RME ADI-2 DAC Review
January 27, 2018 Luckbad 4
After attracting the attention of the audiophile community with the ADI-2 Pro, RME set its sights on us once again with the new ADI-2 DAC.
It does away with the analog-to-digital conversion that was part of the Pro unit while providing quite a few feature enhancements targeted specifically at music lovers.
Some of the audiophile-focused improvements in the ADI-2 DAC over the Pro include:
- A super low noise IEM output
- An auto-dark option that turns off the screen when you aren’t changing settings
- It now comes with a nice remote
- Includes an improved clock (SteadyClock FS) over the Pro
- Tuned analog circuity (they say it’s slightly better objectively)
- It’s black! I consider this a feature.
- It’s also half the price of the ADI-2 Pro since it is a DAC/amp and not an ADC (and also removes the balanced headphone out option).
The ADI-2 DAC offers balanced/unbalanced analog outputs, an Extreme Power headphone output, a super low noise IEM output, SteadyClock FS, 4-stage hardware output level control, DSP-based signal processing, external power supply operation, Class Compliant USB compatibility and sample rates up to 768 kHz as well as DSD and Direct DSD playback. The SPDIF input signal can even be recorded via USB – as one would expect from RME the DAC is a true 2 channel Full Duplex audio interface.
To address the home and HiFi users, RME exchanged some of the Pro’s studio features with typical home and HiFi ones. With an adapted feature set and much simplified operation RME proudly presents the ADI-2 DAC. Built on the technology, concept and features of the ADI-2 Pro, the DAC concentrates on DA conversion in top high-end quality, along with two exceptional outputs for headphones and IEMs, and – a remote control.
Its ground noise floor is an astounding 10 dB lower than the one of the Extreme Power output (black hole background…), output impedance is near zero Ohms, THD reaches new record lows, click-free on/off is included as well as volume ramp-up, and the sound quality with any IEM is just amazing.
RME ADI-2 DAC Features and Specifications
I would also highly recommend that you take a look at the incredibly detailed manual. Seriously, it’s a sight to behold.
- 2 Channel Digital / Analog Converter
- SPDIF (AES/ADAT) Interface
- 32 Bit / 768 kHz Digital Audio
- USB 2.0 Class Compliant
- Extreme Power Headphone Output
- Super Low Noise IEM Output
- Digital Signal Processing
- Advanced Feature Set
- Remote Control
Stream of Consciousness Impressions
Rather than a compiled retrospective review, I prefer to present stream of consciousness impressions. This will reveal the journey I took while listening rather than being published as a proper summary review.
- DA Filter options including FR curves and impulse responses to show you what they do (in the manual). I might prefer “Slow,” even over NOS.
- Crossfeed works on line out, not just headphone outputs
- You can diagnose your USB! Super useful for peace of mind. USB diagnosis field right in the MADIface driver control panel. Bit Test will tell you if anything went wrong when you play back their super quick test files.
- The best manual I’ve ever seen for any hi-fi product. I love reading it. They also give you a nice glossy-paper ringed manual with it. Something fun to thumb through while listening.
- Exceptionally clean, even from USB.
- Built-in 5 band parametric equalizer that shows you exactly what it’s doing. Has 20 slots to save and the ability to instantly recall previous settings (back and forth) to listen for changes.
- Nice remote with programmable buttons.
- Independent settings for line out, HP out, and IEM out for volume, crossfeed, etc. It automatically mutes the line out (you can change that) and recalls the volume of the appropriate output.
- The headphone and IEM outputs quickly ramp volume up, but it takes long enough that you can change the volume or take off your headphones if you’re about to deafen yourself.
- 9 Setups that you can save (and factory default) and recall. You can set and save every setting via setups apart from EQ (which are saved separately), then program these to the 4 programmable remote buttons to very easily swap between settings. Do I prefer the Slow filter with a bit of Crossfeed or SD Sharp with no Crossfeed? One button, boom.
