Phono boards

Looking for some advice please regarding K or S phono boards in my 82 for the Audio Technica AT-OC9XEN mc cartridge. Looking at the specifications below which board would suit it better or doesn’t it matter? I have both boards.

  • Type: Dual Moving Coil
  • Body Material: Aluminum
  • Frequency Response: 20-30,000 Hz
  • Channel Separation: 25 dB (1 kHz)
  • Vert Track: 20°, 1.8-2.2g (2g stnd)
  • Recommended Load: Min. 100 ohms
  • Impedance: 12 ohms (1kHz) (Coil/DC)
  • Coil Inductance: 25mH (1 kHz)
  • Output: 0.35mV (@1kHz, 5cm/s)
  • Channel Balance: 1.5dB (1 kHz)
  • Stylus Shape: Elliptical nude
  • Stylus Type: Nude square shank
  • Stylus Curvature: 0.3 x 0.7 mil
  • Cantilever: Aluminium pipe
  • Static: 20 x 10-6 cm/dyne
  • Dynamic: 9 x 10-6cm/dyne (100 Hz)
  • Wire Used for Coil: PCOCC
  • Terminal Pins: Brass
  • Mount: Half-inch
  • Mounting Feature: Threaded body
  • Dimensions (HWD): 17.3 × 16.8 × 25.7mm
  • Weight: 7.6 g (0.3 oz)

523 S - thats the general purpose Naim MC board. The K being a tweaked for Linn version of the S.

The gain is the same, for 523 (and 323) S & K. The E board is a similar board (to S), but with a lesser gain - to suit medium output MC’s ( E for EMT - also sometimes called R boards - for Roksan).

Studying of specifications is - IMO - not helpful… But YMMV, etc…

The S should sound better, for exactly the reason given. However, if you have both, why not let your ears decide?


The NA5xx boards that can be found and used in the NAC52 are;

NA522 - MM cartridge input x 2
NA523S - Low Output MC Cartridge input (standard) x 2
NA523K - Low Output MC Cartridge input (for higher spec carts) x 2
NA523E - Medium Output MC Cartridge input (also seen as 523R) x 2

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In theory use S, but K should be fine.

I had S in my 82 ( originally for an AT OC9) and then got a 52 that came with K. Ran that for a while until I got the 52 serviced and took that as an opportunity to get the boards swapped. As I was changing other things at the same time (moving house) I can’t comment on its specific contribution. But all combinations have sounded great!


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