Integrated amplifiers — Phaze Audio Volt

The Volt is an all-in-one integrated amplifier from Phaze Audio, a brand that also sells the Diana mk2, Adelle, Julia and Celine turntables and a range of cables. It combines a DAC and file player, a preamplifier, a Class AB power amplifier and a headphone amplifier in one case, and it is priced at USD 529. The Diana mk2 turntable costs USD 249 and the Adelle USD 469, which places the Volt at the top of the brand's price range.

Key specs that matter

Output is 50 W into 8 ohm and 80 W into 4 ohm, measured at 1 kHz and 1% THD. Signal to noise ratio reaches 100 dB A-weighted, frequency response is 20 Hz to 100 kHz within +1 and -3 dB, and gain is 39 dB. The DAC is an MS4344, Bluetooth 5.0 runs on an ATS2835 chip and volume is handled by an NJW1194 control IC. Inputs are USB Type-C 3.1 for a computer, HDMI ARC for a television, Bluetooth and a microSD slot that takes cards of up to 128 GB, and a 3.5 mm headphone socket sits on the front. There is no analogue line input. Power comes from a 300 W toroidal transformer, maximum consumption is 300 W and the unit selects 115 V at 60 Hz or 230 V at 50 Hz automatically. It measures 430 x 345 x 77 mm and weighs 6.6 kg.

Engineering and use context

A Class AB output stage runs with a small bias current, so it avoids the switching distortion of pure Class B while producing less heat than Class A. The toroidal transformer has a low stray magnetic field and a compact shape for its power rating. The NJW1194 is an electronic volume and tone control chip that is set digitally, which is what allows volume, bass and treble to be adjusted from the mobile app as well as from the supplied remote. The app also selects the source. The USB-C input makes the Volt a sound card for a computer, and the microSD slot plays music files directly without any source device. HDMI ARC takes sound from the television's ARC socket, so the TV needs an ARC port for this connection. Because every input is digital, a turntable or cassette deck cannot be connected directly and would need an external converter with a digital output.

Pairing

The rated power suits efficient bookshelf or compact floorstanding speakers in a room of about 20 m2, and the higher output into lower impedance shows the amplifier can drive lower-impedance models. A computer, a television and a phone can all stay connected, with the app switching between them.

Alternatives

Phaze Audio makes no other integrated amplifier, as the Volt is the only amplifier in its catalogue.