Предусилители — Soulution Audio 326 preamplifier

The 326 preamplifier belongs to the updated second generation of the Series 3 range from Swiss manufacturer Soulution, a lineup that also includes the 312 stereo amplifier, the 331 integrated amplifier, the 350 phonostage and the 360 DAC. According to the company, the new Series 3 products take over several technologies and designs from the 5 and 7 series. Soulution states that a preamplifier should only amplify or attenuate the music signal without changing it, and the base unit handles analogue sources, while optional modules add a moving coil phono stage and a DAC.

Key specs that matter

Four analogue line inputs are fitted - a pair on XLR sockets and a pair on RCA - alongside one XLR and one RCA output. The input impedance is 5.8 kOhm balanced and 4.9 kOhm unbalanced, and output impedance is 10 ohms balanced and 5 ohms unbalanced. Gain covers -79 to 0 dB. Soulution optimised all small-signal circuits of the new generation for a bandwidth of at least 2 MHz at -3 dB, which cuts phase shift in the audio band compared with the earlier 326 design. Phase shift at 20 kHz stays under -1.5 degrees, THD is below 0.0001 percent and spot noise is below -140 dBV per root hertz. Mains range is 100 to 240 V at 50 or 60 Hz, with consumption under 0.5 W in standby and about 30 W in use. The case measures 430 x 350 x 142 mm and weighs about 10 kg.

Engineering and use context

An unbalanced circuit keeps the number of parts in the signal path low, and the two channels are physically separated inside the chassis. A coupling capacitor of audio grade stops DC from reaching downstream equipment. Volume is set by relays switching precision metal foil resistors in 80 steps of 1 dB. While the level changes, an IC-based secondary path takes over to prevent clicks and pops, and the signal returns to the resistor ladder once adjustment ends. The optional phono module uses a two-stage active and passive RIAA network with 60 dB of gain and an MC load adjustable from 10 to 1260 ohms. The optional DAC module offers SPDIF, AES/EBU, USB and network inputs, converts to DXD format in a DSP and uses two PCM1792 converters in mono mode, one per channel.

Pairing

Within the same generation, the 312 stereo amplifier is the power amplifier, and the 331 integrated amplifier combines the circuits of the 312 and the 326 in one chassis. Vinyl users need the phono option fitted for a moving coil cartridge.

Alternatives

The Soulution 525 preamplifier is the preamplifier from the Series 5 range.