Expert review and test of the Mytek Brookly DAC+ by Australian Hi-Fi Magazine. Free pdf download included.

James A. Michener in his 1971 novel ‘The Drifters’ indulges in a bit of cheap psychologising, suggesting hi-fi fans are principally interested in a sense of control. That flies in the face of the minimalism of the past few decades: the shedding of tone controls and graphic equalisers, and the preference for having only a volume knob for control.

That said, when it comes to digital audio there are things that are worth controlling. Michener’s mythical control freak would love the Mytek Brooklyn DAC+ because it has adjustments for just about everything. Hi-fi purists will love it too, for its other virtues… and, perhaps, because it has adjustments for just about everything.

The Equipment
First, what is the Mytek Brooklyn DAC+? It is a DAC. It is a headphone amplifier. It is also a phono preamplifier.

Let’s drill down on those. As a DAC it supports all input types. That is, there are two S/PDIF coaxial digital audio inputs, plus one optical one. There’s a USB Type B socket for use with a computer. And there is an XLR input for the professional AES/EBU digital audio standard.

The different inputs support different maximum signals. The all-round most capable is the USB connection. This supports 16-bit, 24-bit and 32-bit PCM at sampling frequencies of 44.1kHz, 48kHz, 88.kHz, 96kHz, 176.4kHz, 192kHz, 352.8kHz and 384kHz. Windows confirmed that. It also supports standard and double speed Direct Stream Digital (that is, DSD64 and DSD128). The AES/EBU input and the two S/PDIF coaxial inputs offer the same support, except only up to 24-bits of resolution. That includes DSD. The optical input is limited to 176.4kHz sampled PCM and DSD64.

But there’s a special setting where you can use the two wired S/PDIF inputs to accept DSD64, DSD128 and DSD256 from professional DSD recording equipment. That is not something I tested.

The unit also supports MQA decoding for those who stream from Tidal and perhaps gather such music files from elsewhere.

There’s also a word clock I/O, so you can externally clock the DAC if you want to get that deep into things. Its own built-in clock is the Mytek Femtoclock Generator, rated at 0.82ps jitter. By way of comparison, even with 384kHz sampling, the interval between each sample is 2,600,000 picoseconds.

For headphone output there are two front panel 6.35mm stereo ‘phone sockets. They can be switched to support balanced headphones.

The output is rated at up to six watts and up to half an amp of current. When used in standard mode, one of the headphone outputs is in ‘absolute’ phase, while the other is in reverse phase.

For line output you get both RCA sockets and balanced XLR.

There’s a robust three-pin mains socket on the back for power (voltages from 100 to 240 are supported), but there’s also a socket for connecting an external 12-volt power supply. The manual says that some may want to use this to battery-power the device. It can draw up to 17-watts with that connection.

It’s this kind of thing that makes you realise that this device is really about options. You can use the built-in power supply, or go for your own. It’s up to you. You can connect to your system with balanced or unbalanced interconnects. It’s up to you. You can listen in or out of phase through your headphones. And as for analogue input, the pair of RCA sockets can operate in normal line-level mode, or at phono level with RIAA equalisation. There are gain settings for both moving-magnet and moving-coil cartridges. It’s up to you.

The front panel features the aforementioned two headphone sockets, plus four control buttons, a control knob (which is pressable for selecting things, and doubles as a volume control in some modes) and a 65×25mm OLED display panel.

The Mytek Brooklyn DAC+ measures 218×44×206mm (HWD), weighs 1.6 kilograms and is available in black or silver finishes.

Control
Control is via the four buttons on the front panel, along with the knob. It’s pretty straight forward and you soon learn how to do it.

If you’re using the unit principally as a DAC for a computer, then you’ll install the control panel on the computer and will be able to change the settings in that application. On Windows at least I thought the control panel was poorly designed, because instead of having the many options organised into some kind of block, they were spread across the bottom of the panel in a single horizontal line. They would all show only if I maximised the panel on my very high-resolution computer monitor.

Packaged with the unit was the remote control for… an Apple TV. Or you can use a remote control with standard Philips infrared codes (there’s a setting for that). Clever. You get a classy-looking and effective remote control rather than the cheap plastic thing of the kind to which small-volume equipment makers often resort.

