Until this moment, until 2017 January 12 around 9PM, want to know what my most recommended portable battery-powered headphone amplifier was? I’ll tell you. It was Vorzüge’s PURE II (both versions). I can get it to eat up an overdriven Chord Mojo signal of 122dB and spit back around 120dB. At stable volumes, it measures between 118-119dB. It is an amazing amp whose load stability, signal to noise ratio, THD, IMD, and dynamic range are matched by almost no one.
Read moreRMAA: Cozoy TAKT 24-bit
RMAA: nuforce uDAC5 24-bit
The uDAC5 goes for peanuts. It is well built, nicely branded, and compact. It converts USB signals to RCA stereo and coaxial SPDIF for outboard DACs and amps. It gets plenty loud, too: posting absolute volume levels roughly in the neighbourhood of an AK380. At those levels, however, IMD, THD, and stereo crosstalk numbers ramp up beyond reason. Its loudest stable volume is about a half decibel louder than an iPhone 6’s maximum, which is enough for me. If your iPhone is behind a EU volume cap, the uDAC5's power will surprise you.
Read moreRMAA: Linear Tube Audio MZ2-S 24-bit
The Linear Tube Audio MZ2-S, which I originally mistook for the microZOTL2,0, is a brilliant in/out valve amp whose design/performance niggles are minimal. According to Linear Tube Audio, its biggest design niggles: depressed power button, and attenuator noise, have been fixed. I can neither confirm nor deny this.
Read moreRMAA: Apple iPhone 7 24-bit
Last week my iPhone SE came in. And though she ordered it late, so did my wife’s iPhone 7. While the SE is gloriously understated, and wieldy, the 7 is a return to what I consider Apple’s most horrific modern design. Its largest makeover is the removal of a headphone jack. Next is the smoothing out of its camera hump, a consequence of which is that iPhone 6-compatible cases half cover up the iPhone 7’s camera and flash superstructure.
Read moreRMAA: Apple's Lightning to 3,5 mm Headphone Jack Adapter 24-bit
Purchased separately to the iPhone 7, this adapter costs 9$ USD. It hisses less than an Astell&Kern AK70 and outputs a stabler signal under load than both the AK70 and an iPhone 6. It sustains quality signals under load better than many DAPs and most iPhones I’ve tested in many years, all while spitting output voltage similar near the level of an iPhone 6.
Read moreRMAA: Cozoy REI 24-bit
Considering Astrapi’s abortive attempt at audiophilia, I expected little of REI. Instead, COZOY have corrected every one of Astrapi’s egregious faults. They are: REI outputs no more hiss than an iPhone 6; its lowest volume levels jive with sensitive-eared listeners; it outperforms the iPhone 6 in a number of key metrics; it gets loud without turning its signal to mush.
Read moreRMAA: Astell&Kern XB10 24-bit
At the top of every every audiophile’s wish list should be the democratisation of headphone output performance. Think Chord Mojo, Theorem 720, ALO Continental. For good reason - hiss, poor output impedance, connection problems, and general shyte performance - Bluetooth DAC/amps rarely make the cut.
Read moreRMAA: Astell&Kern AK70 24-bit
Marketing copy worthy of blooper reels is one of Astell&Kern’s fortes. And, Music Friend In My Pocket, AK70, is the cringingly, suggestively ugly even by AK standards. Bravo. Despite, this, the AK70 itself is handsome. Sure, its Korean edges will draw blood. But it is shorter than an iPhone 5 and not much larger than an original AK120. Get a case for it. It will fit in your pocket.
Read moreRMAA: Audient iD4 24-bit
Adjusting input levels, and volume is easy breezy thanks to fine-tuned DAW and plug-in controls. Its headphone amp being poorly suited to low-resistance earphones, returning anomalies in frequency response, THD, IMD, and stereo crosstalk. Most of the anomalies smooth out by the time portable or monitoring headphones are plugged in. And, iD4 spits perfectly matched volume into both channels at all volume levels, not to mention trace amounts of background noise. I’ve yet to go deep into its microphone amps, but after digitising test signals from Mojo, I am relatively convinced of its recording fidelity - considering its price, and ostensible market. Stereo crosstalk numbers aside, that is.
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