Michael Fidler Spartan 15 MM Phono Amp – First Look
All Image Credit: MIchael Fidler
The new SPARTAN 15 moving magnet phonostage builds on the well-received SPARTAN 10 that first put Classic Audio Ltd. on the map. The new design features the power supply used in the PRO series for higher output with all-new parts in a total re-think of the original circuit. Precision RIAA equalization, low noise and LF X-Feed are retained for the same immersive listening experience. With a 13% price drop, compared to its predecessor, the hand made SPARTAN 15 MM phonostage offers even better value for money than before.
This latest MM phono amplifier is a complete redesign, now using the ultra-quite classic Japanese 2068 integrated amplifier creating two gain stages per channel, with each channel providing a signal-to-noise ratio of 78dB ref 5mV (220Hz-22KHz). The hyper accurate RIAA equalization of ±0.1dB is implemented using 1% tolerance film capacitors that are said to eliminate coloration. This RIAA accuracy together with a channel balance of ±0.1dB at 1kHz and a crosstalk of less than 72dB between 20Hz – 22kHz all helping to provide “great imaging”.
Similar to the SPARTAN 10, each channels gain structure is made up of two amplifiers that provide a total gain of X110 (40.8dB) at 1KHz. With the second amplifier shouldering 10.7dB (x3.43) of the channels gain, the input stage amplifier only provides one third (30.1dB or x32.07) of the channels total amplification. This ensures a sound free of “grain and harshness” creating a THD of 0.0006% from 40Hz to 22KHz.
Input overload is said to be “impossible” with its active equalization supporting a maximum input of 95mV @ 1KHz, rising to 900mV @ 20KHz. While the upgraded dual rail 17volt supplies, enable a robust output level of 10V RMS into a 10KOhm line load, simultaneously keeping “distortion-causing non-linear amplifier currents out of the ground path”.
The design also includes a fixed 22Hz, 3rd order, subsonic filter that helps prevent infrasonic intermodulation distortion by reducing over-excursion of bass units.
Rear panel signal connectivity is clean and simple using the gold-platted, unbalanced RCA connectors and a turntable ground lug.
Ensuring that noise is kept to a minimum the discrete, ±17V DC analog power supply uses an external linear transformer rather than a noisy switched mode power supply. This approach ensures that any interfering magnetic fields and electrical noise are kept well away from Spartan 15 sensitive electronics.
Front panel controls are minimal supporting; power on/off, mono/stereo mode and a fully defeatable low frequency crossfeed function that reduces vinyl vertical noise, helping to reveal bass detail on stereo discs.
Finally, the design is housed in a sleek and substantial aluminum case with a CNC milled 6mm scratch-resistant aluminum front panel with laser-etched lettering on black enclosures.
Features:
- Strict RIAA equalization to ±0.1dB for far less coloration and channel mismatch than others at ±0.5dB
- Ultra-low distortion by splitting the final gain between two optimized amplifier stages for better linearity
- Vanishingly little background noise from dead quiet input amplifiers, specially matched to MM cartridge impedances
- LF X-Feed cancels low-frequency vertical surface noise while preserving mastered stereo separation and bass response
- 23Hz 18dB/octave subsonic filter removes surface disturbances with hand-matched capacitors to preclude tolerance effects
- Mono switching greatly reduces noise and distortion on mono and heavily worn discs for better clarity and enjoyment
- Linear split power supply with start-up mute, elevated from ±15V to ±17V for even more headroom with no switching noise
Specifications:
- Gain at 1kHz, 10kΩ line load: 40.8dB, 110x
- RIAA accuracy±0.1dB: 40Hz to 22kHz
- Channel balance: ±0.1dB, at 1kHz
- Crosstalk: <72dB 20Hz to 22kHz
- SNR, ref 5mV, cartridge load: 78dB, 7900x, 220Hz to 22kHz
- Overload margin, ref 5mV, at 1kHz: 25.5dB, 19x
- Maximum input at 1kHz: 94mV RMS
- Maximum input at 10kHz: 450mV RMS
- Maximum output, 3kΩ line load: 10V RMS, 20Hz to 60kHz
- THD, 5kΩ line load: <0.0006%, 40Hz to 22kHz, 10V RMS output
- Input capacitance: 120pF
- Input impedance: 50kΩ, ±1%
- Output impedance: 100Ω
- Minimum line load impedance: 3kΩ
- Subsonic filter: 22Hz, 3rd order, -20dB at 10Hz
- Low frequency crossfeed: 145Hz, 10dB rejection at 50Hz
- Power supply: Split linear ±17V
- Power consumption: 2W at full output, 0.2W standby
- Dimensions (W*H*D): 172*60*110mm
MSRP – Black/Silver (Incl. shipping /no duties):
- US: $450.00
- UK: £330.00
- EU: €400.00
For more information visit the Michael Fidler, Classic Audio Ltd. web site.
Related posts:
