Classic Audio Spartan 5 Phonostage

September 2, 2022

CLASSIC AUDIO SPARTAN 5 PHONOSTAGE ANNOUNCED

The Classic Audio Spartan 5 by Michael Fidler, is a high-efficiency, all-linear moving magnet phonostage.

The Classic Audio Spartan 5 Phonostage is a single-stage phono preamplifier. with RIAA accuracy, a second-order subsonic filter, a mono switch, and a split linear power supply.

CLASSIC AUDIO SPARTAN 5 PHONOSTAGE

Made in Kent, England and utilising all through-hole technology, the Spartan 5 is intended as an upgrade over integrated phonostages. Film capacitors throughout are used to enable an ±0.25dB RIAA accuracy. There is also a subsonic filter integrated into the input coupling network. For cancelling stereo field noise and distortion on mono pressings, a mono/stereo toggle switch is included on the front panel.

MOVING MAGNET

The amplifier sits on a double-sided ground plane PCB. It was selected for very low noise with moving magnet cartridges, with an SNR of 76dB against 5mV when connected to a moving magnet cartridge. Similarly, the RIAA network is matched to the amplifier to keep distortion as low as possible, below 0.0015%. The Classic Audio Spartan 5 phonostage has an output that can drive a 5kΩ load (two 10kΩ line inputs in parallel) with 8.5V RMS. Referenced to a 5mV cartridge output, it has an overload margin of 24dB.

LINEAR SPLIT POWER SUPPLY

A linear split power supply is used, taking the power transformer and its magnetic fields out of the enclosure for better mains isolation. RC smoothing is used instead of conventional regulation for higher efficiency with the simple design. As a result, the manufacturer tells us that total power consumption is less than 0.5W so the unit can be left continuously powered.