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SMSL D300 Review (Balanced DAC)

w1000i

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Didn't SMSL just release a high performing dac in this price point? I get confused they seem to release so many. Maybe I dreamt it. Filters seem average in this one, worthy of criticism?
There is HPC mode. I will try it deeply to see how it change the sound. I'm sure it will be difficult it possible.
 

Tangband

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The xmos is just the microprocessor used for USB interfacing, by itself you can't tell if a device will have decent or better jitter performance, it is just one piece in the processing/interfacing. Inherently it has no jitter specification. That's up to the device/DAC implementation.
True, but all reviews of dacs made by amirm that have the xu208 chip ( more than 10 ! ) shows, without exeption, similar excellent jitter measurements, so maybe many manufacturer uses the same implementation and programing of the xmos xu208 ? There is a pattern here that cant be ignored.:)

Amirm has also tested older dacs that dont use the xu208 chip but have less good USB solutions , and almost all of them shows very bad performance with the USB connection.

An example tested is here , a dac and earphone amplifier from 2005 that measures well with analog input but very bad with the USB input.

The SMSL D300 spec has this information about the xu208:

XMOS XU-208 USB Interface​

The USB-B input of the D300 embeds a XMOS XU-208 32bit chip. It allows the decoding of USB audio streams and offers a nice audio precision. Associated with the ROHM DAC, it allows the D300 to read high resolution streams, up to 32bit 768kHz PCM and native DSD512.
DF775387-16D1-45FF-93B3-F76AF67A1DC3.jpeg

The USB 8 kHz packet noise must be minimized to, and the xu208 is excellent at that.

”USB data transmission occurs in bursts every 125 μs. With the arrival of each such packet, the receiver will draw more power while creating a burst of high-frequency noise. The increased power draw can/will result in a corresponding dip in voltage. Without sufficient regulation, this dip will be seen by the DAC chip and end create an 8 kHz ripple in the output. Increased ground currents can also create voltage fluctuations at the DAC chip with the same effect. Another possibility is that aforementioned noise from the USB receiver gets into the analogue circuits through parasitic coupling where it is demodulated, again creating an 8 kHz tone.”

Read more here :
 
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DSJR

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£400 in UK (£399.99 inc VAT) with delivery early January if ordered from Amazon...
 

sseppala

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We lose a bit of performance as usual when switching to RCA out:
Isn't the perfomance loss of one bit (19 vs 18bit) equal to performance loss of 6dB. I see only a loss of 1dB :)

Thanks for the review Amir.
 

Vini darko

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Didn't SMSL just release a high performing dac in this price point? I get confused they seem to release so many. Maybe I dreamt it. Filters seem average in this one, worthy of criticism?
Yeah this new one is a step backwards too.
 

Lambda

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There is 2 output mode. One is fixed 4v the other variable reach 4.5V
No volume control with this DAC or what do you mean by fixed?
4 to 4.5 is also not a big difference. i wonder whats the difference between this modes.

Is it software limited to 4V? if so the 4V mode maybe has extra head room for filter and inter sample over?
 

PeteL

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The xmos is just the microprocessor used for USB interfacing, by itself you can't tell if a device will have decent or better jitter performance, it is just one piece in the processing/interfacing. Inherently it has no jitter specification. That's up to the device/DAC implementation.
Not really. The XMOS reference design, the included code, implement the USB audio class 2 interface, and that is what is 99% responsible for USB Jitter performance. In fact it should be immune to input jitter. After that yes the implementation may have small Intrinsic jitter depending of the quality of the internal clocking, but this is not really what the jitter test is testing anyway. In fact J-Test really has significance for spdif, or to see if there is an issue with USB, but what it really does is a simulation of worst case input Jitter and evaluate the DAC tolerance to it to retrieve and reject jitter noise. USB audio Class 2 by it's asynchronous nature should not be impacted by that. If it is there is a problem.
 
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Azathoth

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Wonder what the subjectivists will say about the "sound" of this DAC chip.
 

PeteL

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No volume control with this DAC or what do you mean by fixed?
4 to 4.5 is also not a big difference. i wonder whats the difference between this modes.

Is it software limited to 4V? if so the 4V mode maybe has extra head room for filter and inter sample over?
I think it means what it means? As many DACs you can choose to have, fixed output, for example if you use it with a preamp or an headphone amp with analog volume control. In this case It looks like its fixed at 4V, which "suggest" the performance is slightly preffered at a few dB less than 0 DBFS which is not uncommon. Then You have a mode with digital volume control, and if it's set to max (or I assume 0 dBFS if they haven't implement a Hybrid Digital and analog volume control) this output can reach 4.5 Volts. I haven't gone to the manual but that's how I translate the contributor statement based on how most DACS works.
 

Lambda

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so we are missing this test?
index.php

I assume now all measurements are made in the 4V at 0dBFS mode?

i wonder how performance would change at full volume.
 

PeteL

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so we are missing this test?
index.php

I assume now all measurements are made in the 4V at 0dBFS mode?

i wonder how performance would change at full volume.
Ha, it does indeed seem to go higher than what is specified by SMSL, strange. Or they specify this in a way I do not understand. Measurment at "Volume at 99" imply that Amir tested it in variable (or preamp) mode. Also this is a sweep by changing the generator level, not using the actual volume control but it's still odd.


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Tangband

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Not really. The XMOS reference design, the included code, implement the USB audio class 2 interface, and that is what is 99% responsible for USB Jitter performance. In fact it should be immune to input jitter. After that yes the implementation may have small Intrinsic jitter depending of the quality of the internal clocking, but this is not really what the jitter test is testing anyway. In fact J-Test really has significance for spdif, or to see if there is an issue with USB, but what it really does is a simulation of worst case input Jitter and evaluate the DAC tolerance to it to retrieve a reject jitter noise. USB audio Class 2 by it's asynchronous nature should not be impacted by that. If it is there is a problem.
Thanks for explaining . Here one can read more about xmos :
 

Transmaniacon

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This or the Topping D30 Pro? I’ve always owned Topping and have enjoyed them, but the SMSL units are sleek and the screen looks cool.
 
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