In this review, I’m taking a look at the iFi Micro iDSD Signature portable DAC/amplifier. This $649 unit is an updated version of the 2017 iDSD Black Label and it has more features than you can point a stick at. I recently fell head-over-heels for the iFi Audio Zen DAC, so why would anyone need the Signature? Read on to find out.
About iFi Audio
iFi Audio is actually a subsidiary of AMR Audio, a high-end HiFi brand that makes exquisite (and costly) DACs, Phono Stages, Line Stages, Speakers and more. iFi Audio brings the expertise and knowledge of AMR to deliver audio products that ordinary people can afford and to date, they have been very well-received by the portable audio enthusiast community.
Disclaimer: This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.
Transparency and resolution
Compatibility with sensitive IEMs and demanding headphones
Balanced headphone output
Limited input options
Loud pop when it wakes from sleep mode (most noticeable with IEMs)
iFi Micro iDSD Signature
What Is It?
The Micro iDSD Signature is a powerful transportable DAC/amp that can play Hi-Res music files from your PC, phone or tablet. It has enough power to drive even the most demanding headphones. Furthermore, the Micro iDSD Signature can also be used as a preamp to feed active speakers or a power amp.
Although it is a desktop unit, the Signature can even be used on the move for up to 12 hours at a time thanks to its built-in battery. A clever gain-adjustment system makes the Micro iDSD Signature versatile and compatible with anything from very sensitive IEMs to power-hungry full-size headphones.
Packaging & Accessories
The iFi Micro iDSD Signature comes in a long, rectangular box with a grey cardboard sleeve. On the front and left sides are images of the unit. On the back (in teeny-weeny print) and right side, some features and specifications are listed.
The box proper is classic iFi style, just a clean white box with embossed silver iFi logos on it. Here’s what you find inside it:
iFi Micro iDSD Signature
Fabric storage pouch
USB Data cable
USB Type-C charging cable
2 elastic bands for stacking
3.5mm optical adapter
3.5mm to 6.35mm adapter
Silicone pad for stacking
The Signature chassis is aluminium with a stunning matte space blue finish. Considering the amount of power and options this thing has, the unit’s dimensions are impressively small. The front panel hosts (from left to right) a 6.35mm headphone output, a 4.4mm balanced headphone output, XBass switch, 3D+ switch, power switch/volume pot.
On the right side of the device is the USB Type-C port for charging. The left side hosts the Power Mode, Filter and IEMatch switches. Lastly, on the back of the unit are (from left to right) SPDIF Input, stereo RCA outputs and the USB digital input port.
As mentioned above, the unit is quite small and takes up very little space on the desktop. The build quality feels impeccable and very robust. I love the space blue finish that looks mature yet chic. But, for the most part, the Signature is unobtrusive and you’ll hardly even notice it sitting there.
Setting up the Signature on my Windows PC was simply a case of plugging in the 2 USB cables (one for data and the other for charging the battery/power). Windows detected it automatically and it was ready to go in a matter of seconds.
For maximum compatibility and versatility, the Signature comes with 3 different digital filters: ‘Standard’, ‘Minimum Phase’ and ‘Bit-Perfect’ for PCM files. It also has 3 amp stage settings, including ‘Turbo’ to ramp up the level of drive for current-hungry headphones and ‘Eco’ to dial down the power to suit high-sensitivity in-ear monitors and/or to extend battery life.
Moreover, Signature has the same IEMatch dynamic gain feature we saw on the Zen DAC. This adjusts the output level giving you a super-low noise floor and precise volume control for Ultra and High sensitivity IEMs. In addition, it can be turned off to deliver the maximum output gain for power-hungry headphones.
Equipped with RCA outputs, the Micro iDSD Signature can also be used as a preamp to connect to powered speakers or a power amp. Last but not least are the two switches on the front panel: The XBass is a purely analogue bass boost that turns up the fun factor with the flick of a switch. It adds more body and punch to bass notes without any noticeable degradation in sound quality.
The 3D switch enhances and widens the soundstage. This digital filter also works well with a minimum loss of stability on the centre image.
Internals & Output Power
The Signature has a dual DAC configuration via a pair of Burr-Brown DAC chips running in a custom “interleaved” configuration. These create four pairs of differential signals (two pairs per channel) for a lower noise floor, improved channel separation and finer musical detail and micro-dynamics. Furthermore, both PCM and DSD remain ‘bit-perfect’.
