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SMSL SA400 Review (Power Amplifier)

milosz

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Amirm, in your review you say "Either way the input to the amplifier is digital "

??? I don't see a digital audio input, though. Is there one?
 

Francis Vaughan

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GGroch

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Amirm, in your review you say "Either way the input to the amplifier is digital "
??? I don't see a digital audio input, though. Is there one?

The "either way" refers to whether the digital feedback is an addition by SMSL or it is part of ST amplifier chip. Only analog inputs, which are internally converted to digital for the digital amp. Toku points out that the upgrade VMV model will have digital inputs.
 

PeteL

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I have not tested it. This is what they show:

202105281517356584.jpg
So too high of a cutoff to be useful as a cross-over, just band limiting to save ressources and avoid de noisy stuff
 

Tks

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Still waiting on anyone releasing a competitor to the half decade ruling king of power amps: Benchmark's ABH2

All the prowess of DACs and Headphone amp performance belong to the Eastern manufactuerers. But power amps are just: Zzzz
 

PeteL

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Why would I buy this if instead I can get this Hypex based amp from buckeye ?

2 channel NC502MP, 2x500w @ 4ohm $649 shipped
2 channel NC252MP, 2x250w @ 4ohm $499 shipped
For safety regulations certified compliance I guess.
 

Billy Budapest

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Tabebuia trees are also called “Trumpet trees,” so maybe they meant to call the EQ setting “Trumpet” but there was some kind of mistranslation?
 

mdsimon2

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We already know. This is worse, appart from THD+N Vs Frequency.



Because they do need to sell M400 and SU-9 DACs.;)

Although THD+N vs frequency is more consistent on this, it is significantly worse overall than a NC252MP. Although I guess that is mostly due to higher noise in the SA400 and 45 kHz bandwidth of THD+N vs frequency measurements. For example at 5 watts worst frequency of SA400 is -55 dB while the NC252MP is -72 dB.

SA400
SMSL SA400 Power into 4 ohm versus frequency Measurements High Gain Integrated Amplifier.png


NC252MP
Buckeye Amplifier 3XNC252MP Measurements Power into 4 ohm vs distortion and frequency.png


Michael
 

respice finem

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Thanks a lot @Amir for the review.
At this price, I think digital in and headphone out would be nice to have.
 

NTK

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@Francis Vaughan Thanks for this product brief. You're right AX5689 ADC part provides the analog inputs. I keep thinking that STA516BE is the limiting chip here (@amirm review shows high noise), something like this https://www.ti.com/product/TAS5612LA would have been better...
AudioXpress has an 2017 article on the AX5689. It has a few performance charts from Axign with its chip paired with ST516B, TAS5342A and TAS5624A, but for lower power output (~50 W @ 4Ω). The Axign THD+N numbers looked to be about 10 dB better those Amir measured, and seemed to be noise related. (Again, the Axign implementations were lower power, so not exactly apple-to-apple.)
https://audioxpress.com/files/attachment/2659

Interestingly, according to the article, the AX5689 + TAS5342A performed better than the AX5689 + TAS5624A, when the AX5689 didn't have the "wrestle with the internal feedback loop of the TAS5624A". So, it may actually perform worse with the TAS5612A that has internal feedback. (The performances of ST516B and TAS5342A were identical in the article.)
 

bud947

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Interestingly, according to the article, the AX5689 + TAS5342A performed better than the AX5689 + TAS5624A, when the AX5689 didn't have the "wrestle with the internal feedback loop of the TAS5624A". So, it may actually perform worse with the TAS5612A that has internal feedback. (The performances of ST516B and TAS5342A were identical in the article.)
Thanks for this article. Taking in account this information I can understand why they choose the ST516BE but still we see that the chip is having a hard time controlling the noise of the output stage, may be a dual ST516BE would have done the trick (the SMLS dual MA12070 is way much better than the single chip version) or an infineon output chip like the IRS20965S or the one used here https://www.digikey.se/catalog/en/partgroup/irs20957-evaluation-board/1599

To me it's like they went with the cheapest reference design for AX5689 instead of testing with differents output stage and opting for the best
 

Kachda

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Amirm, in your review you say "Either way the input to the amplifier is digital "

??? I don't see a digital audio input, though. Is there one?
None. though it seems like a missed opportunity, not having an ADC at the begining may have reduced the noise floor maybe ?
 

Soniclife

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I don't get why they are so close to making an integrated amp with multiple inputs, but didn't. Also it can low pass the sub out, which is good, but can it high pass the mains? Without the high pass it's almost useless, and it's a rare subwoofer that cannot low pass itself.
 
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