- Display settings can be changed to have a dark background instead of the default light. You can swap the default state screen between State Overview (cool stats), a really nice FR spectrum display, or a simple display that shows volume and basic output info. You can also turn on auto-dark to turn off the display 10 seconds after you adjust something on the unit (3 seconds if you change something via the remote).
- I’m liking this more than any DS DAC I can remember. Could be because it’s paired with better gear otherwise.
- As a transportable unit, this thing is unbelievably good. You can run it off a battery pack (not included) if you need to use it in a portable situation. Doesn’t need a nice power supply because it cleans everything up internally.
- This is probably the best single unit setup I can imagine for using at the office. It’s compact, cleans up USB, cleans up power, works with full-size cans and IEMs, and doesn’t look garish at all.
- For PRT fans, you can invert phase of both or either channel on the unit instead of doing it in software. The DSP is before the DAC, so the DAC and anything its connected to should benefit from the Phase Reversal Trick.
- A feature I won’t use but that would be great for some is that you can record S/PDIF (coax, optical, or AES with an adapter) into the USB. I think this means you could use a CD player to record stuff? I dunno. Might be useful for some guitar FX units.
- Neat feature: The faster you turn a knob, the bigger steps the value takes. One notch, when turned slowly, is 0.5dB of volume. Turn it fast, and one notch is several dB.
- The headphone output on this is quite a bit better than I was anticipating. Better than most solid state amps I’ve used. It’s a shame that the size of the unit doesn’t allow for an XLR output since the DAC is balanced. Maybe in a v2 in a few years, they can relocate the power button and squeeze a balanced headphone out in (this would raise the price unfortunately).
- The intelligent Loudness function is pretty slick. Basically, you set the bass and treble gain levels of the loudness feature, then set the minimum volume at which it reaches those boosts. As you approach the threshold, it interpolates how much boost is needed to retain some punch and sparkle even at lower volumes.
Bug: If you rapidly swap between coax and USB inputs (for me, that means swapping inputs every couple of seconds to compare their sound), after several swaps the USB goes into robotic music through spring-loaded tin cans mode. I think that means it loses sync with the clock (it uses the internal clock for USB and slaves to external input via coax). If I go back to coax for a couple of seconds then back to USB, it corrects itself (as does stopping/starting the music).[Update] This is fixed in current firmware.
- Quirk: It seems to present itself as a different device to Windows for every sample rate. I noticed because switching to a 96kHz album from 44.1 suddenly started piping the Overwatch League game I was watching through the ADI-2 DAC because Windows always makes new devices the default (simultaneously with JRiver ASIO, so kinda cool that it can do that). Checking my playback devices showed that it didn’t have the custom icon (RME logo) or name I gave the device, then I noticed that 96kHz was the only sample rate shown. Sure enough, it does this once for each supported sample rate (then Windows remembers your settings for that SR from then on). Doesn’t seem to do it for DSD. [Update] In current firmware, the Class Compliant mode is fully compatible with Windows 10. You do not have to install a driver to get all sample rates, and players using WASAPI can change sample rates automatically.
- Speaking of DSD… you can do Direct DSD via line outs only since you’re not allowed to manipulate the volume (DSD also works with the headphone outs, but not Direct DSD). It silences the headphone outs if you turn on DSD Direct. I believe it converts DSD to PCM internally if you leave that setting off, which is default.
- The menus recall where you last were when you go back to them. The screen is nice and crisp on the unit and menu navigation and manipulation is really simple after you acclimate to it.
- In addition to the parametric EQ, you have bass/treble knobs. You can define the cutoff frequency and Q factor of the bass/treble knobs separately from the parametric equalizer.
- I love the integration of some old school hi-fi features like Loudness, Bass/Treble, EQ, and balance controls brought up to modern spec. It’s like an homage to old receivers, but re-imagined as advanced alien technology.
- The USB on the ADI-2 DAC really is stellar. It’s at least in the same playing field as Schiit Gen 5, if not better. I’m pretty sure I still prefer the Lynx AES16e feeding it AES via coax, but it’s good enough to not get too much nervosa over using it.
