Hegel H90 integrated amplifier

Integrated amplifiers
Hegel Music Systems H90
Hegel H90 integrated amplifier

I’ve made no secret of the enjoyment I’ve extracted from the Hegel H80 integrated amplifier. The starter amp from the Norwegian electronics expert has fought above its weight category for the last four years, often being the cheapest link in an otherwise very expensive chain. The H90 replaces the H80, and improves on its predecessor in almost every way, but without incurring a price penalty. And, although they ostensibly look the same, share a similar chassis, and occupy the same space in the catalogue, they couldn’t be more different.

Hegel has changed a lot in the intervening years between the H80 and H90. The H80 was one of the first of the company’s ‘refreshed’ line, featuring improved versions of the company’s long-standing ‘SoundEngine’ circuit design, but subsequent developments have radically improved the performance of Hegel’s amplifiers still further.

Hegel is big on nomenclature, and the H90 bristles with several of the company’s key technologies, encapsulated in pithy names like ‘DualAmp’ and ‘DualPower’, alongside the aforementioned ‘SoundEngine’. It’s worth looking at Hegel’s own documentation to get more loquacious descriptions than we can muster here, but in essence, ‘DualAmp’ technology separates the voltage and current gain stages into two distinct amplifier modules, while ‘DualPower’ relates to provision of discreet power supply feeds to the input/voltage gain stage of the preamplifier section, and the current output stage of the power amplifier stage, with separate taps from the transformer feeding independent power supply sections. ‘SoundEngine’ meanwhile is a form of local error cancelling in place of global feedback, which in sound quality terms makes an amplifier with Class AB efficiency and something close to Class A performance. These all combine to create Hegel’s ‘Organic Sound’ voicing, which is unconnected to a specific engineering concept, and more to do with listening tests and the generalised application of technology to ensure the amplifier sounds as natural as possible. We’re not reinventing the wheel here, and this approach to amplifier design works well for other companies without the need to create names and little orange logos for each aspect, but it bespeaks of the application required to make an amplifier sound good.

The new DAC section still includes conventional S/PDIF and USB interfaces, but now brings Ethernet network streaming to the party. This remains a 24-bit, 192kHz PCM-based DAC; those seeking a more DSD-related performance from Hegel should look at one of the two DACs made by the company, and MQA is presently not in Hegel’s line-up at all. This section also comes in for its own share of the nomenclature: ‘USB’ is – as you might guess – discussing the USB input, however Hegel’s pin on this is to have effectively its own custom sound card at the USB input. Meanwhile, the company’s ‘SynchroDAC’ system is an internal jitter and synchronised upsampling system, in direct opposition to the now more commonplace asynchronous conversion found in most USB converters. Hegel suggests asynchronous technology converts jitter into amplitude errors within the signal, thereby undermining the digital data on input. 

There are two radical components to the H90 when set against the H80. First, the front panel is now a composite instead of metal, although unless you plan on using the H90 for a game of ‘guess the material’ this should be about as relevant to the performance as the logo on the cardboard box used for delivery. Then, the H90 is actually less powerful than its predecessor, on paper at least. This is now a 60W amplifier where the H80 achieved 75W per channel. Paradoxically, the H90 is a more powerful amplifier in terms of what it does with those 60W, as evidenced in part by the amplifier’s high damping factor of more than 2000, effectively doubling the power supply ‘stiffness’ of its predecessor. In practice, the only real omission between H80 and H90 is the removal of the XLR input for pseudo-balanced operation. As the H80 sounded slightly better through single-ended phono sockets anyway, getting rid of these connections in favour of leaving just the original two RCA inputs and one output is no big loss at the price.

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