SW1X DAC I SPX

The SW1X DAC I SPX is the entry point to SW1X Audio Design's NOS R2R DAC lineup, a non-oversampling, zero digital filter design built around the Philips TDA1543 chip and a 6N6P valve output stage, with a choke-filtered power supply that elevates it meaningfully above the standard DAC I. Musical, organic, and analogue in character from the first note.

Type and Technology

Non-oversampling (NOS) R2R DAC with valve output stage. TDA1543 DAC chip, one of the most musical and purist converters ever produced, directly connected to the CS8414 S/PDIF receiver with the shortest possible signal path. Class A, single-ended, anode follower, zero negative feedback RC valve amplification topology. 6N6P double triode output stage. Valve-rectified CLC choke-filtered HV power supply (6X5GT or 5Y3). Discrete transistor shunt voltage regulated low voltage supplies. Circuit wired with specially selected copper conductors. Coaxial S/PDIF input supporting up to 24-bit/96kHz (USB optional).

Sound Character

The TDA1543 has a particular warmth and musicality that delta-sigma DAC chips cannot replicate, a quality that comes from its fully resistive ladder network and the absence of oversampling or digital filtering. The SPX version's choke-filtered power supply extends this natural character, adding body and refinement that the standard DAC I's simpler supply cannot match. For listeners who find modern high-resolution DACs clinical or fatiguing, the DAC I SPX is often a revelation.

Build and Finish

Compact at 130 x 335 x 400mm and 10.3kg. Hand-assembled with SW1X's selected copper conductors of specified geometry throughout the signal path. All specifications subject to change as SW1X's ongoing research and development continues.

Best For

Digital listeners who want to experience the natural, analogue character of the TDA1543 NOS DAC topology in a well-engineered valve output stage, as an entry into the SW1X DAC ecosystem or as a standalone musical digital source.

Specifications