Sabaj D5 vs. SMSL M500 vs. Topping DX7 Pro: measurement comparison

[Shoaibexpert]

Are all 3 linear against different frequencies?

 

[daftcombo]

Does lowering the digital volume on the DAC affects the sound quality?

Not audibly.

 

[MediumRare]

Does lowering the digital volume on the DAC affects the sound quality?

Yes it does: look at the power to distortion charts and you’ll see noise rejection is more important at lower output levels.

BUT: it is completely inaudible with these DACs at -70dB. Most people can barely hear a full 0 dB signal at -70 dB so you can’t possibly hear any distortion there.

 

[NielsMayer]

i don't think there's any reason to believe that the m500 is pseudo-balanced, and performance increases measurably via the balanced outputs.

IMHO, the opposite is true. If the performance increase is 'too large' it might indicate fake balanced is used and that you're seeing 1/2 the noise and distortion from the use of 1/2 the op-amps on outputs. IMHO in "real balanced" the performance increase in the use of balanced connection (all of those improvements reside in the receiving end differential input, not the output of unit being tested) is partially negated by the extra noise and distortion produced by the second op amp driving the (-) line. So you might end up seeing a 1-3dB improvement in "real balanced" vs a 4-6dB improvement in fake balanced.

Furthermore, unless the balanced op amps are exactly the same in linearity, amplification, bandwidth, slew-rate, etc additional distortions are produced by real world mismatches in the output op-amps and components which need to be a precise mirror image of each other in order to truly be electrically balanced. Let's say two 5% resistors used in feedback circuit. worst case scenario would give a 10% mismatch between outputs just from spec-compliant variations in the resistor values used. I dont see any 0.1% tolerance resistors used in any of the real balanced designs, so without hand-tuning you could end up with a really crappy "real balanced" output that isn't actually balanced at all in production and whose noise and nonlinearity from the second op amp are significantly worse than the resistor they'd replace in an "impedance balanced" architecture.

 

[Shoaibexpert]

So let me ask the question, money and MQA aside aside...which DAC is technically Superior: the M500 or the Topping DX7PRO, noting that the M500 beats the Topping DX7PRO in Dynamic range, linearity and THD+Noise VS Frequency stats? Thanks

 

[Shoaibexpert]

IMHO, the opposite is true. If the performance increase is 'too large' it might indicate fake balanced is used and that you're seeing 1/2 the noise and distortion from the use of 1/2 the op-amps on outputs. IMHO in "real balanced" the performance increase in the use of balanced connection (all of those improvements reside in the receiving end differential input, not the output of unit being tested) is partially negated by the extra noise and distortion produced by the second op amp driving the (-) line. So you might end up seeing a 1-3dB improvement in "real balanced" vs a 4-6dB improvement in fake balanced.

Furthermore, unless the balanced op amps are exactly the same in linearity, amplification, bandwidth, slew-rate, etc additional distortions are produced by real world mismatches in the output op-amps and components which need to be a precise mirror image of each other in order to truly be electrically balanced. Let's say two 5% resistors used in feedback circuit. worst case scenario would give a 10% mismatch between outputs just from spec-compliant variations in the resistor values used. I dont see any 0.1% tolerance resistors used in any of the real balanced designs, so without hand-tuning you could end up with a really crappy "real balanced" output that isn't actually balanced at all in production and whose noise and nonlinearity from the second op amp are significantly worse than the resistor they'd replace in an "impedance balanced" architecture.

Just to confirm, you're saying the M500 maybe fake balanced whilst Topping DX7PRO maybe true balanced?

 

[RickSanchez]

So let me ask the question, money and MQA aside aside...which DAC is technically Superior: the M500 or the Topping DX7PRO, noting that the M500 beats the Topping DX7PRO in Dynamic range, linearity and THD+Noise VS Frequency stats? Thanks

Just the DAC portion? None of these 3 are "superior" when compared to each other. The measurements show that the levels of noise and distortion are in the inaudible range for all 3; you would not be able to tell them apart in a level-matched, blind listening test. So if evaluating just the DAC portion you should focus on what matters to you in terms of price, features, build quality/warranty/customer service, aesthetics, etc.

If you're also considering these for the headphone amp the same things (price, features, etc.) also apply. For instance, the M500 does not have an XLR headphone out if that's important to you. After that you need to consider if the amps will be a good match for your headphones, specifically in terms of output impedance and power. For example: the 6.2 ohm output impedance of the DX7 Pro will be a concern for some people based on the impedance of the headphones they own or plan to buy.

 

[Scriba]

I will probably get the DT 1990 (250 ohms) and looking for a DAC/Amp combo which is neutral in the sound and can make use from the advantages which the HP offers (mainly: clarity, precise imaging, separation). Which one could you recommend for the DT 1990?

