Loxjie D40 Pro DAC & HP Amp Review

[jkim]

I’d like to know the differences between the LOXJIE D40 Pro and the LOXJIE D60. And in terms of headphone amplification, which of the two could better drive HD660 S2? Many thanks for your answers.

I hope you have taken the following message clearly after asking quite a few similar questions here at ASR:

A properly designed desktop DAC/headphone amp combination device will NOT make the HD660 S2 sound any different from another properly designed device.

If you really want your headphones to sound different, then develop your own EQ setting and/or purchase another set of headphones.

EDIT. AFAIK there is no major difference b/w LOXJIE D40 Pro and D60 except for their appearance. Essentially, the D60 is a minor facelift of the D40 Pro.

 

[Berwhale]

To claim that no desktop DAC — whether a modest SMSL or an RME — will make any difference strikes me as not only peculiar… but intellectually dishonest.

A DAC and DAC integrated with a headphone amplifier are different devices.

The claim, backed up by objective measurement and blind testing, is that no desktop DAC that has been measured to be audibly transparent, will sound any different from any other DAC that has been measured to be audibly transparent. This is for a pure DAC and assumes that the DAC is being fed a signal which audibly transparent (e.g. CD quality) and that the DAC output signal is the ballpark of 2 volts for a single ended line output (RCA) or 4 volts for a balanced connection.

When it comes to a DAC paired with a headphone amplifier, then things are little more complicated. This is because the amp interacts with the headphones and attributes of the headphone such as very low impedance and or very high sensitivity could cause audible issues, even though the amp is measured to be transparent with less extreme loads (e.g. clipping at high volume with very low impedance headphones, or audible noise floor with high sensitivity IEMs)

Given that the HD 660 S2 have moderate impedance and sensitivity, then the potential issues above are unlikely (but not impossible) to be a concern for pretty much any of the desktop DAC & HP Amps that Amir has measured and recommended.

Here is an excellent thread summarising what is and isn't audible when it comes to DAC and amplifier measurements.... https://www.audiosciencereview.com/...-thresholds-of-amp-and-dac-measurements.5734/

P.S. I would take the D60 over the D40 Pro, simply because of the nicer display and chassis. The manufacturers measured performance is almost identical for both, which is not surprising given they appear to share almost identical circuitry.

 

[ArthurStein13]

A DAC and DAC integrated with a headphone amplifier are different devices.

The claim, backed up by objective measurement and blind testing, is that no desktop DAC that has been measured to be audibly transparent, will sound any different from any other DAC that has been measured to be audibly transparent. This is for a pure DAC and assumes that the DAC is being fed a signal which audibly transparent (e.g. CD quality) and that the DAC output signal is the ballpark of 2 volts for a single ended line output (RCA) or 4 volts for a balanced connection.

When it comes to a DAC paired with a headphone amplifier, then things are little more complicated. This is because the amp interacts with the headphones and attributes of the headphone such as very low impedance and or very high sensitivity could cause audible issues, even though the amp is measured to be transparent with less extreme loads (e.g. clipping at high volume with very low impedance headphones, or audible noise floor with high sensitivity IEMs)

Given that the HD 660 S2 have moderate impedance and sensitivity, then the potential issues above are unlikely (but not impossible) to be a concern for pretty much any of the desktop DAC & HP Amps that Amir has measured and recommended.

Here is an excellent thread summarising what is and isn't audible when it comes to DAC and amplifier measurements.... https://www.audiosciencereview.com/...-thresholds-of-amp-and-dac-measurements.5734/

P.S. I would take the D60 over the D40 Pro, simply because of the nicer display and chassis. The manufacturers measured performance is almost identical for both, which is not surprising given they appear to share almost identical circuitry.

Thank you very much for your message—it was both high in quality and full of insightful information.

You mentioned the D40 and D60, but I’d also be very interested to hear your thoughts on the DO400 compared to the MDA1. Some say there’s barely any audible difference between the two—would you agree? Lastly, do you happen to have any impressions or feedback on the JC Acoustics UDP5 and UDP6?

