ЦАПы — SOtM sHP-100

The sHP-100 is a combined USB DAC and headphone amplifier from SOtM, the Korean company known for digital audio products such as USB cards, network players and noise filters for computer audio. It is small enough for a desk and also works as a preamplifier, with a line output that can be fixed or variable, so it can feed an integrated amplifier or drive a power amplifier directly.

Key specs that matter

Conversion uses a Cirrus Logic CS4398 DAC. The USB input, handled by an XMOS processor in USB Audio Class 2.0, accepts PCM up to 24-bit/192 kHz and DSD64 and DSD128 with native ASIO support. Coaxial and optical inputs accept 24-bit up to 192 kHz through an AKM AK4113 receiver, and a 3.5 mm analogue input accepts up to 2 Vrms. The fixed line output delivers 2.7 Vrms at 47 ohms with THD+N below 0.002%. The headphone output reaches 2.1 Vrms at 13 ohms output impedance, with THD+N below 0.005%. Headphone power is 0.36 W into 30 ohms, 0.21 W into 50 ohms, 0.11 W into 100 ohms, 0.036 W into 300 ohms and 0.018 W into 600 ohms. Power input is 7 to 9 V DC. The unit measures 106 x 53 x 175 mm and weighs 1 kg.

Engineering and use context

The output stage is built around TI's LME49720 operational amplifier for the line stage and TPA6120A2 for headphones, a current-feedback chip designed for difficult headphone loads. Native ASIO support lets a Windows computer send DSD to the converter without conversion to PCM. Volume is set by an ALPS analogue potentiometer. The front knob combines volume, input selection with a short press and mute with a longer press, and four lamps show whether USB, coaxial, optical or analogue is selected. Two switches on the underside set the line output to fixed or variable and select low or high headphone impedance mode, the high setting raising voltage gain to four times for high-impedance headphones. The sHP-100 can run from USB bus power or from a 9 V DC supply, and SOtM offers its mBS-d2s battery supply as an option for isolation from mains noise. The 3.5 mm analogue input makes it usable as a headphone amplifier or preamplifier for a phone or portable player.

Pairing

The high-impedance mode suits 250 to 600 ohm headphones, while the low mode suits efficient dynamic and planar models. The variable line output can drive active monitors or a power amplifier directly, and SOtM's own network players connect over USB.

Alternatives

SOtM's sDP-1000 is the larger DAC and preamplifier of the brand.