Integrated amplifiers — Cambrige Audio Edge A

The Edge A combines an integrated amplifier and a DAC and belongs to the Edge series, which Cambridge Audio launched in 2018 to mark the 50th year of the company. The project started in 2015, when owner James Johnson-Flint, managing director Stuart George and technical director Dominic Baker asked a design team of about 20 people to create three new components in time for the anniversary. The range takes its name from Professor Gordon Edge, a company founder who designed its first product, the P40 integrated amplifier of 1968. The Edge A reached US stores in June 2018 at USD 5,000, next to the Edge NQ preamp and network player at USD 4,000 and the Edge W power amp at USD 3,000, and the current US price is USD 5,999.

Key specs that matter

Rated output is 100 W RMS per channel into 8 ohm and 200 W RMS into 4 ohm. THD stays under 0.002% at 1 kHz at rated power into 8 ohm and under 0.02% from 20 Hz to 20 kHz. Frequency response reaches from below 3 Hz to above 80 kHz within 1 dB, signal to noise exceeds 103 dB referenced to full power, and crosstalk at 1 kHz is lower than -100 dB. Both balanced and unbalanced inputs present 47 kohm, with 380 mV RMS sensitivity on the unbalanced side. The case is 405 mm wide, 150 mm high and 460 mm deep, and it weighs 24.4 kg.

Engineering and use context

Class XA is a Cambridge Audio variant of Class AB that adds voltage to the output stage, moving the crossover point to a region where its distortion is outside audibility while keeping better efficiency than Class A. Two toroidal transformers are mounted in opposing symmetry so that their electromagnetic fields cancel. The circuit board is DC-coupled with the usual coupling capacitors removed, and a solid-state volume control keeps both channels at equal level. Parts were chosen in blind listening tests, the board layout is bespoke, and cooling relies on finned heat sinks inside a brushed aluminium case. Peak consumption is 1000 W and standby is below 0.5 W.

Pairing

Besides one XLR and two RCA line inputs, the Edge A accepts coaxial S/PDIF at 16 or 24 bit and 32 to 192 kHz, Toslink at 32 to 96 kHz, USB Audio Class 2.0 at up to 384 kHz PCM or DSD256, Bluetooth 4.1 with aptX HD at 24 bit and 48 kHz, and TV sound via Audio Return Channel. Outputs include two pairs of five-way speaker terminals and XLR and RCA preamp sockets, and the headphone jack is meant for 12 to 600 ohm models. A remote, Bluetooth antenna and Edge Link cable come in the box.

Alternatives

The Cambridge Audio CXA81 MKII is a lower cost integrated with a Class AB stage rated at 80 W into 8 ohm and an ESS ES9018K2M DAC.