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Review and Measurements of Monoprice Liquid Spark Headphone Amp

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#61
Hello! I'm new here. Nice to see such a detailed measurements of budget friendly DAC/AMPs, thanks for that!
I'm deciding between the below units, appreciate if you could help me to choose the correct one. I'm planning to use them with Beyerdynamic DT770 250 ohms, source will be either laptop or smartphone headphone output. Budget 100-150$. Portability is not a major focus, just performance and quality.
1. JDS Labs Atom - liked the measurements so much but then some videos on YouTube decreased a faith in it. Especially volume pot and volume difference between the channels. Seems it is like a lottery, don't know what you get. I'll have to import in Europe so I won't have any options to return or exchange.
2. Liquid Spark - does this really perform much worse than JDS Atom? I like its design compared to Atom.
3. Fiio A5 or K5 - would like to hear some major differences between these two in capability of power delivering in 250-300 ohms impedance range.
Thanks in advance!
 

Jimmy

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#62
There are many good/decent amps out there, just not a low priced single one that ticks all boxes, the very low output impedance of the Atom may not pair all that well with certain bass shy headphones, for example. JDS Labs distribution in Europe is not that good, and I wouldn't mind paying a bit more if they include a metal chassis and a better quality volume pot.

The Spark is also a good amp, not as technically proficient as the Atom, but the root problem is similar, shipping cost and taxes put it into another price category when buying outside USA.

With your headphones probably any decently designed TPA6120 based amp will sound good, for example you can buy for 79 pounds in Amazon UK the Monoprice Desktop Amp/DAC, it has 10 ohms output impedance and the DAC is just utilitarian, but as amp I'm using it with a Topping D30 and headphones with impedances ranging between 30 and 300 ohms and I have no complains, measurements are nothing to write home about compared to the Atom or newer amps, but it does the job (just take into account that it is a bit warmer than neutral).

Here there are some measurements: https://www.changstar.com/www.changstar.com/index.php/topic,2620.0.html

The SMSL SAPII is also TPA6120 based and cheaper, but with the Monoprice you get a DAC for just a little more.
 
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#63
There are many good/decent amps out there, just not a low priced single one that ticks all boxes, the very low output impedance of the Atom may not pair all that well with certain bass shy headphones, for example. JDS Labs distribution in Europe is not that good, and I wouldn't mind paying a bit more if they include a metal chassis and a better quality volume pot.

The Spark is also a good amp, not as technically proficient as the Atom, but the root problem is similar, shipping cost and taxes put it into another price category when buying outside USA.

With your headphones probably any decently designed TPA6120 based amp will sound good, for example you can buy for 79 pounds in Amazon UK the Monoprice Desktop Amp/DAC, it has 10 ohms output impedance and the DAC is just utilitarian, but as amp I'm using it with a Topping D30 and headphones with impedances ranging between 30 and 300 ohms and I have no complains, measurements are nothing to write home about compared to the Atom or newer amps, but it does the job (just take into account that it is a bit warmer than neutral).

Here there are some measurements: https://www.changstar.com/www.changstar.com/index.php/topic,2620.0.html

The SMSL SAPII is also TPA6120 based and cheaper, but with the Monoprice you get a DAC for just a little more.
Thanks for your attention and for discovering more options for me.
I've done some googling and it seems SMSL SAPII has 10 ohms output impedance as well as Monoprice Desktop Amp/DAC does.
I'm also considering to purchase Audio-Technica ATH-M50x headphones, and probably I'd like to get an amp with low output impedance to future proof it (I've read many threads stating to always consider 8 x ohms rule to avoid modification of frequency response).
If we don't take into account additional shipping costs, will Monoprice Liquid Spark be a good alternative compared with SMSL SAPII and Monoprice Desktop Amp/DAC?
 

Jimmy

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#64
The problem is more related to impedance variations with frequency, the Ath-M50 has an almost planar like ruler flat impedance curve, so I don't think 10 ohms will make a difference.

However, if the DAC absence and price difference is not important I would go for the Atom or the Spark, although I doubt there will be any meaningful audible differences with the other higher impedance amps mentioned, unless something like IEMS are used.

If you go with the Monoprice desktop, note that there's a big difference between high and low gain, low gain sounds better/ more transparent with every headphone that I tested.
 
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#65
Thanks again.
Regarding Monoprice Desktop Headphone Amp, it states 150 mW in 300 ohms load. I wasn't able to find at what distortion value it was measured. Is it very low or just around 0.1%?
 

Jimmy

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#66
I don't know, the only measurements that I found are at the link that I posted before.

As a reference, in low gain with a Topping D30 as source and 300 ohm HD600 I listen at about 10 o'clock, past 12 o'clock sound level is uncomfortably high.

The internal DAC level output level is noticeably lower, and it works better as an amp than DAC.
 

Jimmy

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#68
What I mean is that power is more than enough, it can power HD600 in low gain without problems, I don't know about Beyer DT770 though.

Do you have a DAC?, if you don't you may want to go to something like a Topping DX3, as I said the Monoprice is better as an amp, the internal DAC is decent but not great.
 
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#69
No I don't have a dedicated external DAC, I'm using Sony Xperia XZ Premium with its Qualcomm WCD 9335 DAC and HP laptop with IDT High Definition Audio Codec. Datasheets for both of them look pretty good. That's why I'm trying to find a good amp to pair with.
But is seems now I'm completely lost... :)
 

Jimmy

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#70
In that case I would go for an all in one solution, for example with the DX3 Pro you have a good DAC and headphone amp, and you can play music wirelessly from your phone using bluetooth. You will spend a bit more now but will save money in the long run, I see offers for it in Amazon but they are not prime (ship from China), Audiophonics has it, too.