Thanks again for your time and expertise.

 

[Berwhale]

Thank you very much for your message—it was both high in quality and full of insightful information.

You mentioned the D40 and D60, but I’d also be very interested to hear your thoughts on the DO400 compared to the MDA1. Some say there’s barely any audible difference between the two—would you agree? Lastly, do you happen to have any impressions or feedback on the JC Acoustics UDP5 and UDP6?

Thanks again for your time and expertise.

I think that the Loxjie D40 Pro, D60 and SMSL DO400 are all essentially the same device (my understanding is that SMSL and Loxjie are 'sister' brands). Try looking at the back panels of these devices; apart from the font used for the labels, they are indistinguishable. I would be happy with any of them in my setup, although the chassis are a little wide for my particular needs.

The SMSL RAW-MDA 1 is a different device. One noticeable difference is that it only has a single ended headphone* output (it has a 'balanced' capable 4.4mm socket, but this is wired to a single ended amp). A balanced HP output can potentially provide more power than a singled ended output. However, this would only be useful if you have particularly insensitive headphones. The HD 660 S2 are not insensitive and do not require a lot of power to drive to hearing damaging levels.

*(The RAW-MDA1 does have balanced XLR outputs on the back, these can be important for solving or avoiding ground loop noise from connected monitors, especially if the DAC/Amp is connected to a PC).

In 'real world' use I would expect all of these devices to perform well and drive the HD 660 S2 to more than acceptable levels. On the other hand, if you do plan to dabble in other headphones and maybe play around with parametric EQ (PEQ), then it may be wise to furnish yourself with one of the devices with a balanced HP Amp.

My understanding is that the SMSL 'RAW' devices are built specifically for Shenzhen Audio specifications. In this sense, the SMSL RAW-MDA 1 is the 'spiritual successor' to the Topping x ShenzhenAudio EX5 DAC/Amp that I have sitting on my desk. I use my HD 660 S with the EX5 and they go more than loud enough for me. The EX5 has less power than the RAW-MDA1 and I am applying PEQ to boost the bass on the HD 660 S. Boosting the bass, requires me to apply negative pre-amp the signal sent from my PC to avoid clipping. This means that I have to turn volume on the EX5 up a little higher than if I wasn't applying PEQ.

I certainly don't need to upgrade my EX5 from a performance perspective, but I might buy the Topping DX5 II for the nicer looks and fancy display (if it ever comes out!).... https://www.audiosciencereview.com/forum/index.php?threads/topping-dx5-ii.60996/

 

[jkim]

Thank you very much for your message—it was both high in quality and full of insightful information.

You mentioned the D40 and D60, but I’d also be very interested to hear your thoughts on the DO400 compared to the MDA1. Some say there’s barely any audible difference between the two—would you agree? Lastly, do you happen to have any impressions or feedback on the JC Acoustics UDP5 and UDP6?

Thanks again for your time and expertise.

Sorry if my earlier post sounded irritated. I must have been in a bad mood.

When I say a "properly designed" desktop DAC/HP amp combo device, it implies a few things:

• The DAC component should perform well with respect to linear distortion (i.e., frequency response), nonlinear distortion (THD, IMD, etc.), and noise by modern standards.
• The headphone amp stage should also perform well in the same regards (plus low output impedance).
• The power of the headphone amp must be above a certain level so it may be rightly called a desktop device.

Pretty much any DAC/HP amp desktop combo device from SMSL, Topping, or another reputable brand will meet these criteria. In that sense, you will hear no difference between these devices through the Sennheiser HD 660 S2.

 

[ArthurStein13]

I think that the Loxjie D40 Pro, D60 and SMSL DO400 are all essentially the same device (my understanding is that SMSL and Loxjie are 'sister' brands). Try looking at the back panels of these devices; apart from the font used for the labels, they are indistinguishable. I would be happy with any of them in my setup, although the chassis are a little wide for my particular needs.