Information

I prattle on frequently in my reviews about the importance of a computer DAC telling you what the signal does. It is really, really easy to accidentally select the wrong output setting in most high-fidelity music playback software. Do that and you could end up with DSD being converted to PCM in your computer’s software, or PCM music being re-sampled to something other than the original sample rate. The Brooklyn DAC+ user manual only covers the basics of installation, so it would best to go to the Mytek site and follow the instructions in the online ‘Software Setup User Guide’, which covers Foobar2000, JRiver, Audirvana and Amarra along with some pro software.

The Brooklyn DAC+ has, I think, the best information display I’ve seen. There are two standard displays: a clean simplified one and a fussier, fuller display. Both show the format and the sample rate. And they show the bit resolution of the signal, which is information that is rarely provided. You will be able to listen, confident that your computer’s operating system isn’t doing something behind the scenes to degrade the digital audio signal.

In Use

The Brooklyn DAC+ was delightfully easy to use. Most people will want to stick with the default settings, but if you really want to exhibit a Michener-alleged level of control, you’ll probably want to switch off the MQA decoder, because that opens up a whole bunch of additional adjustments, including no fewer than seven different filter slopes and systems for decoding PCM. There are also several choices for handing DSD decoding, should you wish to use them.

You can choose between a digital volume control and an analogue one. Or you can bypass this so that it only affects the headphones. With that setting the line and XLR outputs bypass the volume control. That’s the way most people will plug it into their system.

Inserting a headphone plug into a socket switches off the line output and engages the level control if it had previously been bypassed. (The previous mode returns when the headphone plug is pulled.)

The sound delivered to my system by this DAC was—how do you say it?—perfect. Well, perfect to the limits of my listening capabilities and, I suspect, perfect to the listening abilities of any human being. Noise? None. Control? As good as it gets. Tonal balance? Exact. List your favourite audible characteristics of a piece of high-fidelity equipment, and the Mytek Brooklyn DAC+ will meet or exceed them.

Naturally I did the great majority of my listening to digital material. But what about analogue? I use a Rega Exact moving-magnet cartridge in a Rega Planar 3 turntable, so I didn’t check the moving-coil side of things. The first thing you notice with vinyl is something that it probably trivial, but something that pleases me.

Way back when, the switch from vinyl to CD also involved turning the volume control rather less in a clockwise direction. Even today, in most cases you have to advance the volume setting for the phono input much higher than for the digital inputs to achieve the same level. But as we’ll see, the output level for this DAC is much higher than the norm. That extends to the phono input. Seriously, I was playing my system with some ten decibels less gain than usual.

After a bit of Prince’s album ‘1999’, with its disappointing absence of deep bass (that’s the album, not the DAC) I moved to Weather Report’s 1982 self-titled album, which I haven’t listened to on vinyl for many years, although I frequently go to the digital version.

I am happy to report that my Columbia half-speed mastered copy sounded simply glorious through this DAC, wearing its phono pre-amp hat. The bass was full and extended, while the kick drum had full impact and full depth. The cymbals were living things between the speakers, and depth and height and width and a sense of tangibility were absolutely first class.

I was torn. I spend most of my time in front of my computer. Should I use the Mytek Brookly DAC+ there with my KEF LS50 speakers and Krix subwoofer…or with my main system where it could do digital and phono?

Sadly, it’ll have to go back, and I’ll get to use it for neither.

Conclusion
If you want the highest quality of sound from your DAC or headphone amplifier, look to the Mytek Brooklyn DAC+. If you want close to the highest level of control from your DAC, look to the Mytek Brooklyn DAC+. # Stephen Dawson

 

Test Report
I measured maximum output levels from one of the headphone outputs in standard (unbalanced) mode. Into a high input impedance (47kΩ) there was the tiniest amount of clipping at the 0dB output level at 100Hz, so I backed it down to –1dB and it was clean. The (effectively) no load output was 8.74 volts RMS. Into a 295Ω test load, the output was 8.74 volts RMS. At least, it was with 1kHz and 10kHz test signals. With 100Hz there was a touch of clipping, so I backed it off to –2dB to clean it up. That reduced the output to 7.93V.

That works out to a 213mW output into high-impedance headphones, or some 23dB higher than the sensitivity rating. These days most headphones are at least in the high 90dBSPLs for 1mW of input, so you can expect a good 120dBSPL if you want it. (You shouldn’t want it.)

Into a 15.9Ω load there was clipping again. At –5dB this was completely gone. The output was 5.26 volts for an incredible 1.74 watts output. That’s 32dB higher than the sensitivity rating. If the headphones could cope. They probably couldn’t.