- I’m a little bit in love with this right now. It’s not just the honeymoon period, it’s the wedding night.
- The tech on the ADI-2 DAC is astonishingly good. It’s so freakin’ versatile.
- USB Nervosa, Solved? The USB Diagnosis feature has to be the most reassuring component of any USB driver I’ve ever used combined with the Bit Test on the unit that tells me that indeed the bits I’m sending are bitperfect:
- The headphone out on the RME ADI-2 DAC is surprisingly good. Unlike some DACs that happen to have a headphone output that I’ve used, this doesn’t not sound at all like an afterthought. I have it in Hi-Power mode and it works very well with the Audeze LCD2Cs and more than adequately with the Sennheiser HD650s.
- I’m using the Jan Meier crossfeed setting as well as inverting the phase on the right channel for the Phase Reversal Trick with the Sennheisers.
- I still haven’t fully settled on a DAC filter. SD Slow, Slow, and NOS are are getting some head time.
- The noise floor is dead silence. I can max out the volume on the ADI-2 DAC and the Project Sunrise III or Liquid Crimson and hear nothing without music playing on Audeze LCD2 Classics.
- While I’ve seen no confirmation that this uses the AK4490 (note: I did later confirm this with Synthax), I can’t imagine they managed to get the AK4497 in there yet, and the specs largely match the ADI-2 Pro (which uses the AK4490). It also has the right number of filters (4497 has 6), does DSD256 instead of DSD512, etc.
- I’ve decided that I generally like the Loudness function. It’ll eventually be one of the main reasons I store Setups (the Loudness floor needs to be different for different headphones and music software). I have it set fairly low both in amplitude and minimum volume required to kick in, but it’s nice as I frequently listen at very low volumes.
I wish the remote could be programmed with a couple more options. DAC Filter cycling would be nice for testing. I’d also like to be able to assign a button to scroll through the main Meter Screens (the default screen). The only way to do that is press encoder button 1 or 2 on the physical unit.[Update] This is now included in current firmware.
- Is it as organic and “right” sounding as a really good R-2R DAC? No, not really. But, it’s so versatile and appeals way too much to my desire to tweak things that I’m currently willing to make that sacrifice. I was looking for black Gumby before, but I’m not now. Maybe something will strike my fancy again one day and this will end up as my work unit.
- I mentioned this once already, but this the ideal work combo unit for me. Your USB and power can suck and it’ll still work great. It’s small and unassuming enough to sit quietly off to the side without drawing attention. And, it works with IEMs.. I still haven’t tried any with it (okay fine, I just tried some right now and there’s no hiss. My G10s are at work). Now I’ll need to get myself a second one later in the year just for work…
- An image from AKM/Teac AK4490 marketing material sure to taint your confirmation bias: DAC filter tone and soundstage depth chart
- The ADI-2 DAC has changed my mind about delta sigma chips being inherently crap. I really love this little thing.
- Even without exotic magic like crossfeed, loudness, or parametric equalization, I actually think it sounds very good. By sounds, I mean it seems about as neutral as a DAC can get if you apply no changes to the signal with it.
- The USB is good enough that paying for a Lynx or Focusrite product to output S/PDIF or AES is unnecessary.
- The headphone amp is neutral and powerful. It works well with the Sennheiser HD650, Audeze LCD2 Classic, and Future Sonics Spectrum G10. Am I also coming around to the use of op-amps?
- The HD650s are better from the Liquid Crimson for sure, but they sound great from the ADI-2 DAC. Audeze LCD2 Classics sound nearly as good from the RME as the Cavalli (blasphemy). It looks like in Hi-Power mode it can pump 1.5 Watts into 32 Ohms (vs. 100mW in Lo-Power).
- Someone on Head-Fi noted click/pop sounds when you change digital filters. I never mentioned it because I assumed it was normal. It is. It’s inherent to the DAC chip and there’s nothing RME can do about it. Don’t worry about it. You’ll get a momentary click sometimes when switching to a different filter.