The Monoprice Amp/DAC uses a PCM1793 and it's not bad, I used it on a secondary rig during months and it was OK, but when plugging a good external DAC the sound improved significantly, so the internal DAC is the weak link.
 
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#71
I suppose the reason why external DACs perform well is because of 2V input signal they're able to deliver, which is not always possible to achieve from a laptop or smartphone 3.5 mm jacks, even at max volume.
DX 3 PRO really looks good but its price (230$) really bites a little bit. Even for 30$ less its possible to get separates as well, like Topping D30/A30 combo or D30/Liquid Spark for example.
If we also neglect portability, which way would you go in terms of quality and reliability?
Thanks again for your time and effort
 

Jimmy

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#72
For an all in one unit price for the DX3 pro is reasonable give its performance, any of the alternatives you mentioned are OK, you can try the Monoprice Amp/DAC for yourself, you may find it enough as a combo, the main problem of the internal DAC is the low output level to the headphone amplification stage (and some people say the RCA outputs, mainly the variable ones distort, I haven't tested them)

For even less money you can buy the FX DAC X6, but measurements are not very good, for portability the Xduoo XD-05 competes with the Chord Mojo, but price is close to the DX3 Pro.

My opinion is that in the long term it's better to invest a bit more initially, and with something like the DX3 pro as a desktop solution there's less (or no) need to upgrade later.
 
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#73
For an all in one unit price for the DX3 pro is reasonable give its performance, any of the alternatives you mentioned are OK, you can try the Monoprice Amp/DAC for yourself, you may find it enough as a combo, the main problem of the internal DAC is the low output level to the headphone amplification stage (and some people say the RCA outputs, mainly the variable ones distort, I haven't tested them)

For even less money you can buy the FX DAC X6, but measurements are not very good, for portability the Xduoo XD-05 competes with the Chord Mojo, but price is close to the DX3 Pro.

My opinion is that in the long term it's better to invest a bit more initially, and with something like the DX3 pro as a desktop solution there's less (or no) need to upgrade later.
Another member joins my shopping list :)
Xduoo XD-05 looks really feature-packed. Unfortunately I wasn't able to find any measurements on it, every website just copies the same technical specification of 500 mW in 32 ohms. No word at what gain setting or distortion level this result was obtained. Also nothing about 300 ohm loads.
I've done some math though, and if for example it was measured in a high gain, then I get 4 volts output from amplifier, this would deliver to 300 ohms load just 53 mW. Too weak for my DT770. But I can be wrong of course, maybe a measurement with 32 ohms was done in low gain mode (logically) and in high gain it could generate more than 4 volts.
I'd really like to see the detailed power vs distortion measurements of this unit.

Edit: I found the measurements, indeed it's really low 50~60 mW in 300 ohms. Looks like similar to Topping NX4 DSD.
 
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#74
My opinion is that in the long term it's better to invest a bit more initially, and with something like the DX3 pro as a desktop solution there's less (or no) need to upgrade later
Agree on that. Thanks and have a nice day ahead!
 
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#75
Gentlemen, I've contacted Monoprice support to verify if PSU of Liquid Spark is 100-240 VAC universal voltage type. I also got a photo (attached) of it from Ebay seller which indeed shows an input voltage of 100-240.
I've sent this photo to Monoprice and this is what I got:
"picture is correct and belongs to liquid spark model, but actual chipset only supports and allow 110v to pass through".
I don't quite understand, chipset of what? PSU??? Then why the hell they did put 100-240 on it?
Any European (or any country with 220V) owner of this amplifier please confirm if it's safe to plug PSU in 220V socket. Thanks
_20190514_200227.JPG
 
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#78
I've done some voltage output measurements of my laptop and smartphone today, and now I can clearly see why an external DAC & AMP are so important.

Output voltage from 3.5 mm headphone jack were measured at max volume on these devices: HP Pavilion DV7 3085dx with IDT Hight Definition Audio and Sony Xperia XZ Premium.
Measuring device: FLUKE 177C True RMS Multimeter :)

I used Audacity on windows, volume set max in windows sound settings and also in audacity. AC voltage reading taken from multimeter. Listed below, are generated tones with various frequencies and voltage reading obtained (with 0.8 amplitude default setting in Audacity tone generation window).

60 Hz - 1.426 V
500 Hz - 1.645 V
1000 Hz - 1.638 V
5000 Hz - 1.337 V
10000 Hz - 0.937 V
15000 Hz - 0.685 V
20000 Hz - 0.528 V

How do you guys explain this voltage variations during different but constant frequency tones? It rises until 500 Hz and then starts falling as the frequency is increased. Above mentioned FLUKE model can measure frequencies much above 20 kHz, so I think these deviations are not caused by the multimeter itself.

Then I decided to measure the voltage during an actual music playback at max volume. For sample track I chose Tina Turner - Steamy Windows, lossless CD quality flac file. I realize that my MM doesn't have enough refresh times to display varied voltages over complete frequency spectrum (nor my eyes do), so I activated MINMAX function mode to capture MIN/MAX/AVG values later.

Laptop:
MAX - 0.823 V
MIN - 0.486 V
AVG - 0.653 V

Smartphone:
MAX - 0.266 V
MIN - 0.126 V
AVG - 0.165 V

So what all these results tell me is that even combined DAC/AMP max volume output of these devices cannot reach 2V which usually comes from an average external DAC only, not to mention amplifier. Measured devices BTW are both high end during their times (1400$ HP laptop and High-Res certified XZ Premium for another 700-800$).

Conclusion: purchasing external DAC is a must!

Please correct me if I have made many mistakes here :) The process was a really great fun though! I could only imagine how more interesting would be to perform various measurements with PRO grade audio measuring instruments.
 
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