feedback for the amplifier is taken post filtering which means it can compensate for the interaction between that filter and the load. The above measurement shows actually two graphs: one at 8 ohm and the other, 4. Both land on top of each other showing the amp doesn't care which is great. We only see this in the best class D amps like Hypex Ncore and Purifi.
Crosstalk was very good but unpredictable:
View attachment 133650
You can see the normal trend in the other two amps (dashed lines).
Most important test for any amplifier is how much power we have and how much distortion and noise so let's look at that at 4 ohms:
View attachment 133652
This is a powerful little amp, producing nearly 500 watts of power especially if you allow some peaking:
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It complies with the spec which I think is 220 watts. Power naturally drops at 8 ohm but still healthy:
View attachment 133654
On our last test which is power versus distortion+noise at different frequencies. The output was quite unique:
View attachment 133656
I have not seen a power amplifier show this level of frequency independence. Yes, having only 20 kHz bandwidth helps but still, even linear amplifiers don't produce such dead straight and sameness the SA400 is producing. This is quite excellent.
Note that the the amp went into protection at both 20 kHz and 20 Hz in this sweep. Alas there was no indication on the display. I had to power cycle the unit to get it to work again.
SMSL SA400 Amplifier Listening Tests
Even though I listen to every headphone amplifier, I only do so rarely for power amplifiers. I decided to start doing listening tests with this amplifier which was a good thing. I used an Infinity 253 speaker for my testing. Despite driving only one channel, the SA400 drove the R253 with extreme authority and clarity. Tons of detail and dynamics with little else to wish for. Putting my ears next to the tweeter I could hear a slight hiss but a few inches away it would disappear. The sound was so enjoyable I am still listening to it as I type this!
Conclusions
SMSL brings us an interesting and unique power amplifier to us. Love the load independence and small packaging plus tons of power. Performance drops to average levels in some areas but nothing that appears to be faulty or poorly engineered. I guess my one reservation is the cost. I am not sure how much of this is temporary given the world order with component shortages, high shipping costs, etc. but to me, the better retail target would be $499. The warranty is short at 1 year as well. For DACs and such I am not worried about warranty much but for amps I do like to see longer warranty.
Overall, I am going to put the SMSL SA400 on my recommended list. It delivers tons of power with no weak points.
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As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
And boom goes the dynamite.SMSL passes the buck to Shenzenaudio for support with their products. This message was posted in one of the threads discussing issues with SMSL's products:
Dear Customer,
Thanks for your email.
Questions regarding the SMSL SU-9.
Kindly contact with SHENZHEN audio support team,
[email protected]
[email protected]
They are sole agent for this model and will give a reasonable suggestions.
Best regards
S.M.S.L Audio
I'm not sure why they bother sending the above message since @SHENZHENAUDIO do not reply to emails.
This is a review and detailed measurements of the SMSL SA400 switching desktop power (speaker) amplifier. It was sent to me by the company for testing and costs US $660.
Most important test for any amplifier is how much power we have and how much distortion and noise so let's look at that at 4 ohms:
View attachment 133652
On our last test which is power versus distortion+noise at different frequencies. The output was quite unique:
View attachment 133656
Overall, I am going to put the SMSL SA400 on my recommended list. It delivers tons of power with no weak points.
/
Overall, I am going to put the SMSL SA400 on my recommended list. It delivers tons of power with no weak points.
The Harman Citation uses the Axign modulator. That would be really interesting to get tested. I can't find a US price for this product yet, but it looks as if it will be much the same price, or cheaper than the SA400. Although it delivers less power than the SA400, it appears to offer a significantly more interesting value proposition, given it incorporates all the digital connectivity many demand.
The heat generated by the SA400 is at the same level as that of a vacuum tube amplifier. Maybe it can't be used very much during the midsummer season in Japan.should I keep it off? It's been idle 62C unused all day w/ ambient room temp at 23C. The case is pretty warm /hot
For the Tabebuia speakers,you can check them out at SMSL