RCM Audio Sensor II mk 2RCM Audio Sensor II mk 2
RCM Audio

Sensor 2 Mk II Phono Stage

Sensor 2 Mk II is a phono preamplifier pushes the performance of it’s predecessors even further. it has evolved from RCM’s experience and attempts to improve the parameters of a device as demanding as it gets.




Just like the first version, Sensor 2 MkII stands out from other phono preamplifiers with it’s high output level. RCM’s experience led them to the conclusion that a value of at least 1 volt is necessary to retain a high-quality sound. It’s caused by many factors, including the higher level signal preference of the input step. The best solution would be to increase that number to 2 volts – same as an average CD player. Doing that imposes some high requirements for the entire device, since, for MC cartridges with output at 0,3mV, that would require the signal to be amplified by 76dB – over 6300 times!

Sensor 2 MkII allows you to select between single-ended or balanced outputs. The signal coming from the cartridge is symmetrical, which enables an appropriate configuration of the input to widen it’s dynamics ranges while limiting the noise. Why should you fix what’s not broken?

Setting the load impedance is done via the switches on the back of the device.

Sensor 2 MkII features an 8-way switch that allows more options, which, in turn, leads to more precise setup of the amplifier. Also in the back you’ll find the switches that allow for setup of gain and output stage mode (single-ended or balanced). The amplification is handled by selected integrated circuit, and RIAA correction is performed by a two-step passive system with low-noise resistors and polypropylene capacitors. To assure precise signal correction every element of the filter system is measured and hand-picked, which results in signal fluctuations of below 0,3dB in the 20Hz to 20kHz range.

Another very important part necessary to achieve overall success is the power supply. Sensor 2 Mk II features a symmetrical power supply that is constructed to minimize signal distortion. Great care has been paid to selecting the capacitors in the filtering circuit and lowering the output impedance of the amplifier. The decision to separate the power transformer from the rest of the circuit and in it’s own chassis also affects the sound in a major way. The changes made to that part of the device include the main power supply and the operational amplifier. The first part consists of a transformer, bridge and first step of stabilization. The second step is separated and found in the preamplifier chassis.

The chassis of the amplifier and power supply are made of hollow rectangular cross-section tube that drastically reduce flexing. All elements are made from non-magnetic materials.

This extensive upgrade results in increased dynamics, lower noise floor and a larger sound stage both in width and depth. Anyone familiar with Sensor Prelude will be most impressed when they hear the improvements in Sensor 2 MkII that is delivered with only a modest increase in cost over the original. At it’s price point Sensor 2 MkII is still exceptional value for money just like before, only better now.

RCA – Balanced and Unbalanced (selectable via switch)

1 pair balanced XLR
1 pair unbalanced RCA (single ended)

Input sensivity
0.3 – 5mV (selectable in 7 steps)

52 – 76 dB (2 Vrms output at 1 kHz)
0,3 – 0,4 – 0,6 – 0,9 – 1,4 – 2,5 – 5 mV

Input impedance
20 – 47000 ohm (selectable in 8 steps)
20 -30 – 50 – 100 – 200 – 400 – 1000 – 47 000 ohm

Input capacitance
150 pF

0,01% (1kHz)

RIAA lineary
+/-0,3dB (20Hz – 20kHz)

Nominal output
2V rms

Max. output level
8V rms

Output impedance
70 ohm

0,01% (1 kHz)

85dB (lowest gain settings)

RIAA linearity
+/- 0,3dB (20Hz – 20kHz)

preamplifier 245 x 227 x 110 mm (without terminals)
power supply 122 x 230 x 70 mm (without terminals)

preamplifier 3,5 kg
power supply 1,7kg

Power consumption max
17 W

Gold Furutech RCA, XLR input and output sockets and IEC chasiss socket with Furutech fuse.
Rhodium Furutech RCA, XLR input and output sockets and IEC chasiss socket with Furutech fuse.