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SMSL SA400 Review (Power Amplifier)

Helicopter

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#62
Thanks Amir. This looks like a sweet little amp. Agree the pricing is uncompetitive. Something closer to $400 would be a lot more palatable. Loxjie A30 is a better buy for anyone who doesn't need the extra power, and NC252MP based amps are probably better for most who do need the power. Agree with prior comment, I would just love to see what Topping can do in an amp like this.
 

AndreaT

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#65
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:

View attachment 133653

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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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.
 

Xyrium

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#66
Meh, as suggested by others, even a low end Hypex solution takes this thing on, perhaps even Icepower. The SNR is borderline terrible due to the noise, and though the sub output, if filtered, is really nice, I'm not feeling it. It seems like a confusing proposition, given it's compact design, I keep thinking their market is desktop, but the price for performance isn't there for such an application, IMHO. That sub output though, smart for sure....
 

don'ttrustauthority

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#67
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.
And boom goes the dynamite.
 

B4ICU

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#68
Hi Amir
The Spec of the manufacturer nor the manual, do not specify the DF. Could you please be kind to measure it?
Thanks
 

Francis Vaughan

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#69
Axign have a patent on their modulator design. It makes for very interesting reading.
https://patents.justia.com/patent/10659028
They announced their first product the month after the patent was granted.

Although this amplifier isn’t it, I have a feeling we are about to see the first significant competition for Hypex. It is no longer a matter of a full Hypex module, the important bit is now a single chip solution. Moreover it is a single chip for 8 channels solution.

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.

Although we are quite a bit short of the fabled game changing affordable high power, high performance amp, I do suspect progress towards it has taken another step.
 
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pma

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#70
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.
In my view, this is a poor amplifier at high price of $660. I would never recommend it to anyone. Big differences in distortion of the two channels indicate to poor engineering design skills. THD+N with 45kHz measuring BW gave a very poor result. "Consistent" means masked by something bad. I am missing HF measurement to see carrier frequency residuals and HF noise. I am afraid that a product like this shows audio future.
 

bloodshoteyed

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#71
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.
not sure why the limited availability, even in Europe only their Norway local site has it listed (and if i remember correctly, there was a question about US release dates with an answer that it's not planned atm)
availabilty in stores is also hit & miss, with prices ranging 510-600€
 
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#73
I wonder if the "resonant LLC switching power supply" is the same or similar to what's used in the SMSL DA-9 amplifier? That amp destroys my powerline ethernet throughput, dropping throughput by about 75%...
 
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#74
We in there
41AF36A6-9D91-4826-B19E-656BB827694F.jpeg


Edit 1:
C2EB5B10-242F-4B93-A1C9-B69E36F00298.jpeg
There’s too much power for me xD I listen comfortably 5-15 lowest gain preset and it can go all the way up to 80 w/ 3 gain levels. I guess that’s the power of balanced too. This is my first balanced input set.

klipch rp600m, ifi neo idsd, balanced xlr

I also have a da-9 coming in a couple days

Edit 2:
7C7EF402-A9A9-4999-8787-D2F64CD3D411.jpeg
i watched a movie and constantly increased volume up to now 25. The case is hot and reads 66 Celsius

Edit 3: I like it soo far. It's silent and there is no noise. I keep it on my desk and i sit 2 feet away from it. I dont hear coil whine(someone mentioned slightly audible coil whine??). I ran it through MQA and DSD it sounds better than SA300. It could just be going to balanced. We'll see when the da-9 comes in a couple days.

What i dont like: it's warm/hot all the time. When idle it's reading 62 Celsius. I upped the height with rubber feet to let it breath which helped a little. The fan doesnt kick on until 65C ?? Altho it never got that hot for me to hear or notice the fan was on.
 
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#75
Why does this amp cost several hundred more than the DA9? I'm thinking the DA9 is the way better value here. What am I missing?
 
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#76
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
 

Toku

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#77
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
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.
 
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#78
From SMSL for adjusting fan operating temp:

When the SA400 leaves the factory, the engineer sets the fan work on 65℃ Celsius, and you can set the fan work temperature. Please follow the steps below to adjust the opening temperature of the SA400 fan :

1. Enter the menu and set the "SUB GAIN" to the lowest
2. Return to the main interface and turn the volume to the lowest
3. Continue to turn down the volume until the setting interface appears
4. Press the knob button to select the "fan on temp" option, and press the knob or the remote control up and down buttons to adjust the fan on temperature
5. Press and hold the knob to exit

Our testing department has tested the product. They set the fan's working temperature to 48°C and kept it working for 2 hours, keeping the temperature at 47~48°C. You can adjust the temperature that suits you according to the steps we provide above.
 

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