The SMSL RAW-MDA 1 is a different device. One noticeable difference is that it only has a single ended headphone* output (it has a 'balanced' capable 4.4mm socket, but this is wired to a single ended amp). A balanced HP output can potentially provide more power than a singled ended output. However, this would only be useful if you have particularly insensitive headphones. The HD 660 S2 are not insensitive and do not require a lot of power to drive to hearing damaging levels.

*(The RAW-MDA1 does have balanced XLR outputs on the back, these can be important for solving or avoiding ground loop noise from connected monitors, especially if the DAC/Amp is connected to a PC).

In 'real world' use I would expect all of these devices to perform well and drive the HD 660 S2 to more than acceptable levels. On the other hand, if you do plan to dabble in other headphones and maybe play around with parametric EQ (PEQ), then it may be wise to furnish yourself with one of the devices with a balanced HP Amp.

My understanding is that the SMSL 'RAW' devices are built specifically for Shenzhen Audio specifications. In this sense, the SMSL RAW-MDA 1 is the 'spiritual successor' to the Topping x ShenzhenAudio EX5 DAC/Amp that I have sitting on my desk. I use my HD 660 S with the EX5 and they go more than loud enough for me. The EX5 has less power than the RAW-MDA1 and I am applying PEQ to boost the bass on the HD 660 S. Boosting the bass, requires me to apply negative pre-amp the signal sent from my PC to avoid clipping. This means that I have to turn volume on the EX5 up a little higher than if I wasn't applying PEQ.

I certainly don't need to upgrade my EX5 from a performance perspective, but I might buy the Topping DX5 II for the nicer looks and fancy display (if it ever comes out!).... https://www.audiosciencereview.com/forum/index.php?threads/topping-dx5-ii.60996/

Thank you so much for your message — remarkably clear and generous, as few are on this forum, with the notable exception of Roland68, whose insights were just as valuable. Reading your reply helped me better grasp some technical points I had long struggled to understand.

May I ask whether, in your opinion, there’s a real improvement in sound quality when moving from the MDA1 to the DO400 or DO60? Also, I have the opportunity to buy a used RME ADI-2 DAC FS for €750, and I’d love to know whether you think its headphone amplification section would be a good match for the Sennheiser HD 660S2.

Thank you again for your time and the precision of your advice.

 

[jkim]

*(The RAW-MDA1 does have balanced XLR outputs on the back, these can be important for solving or avoiding ground loop noise from connected monitors, especially if the DAC/Amp is connected to a PC).

Not sure what you mean by this. Do you mean balanced line-level outputs will be useful when there's ground loop noise from an external device, like monitors or an amp, connected to the line-level outputs? If so, note that balanced line-level connection itself cannot resolve ground loop noise.

In 'real world' use I would expect all of these devices to perform well and drive the HD 660 S2 to more than acceptable levels. On the other hand, if you do plan to dabble in other headphones and maybe play around with parametric EQ (PEQ), then it may be wise to furnish yourself with one of the devices with a balanced HP Amp.

Balanced HP amp design is not superior to an unbalanced headphone amp assuming that both provides the same power---this article is a nice write-up on the topic. Nonetheless, we should admit that we access higher power through balanced HP amps in many devices on the market.

 

[ArthurStein13]

Désolé si mon message précédent a semblé irrité. Je devais être de mauvaise humeur.

Please don’t worry. My many questions simply reflect the hesitation of someone still learning — I understand they might be tiring, and I offer my apologies if my messages came across as overly persistent.

 

[jkim]

May I ask whether, in your opinion, there’s a real improvement in sound quality when moving from the MDA1 to the DO400 or DO60? Also, I have the opportunity to buy a used RME ADI-2 DAC FS for €750, and I’d love to know whether you think its headphone amplification section would be a good match for the Sennheiser HD 660S2.

If you mean a "real, audible improvement in sound quality," no, there should be none when moving from the RAW-MDA 1 to the DO400 or DO600.

The RME ADI-2 DAC FS supports some useful DSP effects, such as on-device PEQ, loudness control and cross-feed, which are highly valued by quite a few members here.

EDIT. I also own the RME ADI-2 DAC FS and quite a few DACs & HP amps offering the state-of-the art measured performance. With DSP effects turned off, I cannot hear any difference between these devices.

