Line Magnetic LM-502 CA switchable tube D/A converter

Yesterday I began asking myself “Where did all the tube DACs go?”, my renewed interest in which will be revealed in due course. Yes, I’m aware of the glass and gas inside AMR’s DP-777 but, for now at least, I’m focussing on the budget space: hitherto radar-dodging, entry level DACs with tube output stages that sell for US$3000 or less.

DAR reader Chris Jorg chimed in to bring Line Magnetic to my attention, referred to in some quarters as the ‘Shindo of China’. But it’s not quite that simple. Line Magnetic are a South Korean company whose manufacturing base sits in the Guangdong Province of China. There they make loudspeakers, amplifiers, CD players and – you guessed it – DACs. DACs with tubes output stages no less – which brings us to their LM 502-CA D/A converter…

Let’s start with its digital inputs, of which there are five: AES/EBU, BNC, USB, optical, and coaxial. Each are capable of decoding up to 32bit/192kHZ PCM. No DSD, no worries. USB comes from the everywhere-all-the-time XMOS but no word if Line Magnetic use the stock code or not.

The LM 502-CA DAC offers switchable tube (3V) and solid state (2.5V) outputs which gives it a (theoretical) leg up against the mutually exclusive Cary Audio DAC100t and DAC100.

Again, like the Cary, analogue and digital sections are power by separate transformers. A toroidal handles the former whilst an EI juices the latter. More unusually, a 6Z4 handles tube rectification before the signal sees twin 12AU7/ECC82 bottles.

Much of this is reminiscent of the original Eastern Electric Minimax which saw a single 12AU7 on its switchable tube output and ESS Sabre 9018 silicon.  Decoding on the Line Magnetic is handled by the slightly older ESS Sabre 9016 which probably accounts for its 8db dynamic range advantage over the aforementioned Cary (which decodes using the more humble ESS Sabre 9023).

Specifications

• Frequency Response: 15Hz～50kHz
• Sampling Rate: 32bit 44.1KHz 48KHz 88.2KHz 96KHz 176.4KHz 192KHz
• Digital Input Impedance: 75Ω
• Output Impedance: 2 kOhm (Tube), 600 Ohm (Solid State)
• Dynamic Range: 120dB
• Dimensions: 376mm x 345mm x 191.5mm
• THD: 0.5% (Tube), 0.02% (Solid State)
• Power Consumption: 24W

Note the absence of SNR specifics.

The Line Magnetic LM 502-CA sells for US$1800 stateside and AU$1990 down under.

Further information:  Line Magnetic (Chinese only) | McLeans Smarter Home Entertainment | Tone Imports