Review: iFi Audio iDAC + Gemini USB Cable
Mar 6, 2014 at 6:16 AM Thread Starter Post #1 of 2

ostewart

Reviewer at Sound Perfection Reviews
Formerly affiliated with HiFi Headphones
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I would like to thank Vincent at iFi for sending me these samples for review, I will try to write an honest review, this unit received well over 100hrs of burn-in.
 
The iDAC was tested with various headphones including the German Maestro GMP 8.35D + GMP 400 and also IEM's like the Westone UM Pro30 and Final Audio Design Piano Forte X-G. It was tested with and without the Gemini cable too.
 

 

 
Specs:
 
iDAC:
 
Specifications: 
Signal to Noise Ratio:>111dB(A)
Dynamic Range(-60dBFs):>111dB(A)
Crosstalk:<-102dB(1KHz)
Total Harmonic Distortion(THD):<0.005%
Jitter:Below measurement limit
Frequency Response:3Hz to 33KHz + 0.1dB/0.3dB
Headphone section: 
Output Power:>150mW (15Ω)
Output Voltage:>3.3V (>100Ω)
Signal to Noise Ratio:>97dB(A) (400mV/300R)
Total Harmonic Distortion:<0.003% (400mV/300R)
Output Impedance:frowning2:Zout):<1Ω
Power Consumption:< 2.5W
Dimensions:158(l)x68(w)x28(h)mm
Weight:193g(0.43lbs)

Gemini:
Compatible with High-Speed USB 2.0 (24Bit/192kHz and higher supported)
ConductorHeavy OHFC continuous cast copper
Insulation:Polyethylene
Shielding:Dual-shields
Impedance90ohms
ConnectorsiFi ‘FINAL’ USB connectors
Lengths/Weights:0.7m/220g (0.49 lbs)
1.5m/240g (0.53 lbs)
Warranty period:12 months
 
 
Packaging, Build Quality and Accessories:
Packaging is a simple white box, very elegant and simplistic, it has a picture of the iDAC on the front, on one of the sides it has a list of the features, on the other side a picture of the side of the iDAC, and on the back you will find all the technical information. This is just a sleeve, out of this slides a white box with iFi in silver pressed on the top of the box. Once you open this you are presented with the iDAC in a card in tray, and underneath this you will find the accessories included. The packaging is a little Apple-esque but I do like the simplistic design.
 
The Gemini box is similar to the other iFi products.
 

 

 
Accessories included with the iDAC are just the necessary, 4 adhesive rubber feet, a RCA-RCA cable and a standard USB cable.
The Gemini cable comes with a velvet pouch and also a standard USB to Mini USB adapter so you can use it with other DAC's too.
 
Build quality is good, the casing is aluminum, and feels great, I really like the finish, semi matte and it also doesn’t scratch easily which is great. The RCA's on the front are gold plated, the volume knob is custom built for iFi measuring better than the equivalent Alps pot. One gripe I have with the iDAC is the headphone socket which can feel a little loose sometimes, and sometimes audio cuts out if wiggled a lot.
 
The Gemini is superbly built, with a thich cable sheathed in nylon, metal housing on the connectors and 3 RF silencers, it is heavy and better suited to desktop setups because of the weight and also flexibility of the cable.
 

 

 
Info:
The iDAC is a 24Bit/192kHz full high definition DAC which uses a ESS Sabre Hyperstream DAC chip set. It uses asynchronous USB and Bit-Perfect signal transfer, it also has a built in 150mW headphone amp for when you don't want to take a whole rig out and about. It doesn't have any bass boost or 3D settings, but is just a pure DAC + headphone amp.
 