 

[jkim]

Thank you sincerely for this reply — it stands out as the clearest, most straightforward, and thus most reassuring answer I’ve received so far on this forum. Thanks to your input, I now know I won’t be buying the DO400, the DO60, or the Loxjie D40 Pro, and I may well reconsider the MDA1 for the time being — at least until the anticipated Topping DX5 II is released.

Sounds great.

That said, I’d like to return with one final point of uncertainty: is the headphone amplification section of the RME ADI-2 DAC FS truly capable of properly driving the Sennheiser HD 660S2 ? Many thanks in advance for your insights.

The HP amp section of the RME ADI-2 DAC FS is extremely capable. It provides as powerful, transparent amplification as the RAW-MDA 1.

 

[ArthurStein13]

Sounds great.


The HP amp section of the RME ADI-2 DAC FS is extremely capable. It provides as powerful, transparent amplification as the RAW-MDA 1.

Many thanks for your replies: clear, to the point, and — most importantly — free from the usual flood of mysterious specs (dB levels, impedance, and other such arcana) that had remained quite obscure to me. Thanks to you, my options are finally narrowed down: it’ll be either the MDA1 or the RME ADI-2. I believe I can now leave this forum in peace… for a few months. Thank you, truly!

 

[Berwhale]

Not sure what you mean by this. Do you mean balanced line-level outputs will be useful when there's ground loop noise from an external device, like monitors or an amp, connected to the line-level outputs? If so, note that balanced line-level connection itself cannot resolve ground loop noise.

With a PC in the chain, it's possible for noise to be transmitted from the PC, down the USB shield and into the unbalanced signal ground and through to your monitors. I had exactly this situation with an unbalanced Topping stack (D50s & A50s) when I upgraded from monitors without a safety ground (Tannoy Reveal 402) to monitors with a safety ground (iLoud MTM). The noise was very audible as soon as the MTMs were powered on and made them unusable.

I was able to solve the issue with the Topping stack by optically isolating the PC from the D50s by using Toslink or by inserting a cheap ADUM3160 USB isolator. Ultimately, I replaced the D50s/A50s stack with a Topping EX5 which has a balanced output which is isolated from any chassis or safety ground, so doesn't provide a path for PC noise to travel to the MTMs.

Balanced HP amp design is not superior to an unbalanced headphone amp assuming that both provides the same power---this article is a nice write-up on the topic. Nonetheless, we should admit that we access higher power through balanced HP amps in many devices on the market.

Yes, I know. From a pure power perspective, the switch from the A50s to the EX5 above was a backwards step. However, none of my headphones are particularly difficult to drive and the reduction in power makes no difference in everyday use (and I still have the D50s/A50s by my bedside should I ever require more oomph!).

 

[Berwhale]

Many thanks for your replies: clear, to the point, and — most importantly — free from the usual flood of mysterious specs (dB levels, impedance, and other such arcana) that had remained quite obscure to me. Thanks to you, my options are finally narrowed down: it’ll be either the MDA1 or the RME ADI-2. I believe I can now leave this forum in peace… for a few months. Thank you, truly!

Happy DAC/HP Amp hunting!

 

[jkim]

Ultimately, I replaced the D50s/A50s stack with a Topping EX5 which has a balanced output which is isolated from any chassis or safety ground, so doesn't provide a path for PC noise to travel to the MTMs.

Signal ground is usually not isolated from safety (i.e., mains) ground unless there is a separate ground lift switch (ideally on the downstream device). I believe in your case the ground loop noise must have been significantly reduced below an audible level thanks to the balanced connection's common mode rejection (CMR).

But in some cases CMR is not enough to resolve ground loop noise.

 

[Berwhale]

Signal ground is usually not isolated from safety (i.e., mains) ground unless there is a separate ground lift switch (ideally on the downstream device). I believe in your case the ground loop noise must have been significantly reduced below an audible level thanks to the balanced connection's common mode rejection (CMR).

But in some cases CMR is not enough to resolve ground loop noise.

