Integrated amplifiers — Gato Audio DIA-250S

The DIA-250S from the Danish company Gato Audio combines a stereo power amplifier, a line preamplifier and a digital converter in one chassis. It sits below the DIA-400S in the Gato range, and a DIA-250S NPM version adds a network player module with Roon Ready streaming, Tidal, Qobuz and Deezer, Ethernet and Wi-Fi. The basic model starts at EUR 2,895, and the streaming module can be added later as an upgrade for EUR 600.

Key specs that matter

Output is 2 x 250 W into 8 ohm and 2 x 500 W into 4 ohm, with speaker loads of 4 to 16 ohm allowed. Voltage gain is 26 dB with 10 dB of headroom. Frequency response is 20 Hz to 20 kHz within 0.5 dB and 2 Hz to 70 kHz within 3 dB. THD stays below 0.01% at rated power and below 0.001% at the pre-out, and signal to noise ratio is above 110 dB. Analogue inputs are one XLR pair on gold-plated Neutrik sockets and two RCA pairs, with input impedance of 40 kOhm balanced and 20 kOhm unbalanced. Pre-outs are fitted as XLR and RCA and reach 13 V balanced or 6.5 V unbalanced. The case measures 325 x 105 x 420 mm and weighs 10 kg.

Engineering and use context

Gato uses class D amplification, fully analogue in operation and built as a PWM modulator with a single pair of MOSFET output transistors per channel, using International Rectifier technology. Each section has its own dedicated switch mode power supply. On the digital side a balanced-drive Burr-Brown PCM1794 converter receives every digital input after upsampling to 24 bit and 192 kHz. Coaxial and asynchronous USB inputs accept up to 24 bit and 192 kHz, the optical input up to 24 bit and 96 kHz, and an aptX 4.0 Bluetooth receiver takes streams from phones and tablets. A dot-matrix display shows the volume on the left and the input and sample rate on the right, and it can be switched off. The enclosure is nonmagnetic and offered in black or white gloss lacquer or in real walnut veneer, with custom top covers offered. Power draw is below 1 W in standby, 23 W at idle and 1,000 W at maximum.

Pairing

The rated load range means ordinary low and medium impedance passive speakers, as well as higher impedance designs, fall inside the specification. One RCA input can be configured as a home theatre bypass, turning the unit into a fixed-gain power amplifier for a surround processor. A 12 V trigger output and the line outputs allow an extra amplifier or a subwoofer with its own amp to join the system and switch on in step with the DIA-250S.

Alternatives

The Gato Audio DIA-400S offers a higher-output integrated design with converter in this range, rated at 400 W per channel into 8 ohm and built around the same class D approach.