|Hegel H100 Integrated Amplifier Review|
|Home Theater Power Amplifiers Integrated Amplifiers|
|Written by Todd Whitesel|
|Monday, 01 February 2010|
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Integrated amplifiers have come a long way in the last three decades. For years, they've had a reputation (deserved or not) as sonically inferior to separate preamp and power amp setups. Naysayers argue any component containing pre-amp and power amp modules is subject to cross-talk and bound to introduce unwanted noise and distortion into the signal chain. Still, an integrated's advantages – lower cost, space saving and fewer connections – make it a popular choice for music lovers faced with budget and/or room constraints. I believe most audiophiles would prefer stereo separates, but it's tough to go wrong with a well-designed integrated amplifier serving as heart of an audio system. And well-designed describes Hegel Audio's H100 integrated amplifier, a 120-watt designed to trounce distortion. Hailing from Oslo, Norway, the H100 is Hegel's entry-level amp. Though its $3,000 asking price may raise an eyebrow, there's more to this machine than meets the eye.
Audio manufacturers have long sought to reduce harmonic distortion that arises during output from an amplifier. When an original music signal passes through a transistor at a certain frequency, say 300 Hz, it will produce smaller amounts of harmonic multiples: 600 Hz (second harmonic), 900 Hz (third harmonic), 1200 Hz (fourth harmonic) – and so on – at output. High-order harmonics are particularly bad and can make music sound sharp and unpleasant. Hegel uses two proprietary technologies - SoundEngine and Fet-Tech - to eliminate all but the second and third harmonic. A cleaner music signal makes for more natural-sounding music. Hegel believes reducing harmonic distortion is only part of the picture and less important than dealing with Intermodulation Distortion or IM. With IM, the interacting signals are not related harmonically and can create a muddled blend of sound that changes the original signal's musical “story.”
Hegel asserts, “These IM distortion components are made in the amplifier stages and cannot be removed. The problem is usually worsened by the use of global feedback loops in amplifiers. The amplified signal is fed back to the input stage of the amplifier, and so the IM distortion is also sent through once more and amplified... Some manufacturers have no global feedback. That is fine and reduces distortion, but at the same time they lose damping factor – a key to keeping deep bass and good bass control.” To combat these issues, Hegel uses feed-forward instead of feedback, which is supposed to significantly reduce IM distortion and increase damping factor. According to the specs, the H100's distortion measures less than 0.005% at 50 watts in 8 ohms, while its IM is less than 0.01% (19kHz + 20 kHz). Additionally, the H100 sports separate DualPower power supplies for input and voltage gain stages and the amp's current output stages – more distortion-reducing measures.
The H100's minimalist design oozes Scandinavian coolness, in the best sense. The front panel is constructed from a solid aluminum bar that is glass-bead blasted and anodized; the top cover, side panels and knobs are brushed/blasted and anodized aluminum. The display is lit by a non-dimmable blue light, and it works fine, but the text abbreviations indicating selected source are difficult to read. For example, if CD source is selected, the text is displayed in lower case letters; for Auxiliary, it's “AU”: select Tuner and you get a strange capital T missing the left top half and a lower-case “u.” It looks like a Cyrillic acronym. At the least, all text should be standardized and upper-cased.
The 32-pound amp comes in black or pearl silver finish; my review unit was the latter and up close the front panel has a sparkly, flake-like appearance and gentle wave contour. Unassuming to the point of sleepiness, the H100 sports just three front controls – source selector knob, volume knob and power button. It definitely conforms to the Hegel philosophy of being easy to operate. The back boasts four unbalanced RCA outputs, one pair of balanced XLR outputs, a USB input and a Home Theater input. The latter is a maximum volume line level input with a permanent volume setting of 75 and for connection to a surround processor only with internal adjustable volume. The H100 delivers 120 watts into two channels at 8 ohms.
Hegel's RC2 remote is a classy, substantial unit made from a solid aluminum bar mirroring the H100's finish and design. I've complained before about manufacturers giving little thought to a component's remote, often offering cheap, unattractive plastic popsicles hardly befitting its master. If you cycle through the source options with the remote or control knob, you hit a “dead end” at the final option and have to bring it back instead of jumping forward to the beginning. That's a minor curiosity.
Despite its humble appearance, the H100 has several notable features such as the auto-volume fader. When the amp is powered on, the start-up volume always begins at 0 and gradually increases to a default volume of 30 (99 is the max). This safeguard protects speakers and amp from accidental surges and provides a reasonable starting point for listening. Want it louder? Turn it up! Several stand-alone DACs and A/V receivers sport USB ports but not many integrated amps. The H100 features a built-in USB sound card that connects easily to a computer without drivers or other software. Lastly, the H100 stands on a trio of feet that makes for easy leveling and ensures stable operation.