I calculated an internal resistance of around 0.8Ω, so even headphones with a widely varying impedance curve shouldn’t produce major frequency response changes.

As for the line output, if you set the RCA line output to ‘Bypass’—that is, the volume control has no effect on the output level—then a full-scale 16-bit PCM signal produces a rather high 5VRMS. I think 2VRMS would have been better, since that’s been more or less the convention since the CD was introduced some 35 years ago. Expect to have to turn down the input to which this DAC is connected. On the other hand, that means that any noise caused by electrical interference to the interconnect line will be 8dB quieter than normal… and that’s always a good thing.

Noise was actually very low, as you can see from the measurement above, where the white trace shows the noise when my computer was running on battery and the green trace when running on mains power, both measurements made using 96kHz/24-bit test signals.
 
Most measurements I conducted with 24-bit signals produced results better than –109dBA for noise levels. The charted noise showed it at –130dBA in the upper bass, lower midrange, and falling away to below –140dBA from 1kHz and up.

I want to focus on this for a moment. You see, I had the Brooklyn DAC+ plugged into regular power. I had the Surface Pro 4 also mains powered. I know for a fact that the latter is a noisy arrangement. When I reviewed the Audioquest DragonFly Red DAC, I wrote: ‘With the computer plugged in, the dBA noise level was a 16-bit-like –91.8dB. With the computer unplugged, it was an amazing –109.5dB.’ The computer in question was the same Surface Pro 4.

The Mytek Brooklyn DAC+ produced an ‘amazing’ –109.4dBA noise level. And it didn’t matter a damn whether the computer was plugged into power or running of its battery. The results were identical. In another review I wondered: ‘I don’t know if it’s possible, but ideally at least a DAC would somehow isolate its analogue output entirely from electrical noise delivered over its digital input. DACs work with computers, and computers are noisy.’

Mytek shows that it is indeed possible. And it has done it. Others should follow its lead. Distortion was low. THD was 0.0013% for all signals. IMD was around 0.0045% for 16-bit signals, and 0.003% or better for 24-bit signals.

With CD standard 44.1kHz, 16-bit signals, fed via a USB connection from my Surface Pro 4, the noise was –97.6dBA.

Now, what about frequency response? This is a bit complicated because of those seven different filter shapes from which you can choose. A few tests I conducted showed that the line and minimum phase filters made no difference to the frequency response, so I ran a series of tests using 96kHz sampling to see what affect the fast, versus slow, versus apodizing, versus hybrid, versus brick wall filters had.

Let me cut to the chase. When you feel like it, have a listen to the options to see if one or the other takes your fancy. Meanwhile, if you’re not confident doing that, just stick with the default FRMP—fast roll-off, minimum phase filter—setting. With 96kHz sampling it produced the most extended response, down by 0.28dB at 20kHz, 1dB at 35kHz, and 2dB at 45kHz. The Slow settings start rolling things off faster around 33kHz. Apodizing kind of tracks FRMP to around 43kHz, although with a weird ripple in the measurement, and then hits a brick wall. Hybrid is down further, even at 20kHz (another –0.2dB) and drops sharply shortly before hitting 40kHz. Brick exactly tracks FRMP until just under 42kHz and then cuts off sharply.

Graph above shows frequency response showing effect of FRMP filter using 192kHz/24-bit test signal. Left channel (white trace) vs right channel (green trace).

Do any of those differences make an audible difference? Not that I can hear. But the purist in me says that FRMP seems to be best. Especially when it comes to 44.1kHz sampling. With FRMP selected, the response was down by –0.14dB at 20kHz, and hit a brick wall just a little above 21kHz. The (‘Slow’) SRMP setting had the shoulder at a relatively low 15.5kHz, with the response down by –5dB at 20kHz. The BRCK setting had the shoulder at 19kHz, and 20kHz also at –5dB.

Graph above shows effect of FRMP filter setting (white trace) vs SRMP filter setting (green trace), vs BRCK filter setting (blue trace) vs apodising filter setting (purple trace) using 96kHz/24-bit test signals.

FRMP seems to be the way to go for the flattest frequency response. Its results with 192kHz sampling were similar to those for 96kHz, but more extended: –2dB at 50kHz, –3.2dB at 60kHz, –5.3dB at 70kHz. I am not equipped to measure the response for higher sampling rates, but I imagine that it would be broadly similar. #  Stephen Dawson