Hifiman EF400 Review

In this article, we review the HiFiman EF400. It’s the latest desktop DAC/AMP from the Chinese brand, available for $599,99 USD.

Disclaimer: the HiFiman EF400 was sent to us, free of charge, by the brand in exchange for our honest opinion. 

About HiFiman

Founded in 2007 by Dr. Fang Bian, Hifiman has become, throughout the years, one of the most renowned hi-fi brands – pretty much like FiiO, who began around the same time.

An unexpected success, as the manufacturer succeeded in the audacious challenge of bringing orthodynamic transducers, back to the forefront of the scene. A real challenge, taken up in less than a quarter of a century, especially since Hifiman did not benefit from the aura of a BeyerDynamic, or AKG, true secular institutions.

If the brand was located in New York during its beginnings, it quickly moved to China, and more precisely to TianJin, to be closer to its production plants. A choice that allowed Fang and his team to expand their catalog, while fixing some early mistakes – hello HiFiman HE-400!

But, before headphones, HiFiman also produced DAP – who remembers the HM-801 and HM-601 ? – followed pretty quickly by DAC. The quirk? Almost all of them used R2R DAC at the beginning, instead of the traditional delta-sigma setup favored by… everyone else? 

A difference nurtured by the brand, which keeps on trying, putting R2R DAC in everything they can, from DAP like the R2R Streaming HD – a VERY quirky one – to the new HiFiman EF400 we are about to review: the first non-vacuum tube amplifier produced in a while, doubled as a… R2R DAC!

Design & Build Quality

Casing

Big and bulky, the HiFiman EF400 is a pure desktop amp. 

Sure, compared to its predecessor, the EF-6 – a Class-A behemoth… for headphones! – the new DAC/Amp looks almost small, or at least reasonable. Yet, compared to my SMSL DO200 + HO200 combo, the EF-400 footprint is easily twice bigger on my desktop. Size-wise, the HiFiman EF400 is 246.5mm long, 228mm wide, and 61mm tall, a moderately large body that also weighs quite a bit, 3kg. Thankfully, the solid chassis allows you to put various things on top of the DAC, like a monitor or your laptop – even if I would not recommend the latter, for heat dissipation issues.

Entirely made of aluminum, the HiFiman EF400 looks and feels like a real desktop device, something that’ll become the centrepiece of your setup. A feeling reinforced by the big knobs on the front panel, supplemented by no less than four headphone outputs (two balanced + two single-ended), two line outputs (XLR + RCA), and two USB inputs – yes, this is a PURE DAC.

A big baby, packing a lot of features, as we’ll see later…

Build Quality

It’s common knowledge, in this regard, HiFiman products can be hit or miss. Sometimes you get a device that can outlast you, and sometimes… it’s complicated.

Thankfully, the HiFiman EF400 seems to belong to the first category and is absolutely flawless in terms of build quality. The silver front plate fits impeccably upon the black case, all the knobs offer a perfect grip, and after weeks of plugging/unplugging my headphones, none of the ports show any sign of wear.

A good example? When I took the DAC out of his box, I checked if there was a Voltage Bias, and yes there was. Then, I read it wrong and inadvertently put the EF400 in 110V, instead of 220V, which inevitably broke the device… or so I thought! All I had to do, was change the fuse, put back the DAC in 220V and up we go!

Add to that a long-course volume potentiometer, a four-stop gain selector, and a very nice led set, and this DAC is easily on-par with my Cayin setup, or SMSL duo. It feels premium on and out, and for whoever wants a flawless device, with its matte-black frame, the HiFiman EF400 is a sure choice.

All in all, it’s a very solid piece of work, and I can’t say bad things about the EF400 in this regard.

Comfort and Specifications

Daily use

As I expected, the HiFiman EF400 is extremely simple to use. Plug it into your computer/phone/DAC, or any digital source, insert your headphone jack, and you’re good to go. 

It’s a pure DAC, with no inputs other than USB-C and USB-A, so if you expected to connect your source via Optical or Coaxial… you’re out of luck. Personally, I prefer this approach, and I’d gladly ditch every other port, for a sole USB-C, as you can carry almost any kind of files and stream through this single port.

There were no issues with my MacBook, or my PC, each time, the HiFiman EF400 was immediately recognized as a DAC. On Windows, I had to wait a minute, until the OS got the right driver but after that, it worked flawlessly. The same goes for my iPhone, connected with the classic ddHiFi TC28i and a regular USB-C to USB-C cable, the DAC was directly identified by my phone.

On the quirky side, I was surprised by the four different gain settings available – NOS (no oversampling) and OS (oversampling):

• High Gain NOS
• High Gain OS
• Low Gain OS
• Low Gain NOS

Four different headphone outputs, enough to plug all and every headphone you shall have:

• Jack 6.35mm 
• Jack 3.5mm
• Jack 4.4mm Pentaconn
• XLR 4-Pins

. And bonus point, the HiFiman EF400 also offer two line out:

• a classic RCA, single-ended
• a dual XLR, balanced 

Note that those two ports work as a fixed line-out, as they come directly from the R2R DAC board. Speaking of that, let’s take a quick look at the specs now!

Specifications

As stated before, the EF400 uses the same R2R architecture DAC you can find in their DAP: the HIMALAYA DAC. 

In case you’re not familiar with R-2R DAC, this kind of digital to analog converter uses two sets of precision resistors, to convert a digital binary number into an analog output signal, proportional to the value of the digital number. Needless to say that compared to your usual Sigma Delta DAC, they can be quite bothersome to produce, and expensive.

So, HiFiman took a different approach and tried to mix the best of both worlds. Something they seem to achieve with… an FPGA chip – once again! – that takes place in the center of the R2R DAC module. This chip, thanks to the brand’s unique algorithm, can reduce electrical interference between the various peripheral components, since – by essence – R2R may be greatly affected by those electric gremlins.

On paper, the dual set – one per channel – offers high-end specs with :

• full PCM decoding up to 24bit / 768kHz, 
• excellent Signal to Noise ratio (120dB)
• low total harmonic distortion (0.022%)
• and super low power consumption (20mW !)

A great pack on paper, that should be able to compete with the best AKM/ESS/Texas-Instruments DAC, with a sound signature, only found on R2R chipsets.

For the power section, HiFiman installed a full-discrete circuit, with large 30 000uF capacitors, and the same dual-channel architecture, for utmost performance. The four-channel differential structure features a maximum output of 10.7 Vrms on a 36ohm load, so you should be able to drive any headphone with ease (spoiler alert, it did)

Finally, you can spot a MASSIVE oxygen-free copper wire toroidal transformer, which might be the main reason why the HiFiman EF400 weighs so much. And, for the nerds out there, here are the full specs.

Technical specs

• Type: USB DAC + headphone amplifier
• Model: HiFiman EF400
• Chipset: 2x HIMALAYA R2R DAC
• Frequency range: 20 – 20 000Hz
• Compatibility: PCM up to 24bit/768kHz 
• SNR: 120dB (A Weighted)
• THD: between 0.002% and 0.004%
• Output power: up to 4400mW per channel
• Size: 246,5mm x 228mm x 61mm
• Weight: 3080g
• Outputs (headphones): 3.5mm TRS / 6.35mm TRS / 4.4mm Pentaconn / XLR 4 pins 
• Outputs (line) : RCA / XLR
• Inputs: USB-C / USB-A
• Price: $599

The article continues on Page Two, after the click here