- Speaking of filters, I find myself migrating to the Short Delay Slow filter most of the time. No particular reasons I can enunciate other than “it sounds good to me.”
- I’ve started transporting the ADI-2 DAC in a carrying case to work daily because I miss it when I don’t have it around.
- It’s been great with my Future Sonics Spectrum G10 IEMs.
- I mentioned that I often use Crossfeed and Loudness. I only use Loudness when I listen at low volume (I just turn it all the way off otherwise). Crossfeed I do tend to use with the LCD2Cs but generally not with the HD650s.
- I’ve been trying to decide if I hear any clear differences between its USB alone and having a Schiit Wyrd in front of it. Maybe the Wyrd combo sounds a little more clinical? Probably in my head. I’m just leaving the Wyrd out of the chain because it is not needed.
- I picked up a Chanzon 12V 5A power adapter for work so I can disconnect the power at home and transport the unit alone. It’s been working great for me so far and is actually UL listed unlike a lot of the PSUs I saw on Amazon.
- The optical input is even surprisingly good coming straight out of my motherboard. Magical jitter correction or some such must be involved.
- I do love that this can handle any file I throw at it. I only have a few files that can test the boundaries of the ADI-2 DAC, but it is able to play them all flawlessly.
I absolutely love the RME ADI-2 DAC. The incredible feature set, build quality, sound, and ease of use are all in a class of their own, especially in the price range.
I have come to enjoy listening to and using it so much, I’ve taken to transporting it back and forth between work and home on a daily basis.
It’s a stellar digital-to-analog converter with an outstanding headphone output and unmatched features. I cannot recommend it highly enough.
The RME ADI-2 DAC is impressively transparent. When I imagine what a neutral DAC sounds like, this is what I envision. But, you can tweak the sound from perfectly analytical toward whatever might be your personal preference with different DAC filters, crossfeed, and equalization.
Combined with the Cavalli Liquid Crimson, the ADI-2 DAC is what I consider a proper reference system. Unbelievably low noise floor and transparency are in harmony with musical enjoyment.
Yes, this is coming from someone who is notorious for only enjoying R-2R DACs. I love multibit, vintage, NOS, tubes, and all the rest. But, I have to tell you, the RME ADI-2 DAC has almost made me forget I even own these things. It’s such a joy to use and listen to.
I don’t even use it with my Lynx AES16e that I once considered an indispensable source component because the ADI-2 DAC’s USB input is so well-executed. My MHDT Labs Orchid (TDA1541A NOS Tube DAC) and Monarchy Audio Model 22 (vintage PCM63P-K DAC) are both sitting in the closet now with the RME taking over primary DAC duties.
RME Audio targeted the audiophile market with the ADI-2 DAC and struck gold.
RME ADI-2 DAC Technical Specifications
- Lock Range: 28 kHz – 200 kHz
- Jitter suppression: > 50 dB (2.4 kHz)
- Jitter when synced to input signal: < 1 ns
- Accepts Consumer and Professional format
- 1 x RCA, according to IEC 60958
- High-sensitivity input stage (< 0.3 Vpp)
- AES/EBU compatible (AES3-1992)
- 1 x optical, according to IEC 60958
- ADAT compatible
- Output level switchable +19 dBu, +13 dBu, +7 dBu, +1 dBu @ 0 dBFS
