Rothwell Simplex MM Phono Stage


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4.00 LBS
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Product Overview

The Simplex is a moving magnet phono pre-amp compatible with moving magnet and high output moving coil cartridges, giving superb performance. It uses the same class A discrete transistor circuit topology employed so successfully in the Rialto, but without the Rialto's extra moving coil gain stage. The result is truly audiophile performance in a simple, compact and affordable unit, rivaling phonostages at many times the price.


Circuit Design
An elegant discrete transistor design rather than the more common op-amp circuit is at the heart of the simplex, operating in class A and using local feedback rather than global feedback to ensure high linearity, wide bandwidth and low noise. The product of over twenty years of phonostage design experience - the first Rothwell outboard phonostage was on the market in the early 1990s - this inherently simple circuit is one which sounds detailed, spacious and musical. When the music gets busy and complex, the Simplex always reveals all the individual strands of the music and never sounds confused or harsh.

Accurate RIAA equalisation to within 0.5dB is achieved by combining multiple audiophile polypropylene capacitors. Using several capacitors where a single capacitor is more usually employed in lesser phonostages not only achieves greater accuracy but has the added benefit that the capacitors act as mutual bypasses for each other, minimising the dissipation factor and the effects of parasitic elements such as dielectric absorption.

Noise is minimised and signal integrity preserved by careful track routing on the printed circuit board, with star earthing and the use of components on both sides of the board to achieve a compact circuit with minimum loop area for low inductance. The resulting eerily quiet circuit has noise levels way below the surface noise and vinyl roar of even the best pressings, allowing the listener to enjoy recordings without the distraction of electronic circuit noise or other intrusions such as hum or buzz. Multiple stages of power supply filtering ensure that power supply noise is eliminated, and having the power supply in an external unit well away from the audio circuit prevents direct cross coupling of noise.


Cartridge Compatibilty
The Simplex can be used with all moving magnet and high output moving coil cartridges with outputs in the range 2mV - 10mV and will perform to a standard previously only expected from much more expensive units. The addition of one of our range of moving coil step-up transformers will also allow the Simplex to handle low output moving coil cartridges too, giving performance of a staggeringly high standard.






input impedance
output impedance
sensitivity for 500mV o/p
power supply
mains voltage
power consumption
packed weight


47k + 150pF
4mV @ 1kHz
>87dB (mm)
24 volts DC, center +ve
100V - 250V AC
60 x 155 x 92 mm
570g (exc. psu)





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  • 5
    A little gem

    Posted by Patrick Bloomfield on 5th May 2021

    Before purchasing the Rothwell Simplex I considered other phono stages just under the £500 price point. I eventually opted for the Rothwell due to Rothwell's openness about its design philosophy, using transistors running in Class A and basing the design purely on performance. In contrast, the other brands gave no insights into the design and one required an additional power supply unit and special cable to achieve smooth DC power bringing it towards the £1,000 price point. Anyway, the Simplex fulfils all its promises giving a fantastic performance that does not disappoint. Unlike the critics, I like its appearance and think it looks very stylish with the engraved faceplate. My first impressions were that its sound is very natural and that it brings life to the music. I noticed more details being revealed on further listening than before, such as a guitarist's fingers moving over the strings and separations of instruments. The shimmering of cymbals had more clarity than I ever heard before. Also, the bass goes much deeper than before, which sounds rich with fast attack, texture followed by decay. My only criticism is the cheap cable used from the PSU from the Walmart plug. However, I ran a simple test at full volume with the inputs blanked off and there was absolutely no audible increase in the noise floor. Therefore, no RFI or EMI is entering through the cable, so it has no detrimental effect on the phono stage's performance. The Simplex runs extremely quiet. For reference, my system comprises; Project RPM 9.2 turntable, Goldring 2300 cartridge, Tilsbury passive preamplifier, John Howes Acoustics modified Quad II monoblocks, Tannoy Berkeley 15" Dual Concentric speakers.