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FX Audio DAC-M1 Review (DAC & Headphone Amp)

amirm

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This is a review and detailed measurements of the FX Audio DAC-M1 DAC, headphone amplifier and Bluetooth receiver. It was sent to me by the company and costs US $219.

The DAC-M1 is a cute little thing!

FX-AUDIO DAC-M1 Review USB DAC and Headphone Amplifier.jpg


It also comes in vibrant blue and pink! A very responsive OLED display shows all the information about the unit which I like although would be nice to have the volume in the middle in much larger font and PCM in top right. You can select both RCA and Headphone outputs to be active at once. Or have it switch based on whether you plug a headphone in or not. Pushing the volume control gets you into the menu to select inputs, filters, output states, etc.

Volume control is linear which I usually don't like as it can take forever to change volume. Here, the interface is so responsive that it mostly works and yet gives high precision to adjust levels.

Power is provided by an external 12 volt switching power supply which has dual cords, making it less of a chore to plug in:

FX-AUDIO DAC-M1 Review Power Supply USB DAC and Headphone Amplifier.jpg


Its power cord is also more flexible than typical which I appreciated.

A remote control is provided which I did use or test.

FX Audio DAC-M1 DAC Measurements
Let's start with testing the DAC by measuring the RCA output in the back. I found that I had above average trouble keeping ground loops out of the measurements. One channel seemed to be more sensitive than the other. Eventually a single grounding link between Audio Precision analyzer and its ground did the trick:
FX-AUDIO DAC-M1 Measurements USB DAC and Headphone Amplifier.png


Distortion is at -120 dB and lower which is utterly inaudible. Add some noise to it and our SINAD lands at 110 dB which is in excellent category of some 350+ DACs tested so far: (you can click on this chart to see if full size)

Best DAC and Headphone Amplifier Review.png


Zooming in, this is its neighbors:

Best DAC and Headphone Amplifier Review Zoomed.png


Jitter test showed a bit of low frequency components around our main 12 kHz signal:

FX-AUDIO DAC-M1 Jitter Measurements USB DAC and Headphone Amplifier.png


Switching to Toslink (red) eliminated that but created spikes which represent data that is in the J-Test signal but should be at much lower levels. Either measurement shows a bit less than superb jitter management but absolutely no audible concern at -120 dB and lower.

Dynamic range is not state of the art but essentially at threshold of hearing:

FX-AUDIO DAC-M1 DNR Measurements USB DAC and Headphone Amplifier.png


Dual tone test (low and high) intermodulation test shows the classic ESS DAC "IMD hump" which we discovered a few years ago:

FX-AUDIO DAC-M1 IMD Measurements USB DAC and Headphone Amplifier.png


Linearity is excellent:

FX-AUDIO DAC-M1 Linearity Measurements USB DAC and Headphone Amplifier.png


Multitone results are extreme good:

FX-AUDIO DAC-M1 Multitone Measurements USB DAC and Headphone Amplifier.png


Nice subset of filters are provided with my favorite, F3, as the default:

FX-AUDIO DAC-M1 Filter Measurements USB DAC and Headphone Amplifier.png


Very few DACs offer such nice cut off at 22.05 kHz even though that is what the theory says is optimal. We have it hear which pleases me to no end. :)

Attenuation of the filter is low though so causes the levels of THD+N versus frequency to elevate at higher frequencies:

FX-AUDIO DAC-M1 THD+N vs Frequency Measurements USB DAC and Headphone Amplifier.png


In case you are interested in its performance at lower levels and at max, here it is:

FX-AUDIO DAC-M1 SINAD vs Output Measurements USB DAC and Headphone Amplifier.png


FX Audio DAC-M1 Headphone Amplifier Measurements
Let's start with our dynamic range when reducing the output to just 50 mv:

FX-AUDIO DAC-M1 SNR Headphone Measurements USB DAC and Headphone Amplifier.png


Most quiet heapdhone amp reviewed.png


This is a weak performance. I looked at the spectrum (not shown) and it is dominated by power supply noise at 120 Hz. So fortunately not as audible as if it had been at higher frequencies where our hearing is most sensitive.

Most important tests here are power so let's start with 300 ohm load:

FX-AUDIO DAC-M1 Power into 300 ohm Measurements USB DAC and Headphone Amplifier.png


That power supply noise definitely knocks the performance down at lower output levels but then the ship right itself above 1 milliwatt and goes past my requirement of 100 milliwatts with this load. No clipping is observed which means you can crank it up as much as you like.

Similar story holds for 32 ohm load:
FX-AUDIO DAC-M1 Power into 32 ohm Measurements USB DAC and Headphone Amplifier.png


By the way, as a test I powered the unit using my lab power supply and it made no difference. So the noise is internally generated.

FX Audio DAC-M1 Listening Tests
I started listening with my Dan Clark Stealth headphone. There is enough volume here for average listening. Even at max volume there is no sign of distortion. Switching to Drop Ether CX, produced more volume making it suitable for these headphones. Switching to Sennheiser HD-650 really brought out the power allowing me to listen at levels that could cause hearing damage and again, with no sign of distortion.

Conclusions
It is easy to see that the company has aimed high with this combination DAC and headphone high. You wouldn't expect state of the art performance at this level and you don't get that. But transparency is provided almost across the board with plenty of power to drive a range of headphones. It is nice to have different options in this class of product so you can choose based on price, features, looks, support, etc.

I am going to recommend the FX-Audio DAC-M1.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

solderdude

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What happens around 0.3V output voltage (regardless of the load) ?
 

kyllwtr

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Curious to see how much improve the 120Hz data with a better DC power supply...
 
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amirm

amirm

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Curious to see how much improve the 120Hz data with a better DC power supply...
I tried that and mentioned it in the review. :) It made no difference with my lab power supply.
 
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amirm

amirm

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I find it funny you've probably personally listened to more devices than the subjectivists who constantly say measurements don't matter and, "have you heard it though?".
Indeed. I listen to more audio devices in a week than most of them do in a month or a year!
 

mohragk

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Is it possible to add the price of each DAC in the overall raking? It would be a lot of work initially, I know, but it would be very helpful for people just seeking out the best DAC for a set price.
 

GWolfman

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Interesting little thing. I wonder now if any of their other devices are competent/decent as well. Off to search...
 

FreaK

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Wait a minute.. your DCA Stealth? So you bought it, its that good, or is it the test sample, and you have to send it back? :)
 

Helicopter

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Thanks Amir. This is better than I expected. Nice little amp.

My main takeaway from this review is that I need to get DCA headphones. I just need to pick the Noire or the Stealth.

Wait a minute.. your DCA Stealth? So you bought it, its that good, or is it the test sample, and you have to send it back? :)
He made a deal to keep it, detailed a bit in the Stealth thread.
 

solderdude

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An output stage like the one below could possibly have this type of issue ?
buf schem.png
 

rodrigaj

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This may seem picky, but I much prefer a physical "Preamp" switch on the unit that allows desktop monitors to be plugged in along with HP's. With the desktop unit at arms length, you switch between HP's and monitors. The JDS El Amp is an example.

I don't like "intelligent" sensing that forces you to pull out the HP plug and I don't like a signal being routed to my HP's when they are not in use.
 
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