- Signal to Noise ratio (SNR) @ +7/+13/+19 dBu: 117 dB RMS unweighted, 120 dBA
- Signal to Noise ratio (SNR) @ +1 dBu: 115,4 dB RMS unweighted, 118,9 dBA
- Frequency response @ 44.1 kHz, -0.1 dB: 0 Hz – 20.2 kHz
- Frequency response @ 96 kHz, -0.5 dB: 0 Hz – 44.9 kHz
- Frequency response @ 192 kHz, -1 dB: 0 Hz – 88 kHz
- Frequency response @ 384 kHz, -1 dB: 0 Hz – 115 kHz
- Frequency response @ 768 kHz, -3 dB: 0 Hz – 109 kHz
- THD @ -1 dBFS: -112 dB, 0.00025 %
- THD+N @ -1 dBFS: -110 dB, 0.00032 %
- THD @ -3 dBFS: -116 dB, 0.00016 %
- Channel separation: > 120 dB
- Output impedance: 200 Ohm balanced, 100 Ohm unbalanced
As output XLR, but:
- Output: 6.3 mm TS jack, unbalanced
- Output level 6 dB lower than XLR (-5 dBu to +13 dBu @ 0 dBFS)
- Signal to Noise ratio (SNR) @ +13 dBu: 117 dB RMS unweighted, 120 dBA
- Signal to Noise ratio (SNR) @ +1/+7 dBu: 114/116 dB RMS unweighted, 117/119 dBA
- Signal to Noise ratio (SNR) @ -5 dBu: 109 dB RMS unweighted, 113 dBA
As Cinch, but:
- Output: 6.3 mm TRS jack, unbalanced, stereo
- Output impedance: 0.1 Ohm
- Signal to Noise ratio (SNR) @ +22 dBu: 117 dB RMS unweighted, 120 dBA
- Signal to Noise ratio (SNR) @ +7 dBu: 116 dB RMS unweighted, 119 dBA
- Output level at 0 dBFS, High Power, load 100 Ohm or up: +22 dBu (10 V)
- Output level at 0 dBFS, Low Power, load 8 Ohm or up: +7 dBu (1.73 V)
- THD @ +18 dBu, 32 Ohm load, 1.2 Watt: -110 dB, 0.0003 %
- THD+N @ + 18 dBu, 32 Ohm load: -107 dB, 0.00045 %
- THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB, 0.0003 %
- Max power @ 0.001% THD: 1.5 W per channel
- As Phones, but:
- Output level at 0 dBFS: -3 dBu, 0.55 V
- Signal to Noise ratio (SNR) @ -3 dBu: 115 dB RMS unweighted, 118 dBA
- Max power, 8 Ohm, 0.001% THD: 40 mW per channel
- Clocks: Internal, SPDIF In
- Low Jitter Design: < 1 ns in PLL mode, all inputs
- Internal clock: < 800 ps Jitter, Random Spread Spectrum
- Jitter suppression of external clocks: > 50 dB (2.4 kHz)
- Effective clock jitter influence on DA conversion: near zero
- PLL ensures zero dropout, even at more than 100 ns jitter
- Additional Digital Bitclock PLL for trouble-free varispeed ADAT operation
- Supported sample rates for external clocks: 28 kHz up to 200 kHz
- Internally supported sample rates: 44.1 kHz up to 768 kHz
- Included power supply: external switching PSU, 100 – 240 V AC, 2 A, 24 Watts
- Standby power consumption: 120 mW (10 mA)
- Idle power consumption: 7 Watts, Max. power consumption: 18 Watts
- Idle current at 12 V: 570 mA (6.8 Watts)
- Dimensions (WxHxD): 215 x 52 x 150 mm (8.5″ x 2.05″ x 5.9″)
- Weight: 1.0 kg ( 2.2 lbs)
- Temperature range: +5° up to +50° Celsius (41° F up to 122°F)
- Relative humidity: < 75%, non condensing
Internal pictures of the RME ADI-2 DAC from the excellent ProSound.iXBT.com Review
I’ve edited some of the bugs/quirks in-line with updates that have been fixed since I initially wrote this review. RME is doing an outstanding job of supporting the ADI-2 DAC. Here are (some of) the mirrored notes from the latest firmware so you can take a gander at the updates that were done to the firmware in 2018 alone (now on FPGA 26, DSP 25).
12/21/2018 ADI-2 Pro updated to 185/90, ADI-2 DAC updated to 26/25. The new feature ‘Do not Show Vol Screen’ no longer makes the Bass & Treble screen disappear. Feature change: the Q value in the PEQ can now be dialed up to 9.9 in bands 1 to 3. DAC only: The Bit Test was shifted to the next bit level.
