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"Smooth, Full-bodied and Organic Sounding"

HiFiMan continues to create great sounding, affordably priced components for headphone aficionados. The company's EF5 headphone amplifier is the successor to the well-regarded EF1, and it fully lives up to expectations.

"Everything we expect from good valve circuits was in evidence," notes Srajan Ebaen in his May 2010 review for 6moons.com. "Color temperatures rose, tonal hues deepened, and that sense of 3D palpability so prized by tube fanciers increased noticeably."

"It's smooth, full-bodied and organic sounding," notes What Hi-fi? magazine. "Take a listen to Charlotte Gainsbourg's IRM set and we have no doubt you'll be impressed with the passion, intimacy and midrange fluidity on offer."

Two-Chassis Design with Dedicated Power Supply

The EF5 uses a two-chassis design that houses the power supply in a separate box to keep noise at a minimum. And we're not talking about a skimpy little 'wall-wart' AC adaptor, either. The DY-1 is a serious power supply designed specifically for the EF5 and includes a large toroidal transformer. Just like the EF5, it is completely hand built.

Hybrid Amplification Stage

But a dedicated power supply isn't the only thing that the EF5 has up its sleeve. It boasts high quality parts throughout its construction, but the most obvious detail to the build is the protruding 12AU7 vacuum tube, which contributes to this little jewel's warm and lifelike sound. The 12AU7 produces voltage gain as a cascode amplifier in the first stage.

The amplification stage is hybrid, though, combining the 12AU7 with a discrete component buffer stage. "The idea is to combine the sweetness of valves with the grip that they so often lack," notes England's What Hi-fi? magazine.

The output stage uses an OPA275 opamp, and tweakers will enjoy trying different opamps and tubes to alter the sound quality. But we're not saying that you'd want to! The EF5 works beautifully with a wide range of headphones and excels with HiFiMan's HE5LE 'phone. This powerful amp will provide a full two watts per channel into a load of 32 ohms.

The EF5 includes one pair of RCA inputs on the back panel and one headphone jack on the front panel. A high/low gain slider switch in front of the 12AU7 can be changed with a screwdriver to suit your headphones. Both the EF5 and DY-1 have an aluminum-extruded chassis.

• Hand-built headphone amplifier
• Separate-chassis DY-1 power supply with toroidal transformer
• Opamp: OPA275
• Tube: 12AU7
• Input: one RCA
• Output: one 1/4" headphone jack
• Detachable IEC power cord

• Frequency Response: 20-30K Hz
• THD+N: less than 0.2%
• S/N: more than 95 dB
• Input impedance: 50K Ohm
• Output impedance: 2–2K Ohm headphones
• Output signal strength: up to 15 Volts at 32 Ohm
• Dimension: 4.33" wide, 1.97" high, and 10.63" deep
• Shipping weight: 6 lbs

"Everything we expect from good valve circuits was in evidence, particularly once I'd rolled in a premium Full Music. Color temperatures rose, tonal hues deepened and that sense of 3D palpability so prized by tube fanciers increased noticeably. In parallel, general intensity improved to more approximate (but not equal) the presentation of my other earspeakers."

- Srajan Ebaen, 6moons.com, May 2010

"The EF5 lives up to all the valve stereotypes: it's smooth, full-bodied and organic sounding. Take a listen to Charlotte Gainsbourg's IRM set and we have no doubt you'll be impressed with the passion, intimacy and midrange fluidity on offer."

- What Hi-fi? magazine

"The Hifiman EF5 specializes in calming troubled treble waters. If you've got a pair of cans that can sound harsh at its top end, the EF5 will be able to smooth over any harsh bits, making them sound altogether more refined. This amp's perfect partner is the Hifiman HE5, and in that case the effect of the amp was particularly pronounced…"

Like any good headphone amp, the Hifiman EF5 also adds body to the sound, opening up whatever you pump into it to make everything sound that little bit more expansive."

- Andy Curzon, ElectricPig.co.uk, January 26, 2010

"I'll be recommending this amp to those of you looking for an entry level desktop amplifier with a full midrange and warm sound signature. It may not compete with the refinement of higher priced amps, but for the price, the EF5 gives a sound that's hard to dispute or not like. The power output is also very high, and the EF5 can drive the HE5/LE headphones, which are two very hard headphones to drive, with such an ease. At the price the EF5 is selling for, it's hard to not like it."

- Mike at Headphonia.com, August 18, 2010

Audio Advisor - HiFiMan EF5 Tube Headphone Amplifier