NuForce HAP-100 Headphone Amplifier/Preamplifier


Equipment report
Headphone amps and amp/DACs
Nuforce HAP-100
NuForce HAP-100 Headphone Amplifier/Preamplifier

To better understand the foregoing comments, try listening to the HAP-100 with a variety of headphones on a bellwether track such as “Angel of Darkness” from Hot Tuna’s Steady As She Goes [Red House Records]. This enjoyable but non-audiophilegrade recording presents midrange content that is energetic and somewhat prominent to begin with, so that the need for midrange and upper midrange neutrality and for counterbalancing bass weight and body becomes critically important. The HAP-100 displayed its signature sonic virtues on “Angel of Darkness” when driving the Sennheiser HD-800s, but with harder-to-drive ’phones the amp often pushed Jorma Kaukonen’s vocals and electric guitar too far forward in the mix, giving them a borderline shrill quality. Similarly, when driving difficult loads, the amp undercut Jack Cassady’s normally vigorous-sounding, syncopated bass guitar lines, making them sound thin and insubstantial, thus robbing the song of its low-frequency foundation.

For comparison purposes, I tried the same track with the same group of test headphones, but using competing amps from CEntrance (the DACmini, $799) and Burson Audio (the Soloist, $999). What I learned was that both of these admittedly more costly competitors could match or surpass the HAP-100’s sonic strengths, while consistently delivering more balanced tonal response across a broad range of headphones.

All things considered, the NuForce has much to offer when it is used with in-ear monitors or with the right full-size headphones. But the fact is that the amp does appear to be load-sensitive, meaning that it would be a good idea to try the HAP-100 with your preferred headphones before making a purchase.

HAP-100 as a Preamplifier

I tested the HAP-100’s capabilities in a high-end system comprising an Oppo BDP-93 NE (NuForce Edition), a pair of NuForce Reference 9 V2 SE monoblock amps, and a pair of PSB Imagine T2 floorstanders. I also had on hand a sample of NuForce’s exotic, two-chassis Reference P-9 preamplifier ($3150) to use for comparison.

Very early on, I came to think the HAP-100 was well suited to its role as a preamplifier. I say this because the HAP-100’s output capabilities seemed well matched to the task of driving power amplifiers, thus allowing the NuForce’s best sonic qualities to shine through while minimizing possible sonic weakness. The result, then, was a preamp that, while not perfect, offered really impressive performance in light of its price.

To observe some of the HAP-100’s strengths in action, check out the track “Satori in Chicago” from Noah Wotherspoon & The Stratocats’ Buzz Me [APO Records], which is a very well recorded, jazz-inflected, electric-blues cut. Wotherspoon demonstrates a command of all of the usual Fender Stratocaster pyrotechnics plus a few of his own, so that the song offers a masterful display of soulful electric-blues guitar chops. But the song also offers something more—namely, the unmistakable sound of a highly skilled band that is absolutely locked into its collective groove. The NuForce does its part in several ways, first by revealing the leading edges of transients in a clear, powerful, and incisive way, and then by focusing on tonal purity and inner details. As a result, Wotherspoon’s guitar really does sound like a Stratocaster merrily howling away through a fine guitar amp, while the electric bass has the visceral, deeply grounded drive of the real thing. But perhaps one of the biggest treats of all is the HAP-100’s rendition of the drums, which have a just-right amount of snap and “pop,” and of the hi-hats and cymbals, which shimmer with rich layers of delicate, understated detail. This is awfully fine sound from a $595 preamp.

How does the HAP-100 compare to the far more costly Reference P-9. In simple terms, I think many listeners would report the two preamps sound more alike than not, though discerning listeners would find small but significant differences. First, the P-9 offers smoother and more grain-free mid and highs. Next, the P-9 offers better-weighted and more powerful bass, though in fairness the HAP-100 sometimes seems to offer a more taut low-end presentation. Finally, the P-9 offers a heightened degree of threedimensionality— perhaps because it is even quieter than the HAP-100 and provides superior resolution of lowlevel details.

Collectively, these differences become apparent on a track such as the “Aphrodite” movement of Robert Paterson’s The Book of Goddesses [American Modern Recordings], which highlights flute, harp, and percussion as captured in a reverberant recording space. The HAP-100 gave a good, clear, detailed rendition of “Aphrodite,” but the P-9 makes the three-dimensional character of the recording space (and of the instruments’ interactions within the space) much more apparent. Still, the important point to bear in mind is that the HAP-100 captures a significant percentage of the P-9’s sonic goodness and overall character for less than one-fifth its price.

Summing up, I would say the HAP-100 offers terrific value as a preamplifier; it is in no way embarrassed in the company of more expensive units. It is quiet, detailed, and well defined, and come with a handy remote that’s a joy to use. Moreover, the HAP-100 is a thoroughly viable headphone amplifier, one that’s at its best with in-ear transducers, but can also give highly satisfying results with some (though not all) of today’s best full-size headphones. Viewed as a complete package, the HAP-100 offers an awful lot to like at a down-to-earth price.


Inputs: Four stereo analog inputs (RCA)
Outputs: One variable-level stereo analog output (RCA), one 1/4-inch headphone jack
Accessories: Power cord, full-featured remote
Frequency response: 20Hz–20kHz, +0/-0.1dB
Distortion: <0.002% @ 20Hz–20kHz (3V RMS output at RCA jacks)
Signal-to-noise ratio: >100dB
Preamp output: 7.8V RMS, RCA, maximum
Headphone output: 5.2V RMS, Hi-Z, maximum 5.1V RMS @ 300 Ohms, 1.81V RMS @ 32 Ohms, 0.91V RMS @ 16 Ohms
Weight: Not specified
Dimensions: 8.5" x 1.875" x 10"
Price: $595

NuForce, Inc.
382 South Abbott Ave.
Milpitas, CA 95035
(408) 890-6840, East;
(408) 240-0746, West

Full-Size Headphones: Audeze LCD 3; Fischer Audio FA-002W High Edition; HiFiMAN HE- 400, HE-500, and HE-6; and Sennheiser HD-800
Custom-Fit In-Ear Monitors: JH Audio JH 16 PRO s; Ultimate Ears In-Ear Reference Monitors and Personal Reference Monitors; and Westone Elite Series ES -5 Monitors
Headphone Amps, Amp/Preamps, and Amp/DACs: Audio Electronics by Cary Audio Nighthawk, Burson Audio Soloist, CEntrance DACmini, and HiFiMAN EF-5 and EF-6.
Sources: AudioQuest DragonFly DAC with Mac Mini, CEntrance DACmini with Mac Mini, NuForce-modified Oppo BDP-93SE universal/Blu-ray player, and Oppo Digital BDP-95 universal/Blu-ray player
Preamps: Burson Audio Soloist, NuForce Reference P9
Power Amps: NuForce Reference 9 V3 Special Edition monoblocks
Loudspeakers: PSB Imagine T2
Interconnects/Speaker Cables: Nordost Blue Heaven and Ultralink
Room treatments: RPB Binary Absorber/Diffsorber panels