11/26/2018 ADI-2 Pro updated to 185/89, ADI-2 DAC updated to 26/24. Switching between SPDIF Single Speed and USB Double Speed or higher USB audio could become distorted. The USB Sample Rate (SR) shown in the Status Overview screen is now the real USB sample rate. Avoid click sounds when changing Hi-Cut corner frequency over a bigger range. Dual EQ correctly shows left or right channel settings and L or R in the title bar within the graphical EQ screen. The current Loudness values of Bass/Treble boost are now taken into account for the AutoRef Level switching thresholds. I/O menu – Volume shows the correct values at lower settings. The vertical AutoScroll (push and hold encoder 1 or 2) reacts and works quicker. Improved the Volume knob behaviour to prevent bigger steps of volume changes when turning the knob with slow and medium speed. Total Reset: The combination of pressing encoder 1 and 2 plus the VOL key will now also erase the EQ curves. New option in SETUP – Options – Display: Show Volume Screen. New option in I/O menu: Lock Volume, disables the Volume knob. ADI-2 Pro only: The digital trim gain for the analog inputs is now set separately for left and right channel. Dual volume linked mode (both Phones outputs in use, selection marker on both) is no longer lost after power off/on. Added ‘PEQ+B/T+LD 1-4’ as action to the Remap Function Key list. ADI-2 DAC only: Switching from USB playback at more than Single Speed to SPDIF at Single Speed could cause a left channel click.
09/27/2018 ADI-2 Pro updated to FPGA 183, ADI-2 DAC updated to FPGA 23. Improved data flow control in asynchronous Class Compliant mode which now works perfectly even with critical hosts. ADI-2 DAC DSP 23: added the missing mute of the IEM output in DSD Direct mode.
08/20/2018 ADI-2 DAC updated to DSP22. Better overview in the SETUP – Options menu, new menu page Display. Lowest Low Vol Ref value in Loudness is now -90 dB.
07/16/2018 ADI-2 DAC updated to FPGA 20.
06/26/2018 ADI-2 DAC updated to FPGA 17 / DSP 21, ADI-2 Pro to FPGA 177 / DSP 87. Class Compliant compatibility for Windows 10 and Squeezebox Touch adjusted. Note: The mode Multichannel (ADI-2 Pro) does not work well under Windows 10 (no Wasapi, incorrect input handling, faulty loudspeaker setup). Additionally on every change from Stereo to Multichannel and back the device needs to be uninstalled in the Device Manager, then re-added via Actions – Scan for hardware changes, for it to work in the selected mode. Dual EQ: Save state to preset slot Temp after activation in the I/O menu. Only ADI-2 Pro: Level Meter of analog inputs simultaneously tracks pre and post EQ. This way overloads stay visible and Auto Ref Level works correctly even when the EQ is used to attenuate the signal. Added compensation filter for the AD-converter to reduce ripple in the frequency response for PCM, 44.1 up to 192 kHz, filter modes SD Sharp, Sharp, SD Slow, Slow (for details check the thread in the RME forum about this firmware update).
03/19/2018 ADI-2 DAC updated to FPGA 11, DSP 20. Newly programmed DAC subclock module. Reworked several reset and initialization schemes in various modes and sample rates. Playing a PCM file at 176.4 kHz followed by a DSD64 file could cause a 250 ms noise burst during transition. The automatic DSD DoP detection can now be disabled (Default: SETUP – Options – Device Mode – DSD Detection – ON). New Remap Keys option ‘Toggle Screen’ to change between Analyzer, Dark Volume and State Overview with the remote.
01/29/2018 ADI-2 DAC updated to version 10/19. SteadyClock FS improved. Option Polarity is now also available in mode DSD and DSD Direct. Changed: Switching the unit off, display and LEDs will go out simultaneously. Fix: In AutoDark mode a key press on a Remapped key at the unit did not activate the illumination. Impedance-based level meters did not work correctly.