I'll let our host explain it for you... https://www.audiosciencereview.com/forum/index.php?threads/understanding-balanced-audio-video.22144/

 

[jkim]

I'll let our host explain it for you... https://www.audiosciencereview.com/forum/index.php?threads/understanding-balanced-audio-video.22144/

Again, balanced connection does not break or completely "eliminate" a ground loop. It can only mitigate the problem which can be effective enough in many cases. Amir knows how it works. He simply did not go into further details (i.e., specific points that I made above) in that video.

EDIT. I am sorry if I gave you an impression that I make nit-picking comments. In hindsight, we're not talking about different things with respect to practical effects. I just wanted to point out a misconception when you said, "a balanced output which is isolated from any chassis or safety ground, so doesn't provide a path for PC noise to travel to the MTMs," because that is not how it works. Balanced connection does not literally isolate signals from safety ground unless the ground is deliberately lifted. Common mode rejection is the main factor in that case.

 

[ziggurcat]

To anyone who has the D40 Pro or the D60:

How is it? Are there any issues (specifically, are there ticks/pops any time audio is paused/songs skipped, when a system sound plays, or input switching, etc...)? I just tried out the SMSL RAW MDA-1, and those are the issues that lead me to return it (unfortunately... because it sounded fantastic). Use case would be in a Mac Mini M1 Desktop system.

I am unable to find a local online retailer (Amazon Canada does not have the D40 Pro, but it has the D60). I think I can order both from Hifi Express if necessary, Amazon is just so much easier to return if it ends up not working out.

 

[zWo3]

To anyone who has the D40 Pro or the D60:

How is it? Are there any issues (specifically, are there ticks/pops any time audio is paused/songs skipped, when a system sound plays, or input switching, etc...)? I just tried out the SMSL RAW MDA-1, and those are the issues that lead me to return it (unfortunately... because it sounded fantastic). Use case would be in a Mac Mini M1 Desktop system.

I am unable to find a local online retailer (Amazon Canada does not have the D40 Pro, but it has the D60). I think I can order both from Hifi Express if necessary, Amazon is just so much easier to return if it ends up not working out.

I have the Loxjie D40 Pro and so far I'm actually very happy with it, the brilliance is great and the workmanship is good. The only thing that annoys me is that from time to time there are USB problems in the sense of I start the computer + speakers own Wavemaster Two Pro speakers + mivoc Hype 10 G2 subwoofer that at every start it only shows 44.1 Hz but I have set 192 Hz in Windows and then it cracks terribly and makes massive noises that are really very unpleasant. But as soon as I start an audio source everything is fine and the sound is really wonderful I would actually be interested in the D60 because it has a nicer display, but I doubt whether it sounds better. Also via my headphones Hifiman Arya Stealth + Sundara + Beyer Dynamic 1990 Pro superb sound

 

[ziggurcat]

I have the Loxjie D40 Pro and so far I'm actually very happy with it, the brilliance is great and the workmanship is good. The only thing that annoys me is that from time to time there are USB problems in the sense of I start the computer + speakers own Wavemaster Two Pro speakers + mivoc Hype 10 G2 subwoofer that at every start it only shows 44.1 Hz but I have set 192 Hz in Windows and then it cracks terribly and makes massive noises that are really very unpleasant. But as soon as I start an audio source everything is fine and the sound is really wonderful I would actually be interested in the D60 because it has a nicer display, but I doubt whether it sounds better. Also via my headphones Hifiman Arya Stealth + Sundara + Beyer Dynamic 1990 Pro superb sound

Gotta say that the issues you mentioned don't instil me with a lot of confidence. I think the Topping DX5 II is pretty close to being released, so I might wait for that instead since I know Topping gear decently okay, and I haven't had any of those types of problems with any of their gear.

 

[jmdesignz2]

Gotta say that the issues you mentioned don't instil me with a lot of confidence. I think the Topping DX5 II is pretty close to being released, so I might wait for that instead since I know Topping gear decently okay, and I haven't had any of those types of problems with any of their gear.

How are you liking the DX5 II now ?