• R50  Reference MM/MC Phono Preamplifier

    R50 is a high grade  phono preamplifier developed and handcrafted elaborately to   re-render full music spirit and connotation,whose design reference benchmark is state of the art counterpart the top  hi-end phono preamplifiers performance, tone, function, construction and fabrication.

    True balanced cartridge interface

    Two input pairs are provided for use with balanced (2 pr. XLR) or single-ended (2 pr. RCA) sources. The term "balanced" describes a system in which the audio signal is transferred via two shielded symmetrical conductors, neither of which is connected to ground. When the input port is selected as the XLR, the R50 present true balanced interface, or present as single end interface when switched to RCA.
    when the extremely-low signal levels of cartridges input to R50 by with XLR port, it becomes clear that the interference signals such as hum, RF, noise etc will not be carried by the shield(ground paths) or in some way is exposing the signal to the ground carrier.
    The true balanced signal interface to the preamplifier is a huge improvement over presently available designs. A performance balanced system was always faced with a number of technical problems. In the R50 these limitations have been overcome entirely.
    Two inputs (XLR 3pol. Female or RCA), can be configured both as MM or MC versions by the (MC or MM) cartridge load card. Thus, it supports the connection of record player with two different cartridges or the connection of two record players, each having a different cartridge (MM/MC).

    Subsonic filter     

         In order to achieve best sound results even for old or wavy records,

    R50 employs a Linear-Phase subsonic filter which attenuates the sub-audio frequencies whilst having no effect on the audible signal.

    Select able input resistance/input capacitance

    The input resistance of the MC version can be adjusted via the DIP switch on the MC cartridge load card. Thus, impedance can be adjusted to matching any cartridge. This certainly also applies to the adjustability of the input capacity in the MM versioninput resistance fixed at 47 Kω)via the DIP switch on the MM cartridge load card. The input sensitivity will be selected automatically by theMC or MMcartridge load card.


    Select able gain

    The gain of the R50 can be adjusted as Low, Middle and High by the Gain switch in 6dB step. This switch is used to more closely match your preferred volume setting on your line preamplifier. When using modern very low output cartridges, it is recommended to try setting this switch to High GAIN. Or you might try the Low GAIN position to ensure you are not overloading the input of your line preamplifier.

    Dual mono design

    As might be expected, the R50 uses a dual mono design that isolates each channel from the other. We use separate power supplies for the two audio channels in R50. In fact, there is an aluminum wall between the two channels in the R50 phono preamplifier, separating Left from Right channels physically as well as electrically.


    Regardless of the technology used, numerous details must be executed to fully realize the potential of a Dussun design. The quality of individual components, the care and craftsmanship with which they are assembled and the exhaustive inspection and testing we employ help raise the value of Dussun products. The R50 is built to the same high construction standards as all other Dussun products.

    In addition to yielding the best performance, careful attention to details is the secret of achieving both reliability and longevity.



    two pairs balanced on XLR

    two pairs single-ended on RCA

    (both select able for MC and MM)


    1 balanced1 single end

    Input Impedance For MC:


    Input Capacitance For MM:


    Gain (select able) :



    Input Sensitivity:

    (at rated output:1 kHz, -10Dbv)



    Input Overland Margin:

    MM180mV    MC7.5mV

    Output Impedance: 100Ω Balanced 50Ω single end

    Hum and Noise:

    Equivalent input noise


    51nV (-143.6dBu) A-wtd,

    189nV (-132.2dBu) Flat20 Hz to 20 kHz

    Signal to Noise Ratio:

    Ref. 2Vout

    MM(Gain M):104dB A-wtd

    MC(Gain M):88dB A-wtd

    RIAA Accuracy: 20-20,000 Hz ±0.5 dB
    Maximum Output Level: 6 Vrms
    Crosstalk,L to R or R to L: -100 dB or better 20 Hz to 20kHz
    THD: less than 0.01% at 6Vout
    Input stage CMRR:     86dB20 Hz to 20 kHz
    Subsonic Filter:

    –12 dB/octave

    10 Hz Linear-Phase Filter



    440(W)×84(H)×290(D) mm


    Shipping Weight:

    19 kg(41.9 lbs)



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