iFi Micro iDSD Signature Review: Pocket-sized DAC / Headphone Amp

iFi has just introduced a new Micro iDSD Signature DAC / Headphone Amp that features almost all the advantages of the Micro iDSD Black Label as well as a 4.4mm jack. Overall, the headphone amplifier is 177x67x28mm, the same standard size as the Black Label version, and is also built with an aluminum case. The difference with the Black Label version is that the iFi audio Micro iDSD Signature model is in Space Blue. It is also a new color for a range of products under the “Signature” series that will be launched in the future.

iFi audio Micro iDSD Signature Review

Although launched as a “pocket” device (with a rechargeable battery for portable needs), the Micro iDSD Signature is about the size of a DAC / desktop amplifier. Thanks to battery operation, the headphone preamp ensures a clean, stable power source, avoiding signal errors typically found in AC-powered digital to analog audio converter devices such as fluctuations, RFI / EMI interference.

The battery life of the IDSD signature is also very good, ranging from 6 ~ 12 hours depending on the headset you use and different music modes. When the battery is low, we can also plug it and at the same time use it to listen to music while charging.


The iFi audio Micro iDSD Signature is equipped with Dual-Core Burr-Brown DAC chips with True Native technology like all previous iFi products. A fully balanced setting in the professional headphone amplifier reduces background noise to a minimum as well as improves channel separation, enhances audio readout and clarity.

iFi audio Micro iDSD Signature Review

This new USB DAC support decoding of 32-bit / 768kHz PCM, DSD (maximum DSD512), and single / double-speed DXD. The MQA format is also perfectly supported.

It also has many other powerful technologies such as the iFi GMT (Global Master Timing) Femto Clock and Intelligent Memory Buffer, as well as the iFi GTO (Gibbs Transient Optimized) digital filter. The company also promises to add new digital filters according to future firmware updates to slightly change the sound quality.

The Micro iDSD signature uses premium components for the highest performance. The amplifier circuit uses the OV2028 and OV2627 op-amp with very low distortion, accompanied by a dedicated audio capacitor combination of TDK C0G, Panasonic ECPU, and Panasonic OS-CON, with MELF film resistors and production leads produced by Taiyo Yuden and Murata. The signal path from the pre to the power layer of the iDSD Signature retains the famous Direct Drive Servoless design of iFi, without using a cascade capacitor in the signal path.


The iFi audio Micro iDSD Signature DAC / Headphone Amp has various filter settings including Standard, Minimum Phase, and Bit-Perfect for PCM format, and Standard Bandwidth, Extended Bandwidth, and Extreme Bandwidth for DSD format. The working mode of the amplifier is also categorized into Normal, Turbo, and Echo to customize the power/gain level to suit different usage conditions.

iFi audio Micro iDSD Signature Review

In addition, the USB DAC also has its own optimized mode for high-sensitivity IEM headphones named IEMatch by iFi. IEMatch mode has 2 options, High Sensitivity, and Ultra Sensitivity, to customize the most suitable for each headset, especially in-ears with high sensitivity and low impedance.

It would be a mistake not to mention two features that are always present in iFi amplifiers: XBass+ and 3D+. Users can completely enable or disable them depending on their listening preferences. XBass+ will help increase the bass range for low-bass headphones, while 3D+ will simulate the sound space for better listening to stereo recordings, in other words, the soundstage of the headphones will help widen and create the feeling of listening to music from the speakers.


At the rear of the device are 2 digital inputs including USB-A and S / PDIF, included with optical adapter accessories. The USB-A port of the device has a male-end design that plugs directly into other devices or with adapters for mobile devices. The RCA jack is still there to plug into the powered speaker, amplifier, or passive speaker, allowing the Micro iDSD Signature to work as a discrete DAC. When working in this mode, we can still use iFi 3D+ technology. The front of the device is a streamlined volume knob, XBass+ and 3D+ switches, and two 6.3mm single-ended and 4.4mm headphone ports.

iFi audio Micro iDSD Signature Review

This design is very welcome because it will be compatible with current hi fi headphones models that have switched to using 4.4mm pins. Both headphone jacks use S-Balanced technology to improve the sound performance of headphones with a balanced jack. Even with headphones using single-ended jacks, S-Balanced technology will help reduce crosstalk and distortion.


Let’s talk about the sound experience of the Micro iDSD Signature, one pair of headphones that we pulled out while listening to this that we recently reviewed a Sennheiser HD 560S.

iFi audio Micro iDSD Signature Review

The sound of these is typically a little rounded out and more low end focused, but we felt that the high mids and the top end really came alive through this device in a way that was really nice and refreshing. Frequencies here had more resonance than we typically find with these and the amount of detail in the stage was really high, very wide, and very open.

Turning on the 3D+ feature, adding an extra sharpness to everything that really gave these an elevated quality, especially with live music. Bebe Rexha feat. Doja Cat – “Baby, I’m Jealous” sounds wonderfully rich and layered with a huge array of instruments, while the Xbass switch tastefully deepens the soulful low end and gives it an extra bit of weight and punch.

As far as Hi Fi earphones, we have the FiiO FA9 since it is a unit that’s fairly new and that we had reviewed. When we ran these through the new Micro iDSD Signature, we actually found it to alter the signature a decent amount. We flipped on the high sensitivity mode for a comfortable nominal gain and overall found that this added a decent amount of depth to the soundstage.

The XBass+ mode performed the same deepening of the low end which sounded decent as well, but we found the 3D+ switch to be less successful in this instance, as it just muddled the details somewhat.

Final line

The IFi Audio Micro iDSD Signature is a fixed pocket DAC / Headphone Amp whose battery life is also very good and can be proven thanks to its ability to drive practically anything. The construction of the DAC is good and looks solid, excluding the switches, and with a little attention you can carry it everywhere without problems

The compact Headphone Amp, however, also defends itself well on the desk at home thanks to the possibility of powering it directly from USB and the RCA outputs that can be set both with a fixed output in case you want to combine it with a standard or variable system to connect monitors or an amplifier.

It can be purchased through Amazon.com for $649.99. Or you can also see our FiiO BTR3K review, Bluetooth stereo receiver model at a significantly lower price, and a comprehensive upgrade with the DUAL Bluetooth DAC design, which upgrades the USB DAC chip to the latest generation of AKM with the 3.5mm and 2.5mm balanced outputs.

About Ankeet Solanki

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