The Gemini USB cable is dual headed for separate transmission of the signal and the ground cables. It is dual shielded, uses heavy duty OHFC continuous cast copper cable, aluminium connectors for rigidity and shielding, and 3 RF silencers, the middle one is adjustable depending on the environment you're listening in. This cable adheres to the 90Ohm impedance specification and has very low resistance
 
Sound:
IDAC is a very capable DAC, using normal FLAC files it brings out so much detail. I usually can't tell a huge difference, but this sounds more detailed and cleaner than the ODAC I have had in the past. Also the amp section is fine for most portable headphones and IEM's on the iDAC. It portrays a good sense of air and space, obviously everything is track dependent, as it is a transparent DAC, using it with the iTube and iCan it truly is a very capable desktop rig, that is versatile too. The iDAC has perfect control and clarity, I think at its price point it offers an excellent quality DAC with a good amp section (albeit not powerful, 150mw) that is clean and crisp, the amp section is also neutral but not quite as spacious as the iCan/O2. The iDAC works well hooked up to any system, I've been using it with my xDuoo TA-02 tube amp and it still sounds great, I really enjoy the subtle details that the iDAC brings out in the music.
 
The Gemini USB cable, as mentioned before is a very well built USB cable, that's is great for a desktop setup. As for sound quality when using it with the iDAC I was impressed with the clarity of the iDAC, the cable does not magically make it sound 100x better, but does bring subtle improvements that contribute to my overall enjoyment of listening. Small improvements are slightly better soundstaging and air around the music, overall resolution is increased also. At least it is not the bottleneck in the system, that's for sure.
 

 
Overall:
So the iDAC is a very capable DAC with excellent transparency and detail, which allows you to match the amp to your headphones and not worry about DAC matching. The amp section is fine for easier to driver headphones, and even some more difficult to drive headphones, a few little improvements could be a 3.5mm line out, and maybe Coaxial/optical inputs, but in such a small package the iDAC is great as is. The Gemini is also a superbly built cable that adds subtle little improvements, that add to my overall listening pleasure. Whether it is worth the extra cash is up to the end user, but if you have an already excellent system and are looking for the bottleneck, don't rule out the cable, and with this excellent cable you know it won't be the bottleneck.
 
Sound Perfection Rating: iDAC: 9/10
                                        Gemini: 10/10
Tracks Used:
Skrillex – First Of The Year (Equinox) (320kbps MP3)
Paramore – Franklin (320kbps MP3)
Diana Krall – The Girl In The Other Room (FLAC)
Deolinda – Passou Por Mim E Sorriu (live) (ALAC)
Suicide Silence – Unanswered (FLAC)
Massive Attack – Angel (ALAC)
Eat Static – Dzhopa Dream (ALAC)
The XX – Crystalised (FLAC)
Funeral For A Friend – Bend Your Arms To Look Like Wings (ALAC)
Mumford & Sons – Little Lion Man (FLAC)
The Scene Aesthetic – Humans (259kbps MP3)
A Hero A Fake – Swallowed By The Sea (254kbps MP3)
Johnny Craig – Children Of Divorce (161kbps MP3)
Deadmau5 + Kaskade – I Remember (Caspa Remix) (320kbps MP3)
Black Uhuru – Utterance (ALAC)
We Are The In Crowd – Never Be What You Want (226kbps MP3)
Silverstein – Discovering The Waterfront (320kbps MP3)
Concept Of Thought – Our Thought (FLAC)
Nirvana – Something In The Way (Unplugged) (ALAC)
 
Mar 6, 2014 at 1:39 PM Post #2 of 2
From the iFi website:
 
A simple, yet effective illustration is the graph below. The Gemini cable adheres to the 90ohm specification of the USB transmission protocol exhibiting just a 1% deviation from the 90ohm impedance end-to-end (ie. connector + cable together). 

Other expensive audiophile cables by comparison, vary as much as 15% (or 78ohm-103ohm!) This one key parameter is often overlooked yet is essential to maximise the quality of the signal transfer. 

The Gemini D-H USB cable. This Twin is not identical. 
 
USB Cable Impedance Deviation
gemini_bank.jpg
Gemini Dual-Headed USB Cable adheres to the 90 ohm specification like no other.
 

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