Furthermore, the Signature has iFi’s custom OV Series operational-amplifier for low noise and wide bandwidth, Panasonic OS-CON caps and direct-drive circuit design (no coupling capacitor).
When it comes to decoding, iDSD Signature can handle pretty much every file format you throw at it, including PCM up to 32-bit/768kHz and DSD512. Like most other recent DACs, the unit can decode MQA files as well. In regards to power output, the Signature is capable of up to a whopping 4100mW @ 16 Ohm load from the headphone output and >2V for the line output.
The main purpose of the internal battery is actually to utilize the ultra-clean and ultra-stable nature of DC power. This is especially useful if your computer has noisy USB ports. As an added bonus, it means the Signature can be employed on the go using battery power. Depending on the gain and power settings, the unit can play up to 12 hours of music thanks to its 4800mAh battery.
*Micro iDSD Signature was tested using Firmware 7.2
Setup used for testing the Micro iSDS Signature
The Signature was connected to a Windows 10 PC via USB. The music software used was Foobar2000 and MusicBee playing a variety of FLAC and DSD files. I also tested some playlists on Spotify Premium.
Headphones/IEMs used for testing include the FiiO FH3, FiR Audio 5×5, Beyerdynamic DT990 Pro and BLON B20. None of these is really demanding when it comes to power requirements, even the 250Ω DT990 Pro. Needless to say, the Signature was able to effortlessly drive everything to ear-splitting levels.
I have a few devices with Burr-Brown DAC chips in them and they all share some similar audio qualities. They have wonderful resolution, detail, transparency and effortless musicality. The iDSD Signature has excellent dynamics, a pitch-black background and superb imaging.
The first thing I plugged into the iDSD Signature was the FiR Audio 5×5. I was immediately impressed by the detail retrieval with this pairing. With the IEMatch set to “Ultra sensitivity”, there’s no audible hiss and the black background and instrument separation help the 5×5 craft a 3D holographic stage.
I love the clean, transparent but musical nature of this matchup. In Michael Jackson’s “PYT”, every element of the song is easy to distinguish and separate. The layering and imaging are simply top-notch.
Listening to Wang Wen’s “Stone Scissors” with the iDSD Signature and Blon B20 planar magnetic headphones, the amount of texture in the electric guitars and synths is mesmerizing. The song sounds gritty, dynamic and punchy.
The combination of the Signature’s instrument separation and the B20’s fast transients make this one of the best pairings I’ve heard for this particular track. As an aside, I listened to it again with the XBass+ turned on and was really impressed by the cleanliness and non-destructive nature of the awesome bass boost.
Singxer SDA-2 ($620)
The Singxer SDA-2 is a full-size desktop DAC/amp that comes equipped with an AK4497EQ DAC chip. In terms of size, the SDA-2 is enormous in comparison to the Micro iDSD Signature. That has some obvious benefits, such as the room to add a balanced XLR headphone out, balanced XLR line outputs. Furthermore, the SDA-2 has more digital input options and an OLED display. On the downside, the unit is enormous relative to the Signature and the entire chassis gets very hot.
Looking at the power output, the SDA-2 unsurprisingly has even more grunt with 30Ω 3480mW from the balanced output. Be that as it may, without a feature similar to IEMatch, the Singxer is not as ideal for sensitive IEMs as the noise floor is quite a bit higher.
When it comes to sound, the Singxer has a more muscular and robust sound. But the iDSD Signature has better separation and blacker background when used with headphones. However, the Singxer’s AK4497EQ DAC chip sounds starker and more confident when using its balanced XLR outputs with bigger speakers.
When comparing the two DACs with full-sized headphones, I was surprised at the similarity in tone. But the Burr-Brown in the Signature has uncanny resolving ability while still maintaining musicality. The Singxer sounds starker and a touch dryer in comparison.
The iFi Micro iDSD Signature is a truly impressive device. For something so small to have such a rich feature set, such power and audio quality is really something to behold. The build quality looks and feels premium. The internal components are extremely high-quality which is reflected in the essence of the audio that comes out of this thing.
Perhaps what’s most impressive about the Signature is its versatility. From the most sensitive in-ear monitors to full-size power-hungry headphones to powered speakers it’s got you covered. And to top it all off, you can pick it up and put it in your pocket to use on the go thanks to its built-in battery. This is one heck of a device and in fact, it’s the first product to receive our new recommended award. Kudos to the iDSD Signature!