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The Hegel H70 has won HighFidelity.com’s Red Fingerprint distinction which we previously awarded only to the Dynaudio Focus 260 floorstanding loudspeakers; Musica Ibuki USB DAC: JPLAY software player;and Pro Audio Bono Acrylic AP anti-vibration platform.

Review conditions. The Hegel amplifier sat upon the Acoustic Revive RST-38 anti-vibration platform. Unlike my standard convention, I did not use the Tara Labs Omega to connect the amplifier to the loudspeakers but the Norwegian Skogrand Cables SC Air. This turned out to be incredibly coherent with the Hegel sound. The electronics were connected with balanced XLR Oyaide AR-910 cables and unbalanced RCA Oyaide Tsunami Terzo RR. The digital coax cable was an Oyaide DR-510, the USB cable an Acoustic Revive USB-5.0PL. The Hegel amplifier was powered by a Sablon Audio The Robusto power cord.

Description. Front. The H70 is an integrated stereo amplifier with integral DAC (2xS/PDIF, 1xUSB). This cannot be seen at first glance as the fascia presents a classic purist appearance with only a volume and input selector knob. There are blue LEDs around the latter. In the middle there is a blue power LED and a mechanical power switch below. The enclosure is made of rigid steel panels whilst the fascia gets nicely shaped aluminum. The three feet—one in the back and two in the front—resemble Primare’s.

Back. The back panel tells us that we are in the 21st century. Here we find the mentioned digital inputs – USB, coax and Toslink. The first one runs an older receiver chip that only accepts signals up to 16 bits and 32/44.1/48kHz. The coaxial inputs accepts up to 24/192. I’m not sure whether the optical input is limited to 24/96. You select between optical and electrical inputs with a small switch between them. Next we have two pairs of gold-plated speaker terminals. They sit quite close together so it‘s best to use bananas. Then there’s the IEC socket with integral fuse. It is worth changing the latter to a Create Audio or similar. To the left we have three analog RCA inputs and one balanced. The RCA sockets are quite common and placed close together. This prevents cables with thick plugs like Acrolink. The XLRs have pin 2 hot.


Inside. The individual circuit sections of the H70 are arrayed a bit differently than usual in such product. In the front we have the heat sink for the output stage, the rest of the circuitry behind it. There are two PCBs: a big one for the amplification stages and a smaller one for the DAC. The RCA inputs are not gold plated, neither are the XLRs. Behind the latter we see two chips per channel. These NE5532 desymmetrize the signal. The inputs are switched by hermetically sealed relays. The signal running through small Nichicon caps is buffered by another NE5532. This is where the signal from the DAC arrives too.

The converter is based on the Burr Brown PCM1754 preceded by an AKM 4114 receiver. The 1754 is a medium-class 24/192 chip with mid-level S/N ratio of 106dB. The USB input is handled by the Burr Brown PCM2704 transceiver for its USB-to-S/PDIF conversion. I did not see a word clock anywhere where perhaps the needed frequencies are derived from the USB converter clock. The output stage is made up of transistors. In its input we can see blue multi-pin SE3909 ICs from Hegel. This is Hegel's proprietary SoundEngine, a circuit based on FET transistors. The H70 sports a new generation of this circuit. The current buffer is based on a pair of 2SA1943+2SC5200 Toshiba transistors per channel. They work in class AB class push/pull. Next to them we see empty space for another pair of transistors as probably used in the H100 model. This allows the increase of output power but aggravates issues with transistor matching. A single pair of transistors makes for the best push-pull configuration unless a company invests in pairing parallel working units, which costs a lot. Most components here are surface mounted except for a few resistors and capacitors. Volume control is via a black Alps potentiometer. The signal running to it is taken directly from the inputs using a long ribbon cable, then returned to the main PCB with another ribbon. The power supply is quite large. It is fed from a solid toroidal transformer with three secondary windings for the left and right channel power stages and preamplifier. Voltage filtering is achieved by four big bulk capacitors.

Remote wand. The amplifier is supplied with the RC3 remote working on Philips RC-5 codes. It is flat like a credit card and has membrane buttons. It is a system remote so we can also use it to also control the Hegel CD player.

Technical data (according to manufacturer):
Output power: 2x70W/8Ω
Volume, inputs and muting controlled by (optional) Hegel RC3 remote
Inputs: 3 x RCA, 1 x XLR
Digital inputs: 1 x USB + 2 x S/PDIF (coaxial or Toslink with hard switch on the back)
USB resolution: 16bit/48kHz, plug & play, no drivers needed
S/PDIF resolution: 24bit/192kHz
Analog frequency response: 1Hz - 100.000Hz
Signal to noise ratio: >100dB
Crosstalk: < -100dB
Distortion (THD): < 0.005% /50W/8Ω
Intermodulation: < 0.01% (19kHz + 20kHz)
Damping factor: > 1000
Output stage: four x 15A/150W high-speed bipolar transistors
Power consumption: 30W idle
Dimensions: 80 x 430 x 415mm (HxWxD)
Weight: 12kg

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