 

[VintageFlanker]

I will probably get the DT 1990 (250 ohms) and looking for a DAC/Amp combo which is neutral in the sound and can make use from the advantages which the HP offers (mainly: clarity, precise imaging, separation). Which one could you recommend for the DT 1990?

Each one of them is neutral. I would go for the DX7 PRO which provide more power at all loads though its 1/4 output (High gain).

Ps: however, the DT1990 with its massive peak at 8-10Khz is not neutral.

 

[Scriba]

Each one of them is neutral. I would go for the DX7 PRO which provide most power at all loads though its 1/4 output (High gain).

Ps: however, the DT1990 with its massive peak at 8-10Khz is not neutral.

All right, thanks for the suggestion!

I know about the 8-10Khz peak. With neutral I meant the DAC/amp shouldn't make the sound more warm as the clarity and imaging get's a bit more worse (that's at least what i read).

 

[VintageFlanker]

With neutral I meant the DAC/amp shouldn't make the sound more warm as the clarity and imaging get's a bit more worse (that's at least what i read).

This won't happen once you're not power limited with a distortion-free output. Also, I wouldn't bother about the DX7PRO impedance with the DT1990.

 

[Shoaibexpert]

Just the DAC portion? None of these 3 are "superior" when compared to each other. The measurements show that the levels of noise and distortion are in the inaudible range for all 3; you would not be able to tell them apart in a level-matched, blind listening test. So if evaluating just the DAC portion you should focus on what matters to you in terms of price, features, build quality/warranty/customer service, aesthetics, etc.

If you're also considering these for the headphone amp the same things (price, features, etc.) also apply. For instance, the M500 does not have an XLR headphone out if that's important to you. After that you need to consider if the amps will be a good match for your headphones, specifically in terms of output impedance and power. For example: the 6.2 ohm output impedance of the DX7 Pro will be a concern for some people based on the impedance of the headphones they own or plan to buy.

Thanks for that. Got the SMSL M500 today at deep discount! I saw where the discussion was leading to so I made my choice accordingly

 

[RickSanchez]

In regards to my note about the filters/FFT measurements, member @Bjoran has provided some new info. The original manual for the DX7 Pro -- which is what Amir used -- listed the filters in the wrong order. This has now been corrected by Topping and there is a new manual.

I don't think Amir has the time to fix the measurement screenshot so please review the original FFT measurements carefully for the DX7 Pro and make the corrections on your own using the new manual ... if that's important to you.

The order of the seven filters in the review of the DX7 Pro has been questioned. So, I sent an email to the Topping Support and asked them if the order of filters is correct in the manual for the DX7 Pro. They answered very quickly and the answer was that the order (1 to 7) in the manual is incorrect.

And now I can see that they have uploaded a revised manual for the DX7 Pro. It can be downloaded from the same place as before: http://www.tpdz.net/support.html

The order of the seven filters is now the same as for the DX7s. Amir has done a correct measurement but unfortunately the texts he got from the manual were in the wrong order.

 

[MediumRare]

In regards to my note about the filters/FFT measurements, member @Bjoran has provided some new info. The original manual for the DX7 Pro -- which is what Amir used -- listed the filters in the wrong order. This has now been corrected by Topping and there is a new manual.

How can I tell if I have new manual? Is the one online correct?

 

[RickSanchez]

How can I tell if I have new manual? Is the one online correct?

I believe the online manual is correct. I downloaded the full .zip file and unpacked it to view the manual. However, I don’t have a previous version to compare it to in order to see what — if any — changes have been made. It might be a good question for Topping support to verify.

 

[Scriba]

the real questions seems to be why buy any of this devices if you can buy the SMSL SP200 THX amp and some decent dac (SMSL M200 in ~january) for the same or even less money.

 

[Veri]

the real questions seems to be why buy any of this devices if you can buy the SMSL SP200 THX amp and some decent dac (SMSL M200 in ~january) for the same or even less money.

Some people prefer an all-in-one, especially in terms of desk space.
And some will buy M500 for MQA..

 

[RickSanchez]

Some people prefer an all-in-one, especially in terms of desk space.
And some will buy M500 for MQA..

Adding to that:

1. You can save a few dollars by not having to buy XLR interconnects between the DAC and amp (if you have ground loop issues).
2. Channel balance is typically perfect for combo DAC+amps because they can use the DAC for digital volume control. Tough to get that with most stand-alone amps. As Amir states: "No headphone amplifier using analog volume control comes remotely close to this kind of performance."

 

[Scriba]

1. you can use just rca cables right. If you use the dx7 pro only (without seperate amp) you don't have balanced connection aswell
2. Can't you use in this case just the volume knob of the DAC and set the amp to full volume?

 

[SIY]

Just to confirm, you're saying the M500 maybe fake balanced whilst Topping DX7PRO maybe true balanced?

No, @NielsMayer is incorrect in his understanding of what "balanced" means. If source impedances are the same for + and -, an output is balanced, regardless of voltage measurements to some other arbitrary point. This is a very common error.