THE THIRD GENERATION.
The Reference Phono Stage GRUENSCH MCS II SE is the result of the search for an ideal: The ultimate phonostage.
The new GRUENSCH J-FET CURRENT AMP technology is characterized by "transparency" that has been unachieved so far, which doesn't add anything to the sensitive, emotionally thrilling music signal, and doesn't leave anything out. In connection with the GRUENSCH CONSTANT CURRENT power supply technology, even the high demands of pampered music lovers are exceeded.
With the third generation of our phonostages soundquality could be further increased by a wide range of improvements and very laborious selection of components.
Furthermore features were extended with the addition of balanced outputs of the highest quality embodying a zero feedback Pure-FET-Pure-Class-A design.
When the balanced outputs are used gain can be set up to 81 dB. Thus even lowest output cartridges can be operated without the use of sound degrading MC transformers. In this way their potential of sound quality that has remained hidden can be exploited to the full.
Remarkable musicality, playful lightness and high resolution warmth – the GRUENSCH MCS II SE reference phono stage creates glimpses into music that have so far been hidden from you.
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THE AUDIO CIRCUIT - GRUENSCH J-FET CURRENT AMP
With the development of the GRUENSCH MCS II SE reference phono stage, it was possible to realize an audio circuit with "transparency" that was unachieved so far. It makes it possible for the first time to enjoy the entire wealth of colors, the fine resolution and micro-rhythmics of the analog cartridge signal.
The input resistance for impedance matching of the cartridge signal is switched contact-free due to the very small signal voltages and currents.
The subsequent audio circuit is constructed discretely with the best components throughout. It only has two amplifying stages which operate in the ideal single-ended pure class A mode with no negative voltage feedback (No NFB) applied in the entire signal path.
These innovative GRUENSCH J-FET CURRENT AMPs are the heart of the audio circuit. They work as J-FET current amplification stages like a tube triode and have almost ideal characteristics, which are described in more detail in the next chapter.
The high-precision RIAA equalization is done purely passively with the best components, like high-precision non-magnetic metal film resistors and select tin foil capacitors.
The Phono Stage GRUENSCH MCS II SE features an unbalanced and a balanced output of the highest quality embodying a zero feedback Pure-FET-Pure-Class-A design.
When the balanced outputs are used gain can be set up to 81 dB. Thus even lowest output cartridges can be operated without the use of sound degrading MC transformers. In this way their potential of sound quality that has remained hidden can be exploited to the full.
TECHNICAL AND SOUND CHARACTERISTICS
The Reference Phono Stage GRUENSCH MCS II SE with new GRUENSCH J-FET CURRENT AMP offers extraordinary technical properties resulting in excellent natural and musical sound.
The Phono Stage features consistent, ideal characteristics across the entire frequency range.
Thus distortion exhibits the same perfect musical characteristics at any measured frequency: only one minimal component, the 1st harmonic K2, can be seen – higher frequency distortion components are not present. While rapidly increasing high frequency distortion is not unusual with other designs, the minimal distortion of the Reference Phono Stage MCS II SE remains constant across the frequency and maintains exactly the same musical characteristics. Moreover, with the negative feedback-free single-ended pure class A operation of the audio circuit no dynamic distortion occurs as a matter of principle, and no distortion occurs from transistor switching.
The result is unprecedented silkiness in clarity, fine resolution, and smoothness in sound. The natural playback of the finest dynamic nuances and shading as well as explosive dynamic jumps makes music playback the ultimate experience – live, authentic, and immediate.
The fullness of previously concealed spatial information in connection with the extraordinarily high stereo channel separation also makes remarkably realistic imaging possible.
With the extremely high signal-to-noise-ratio (-76 dB), these sound properties emerge even more clearly from an especially black background.
The signal processing by Phono Stage MCS II SE is done quite deliberately unbalanced in the tonally superior single-ended mode. Thus the Phono Stage MCS II SE demonstrates extremely low distortion (0.004 %) with perfectly musical characteristics: only an extremely low K2 distortion component is present.
When looking at the frequency response, the extreme precision of the passive RIAA equalization (+/-0.1 dB in the range from 20 Hz to 20 kHz) and the enormous frequency bandwidth of the Phono Stage stand out (the frequency response only drops by 0.5 dB at 100 kHz).
The audio circuit distinguishes itself with enormous stability that has no sensitivity whatsoever to capacity load. In connection with the low output impedance and the high current capability, this allows the use of long NF cable and guarantees superior operation even when connected to preamplifiers with low input impedance.
REFERENCE POWER SUPPLY GRUENSCH CPS II
GRUENSCH CPS II, the no compromise analog power supply is located in a separate and extremely solid housing. Its internal, strict channel separation in dual mono prevents crosstalk between the channels.
Designed as the ultimate analog power supply, it features the new GRUENSCH CONSTANT CURRENT technology that is superior to even the most sophisticated battery solutions.
It supplies the Phono Stage with regulated, constant and high-purity direct current. In contrast to conventional power supply units that work with a DC voltage output, with the CONSTANT CURRENT technology there are no alternating current or alternating current interfering signals in the attached Phono Stage that could negatively influence the sensitive electronics. In addition, the supply cable between the power supply and the Phono Stage is completely immune to interference from electrosmog and is also designed to send no stray radiation of any type.
Since the supply cable between the power supply unit and phono stage only carries constant current, you can on principle choose its length as you like.
The power supply unit is switched on and off by the button set in the top plate of the phono stage. As a result, it can ideally be set up directly at the record player, and the power supply unit can be as far away as you like.
ELECTRICAL CONSTRUCTION
The phono stage features consequent dual mono design with star grounding. This effectively prevents influencing and crosstalk between the channels.
The optimized circuit layout guarantees the shortest, lowest loss signal path possible. 
The input resistors are switched completely lossless without contact on account of the minimal signal voltage or current that prevails here. Top quality reed relays regulate gain adjustment. Special selected and non-magnetic precision metal film resistors are used. The other components, such as the cast ultra-silent 90VA toroidal transformers, 105°C long life electrolytic capacitors or special axial tin foil capacitors are likewise exclusively of the very best quality.
The electrical design naturally complies with the strict VDE and CE regulations; the dimensioning of all components occurred according to military guidelines, which guarantees maximum longevity and reliability.
Each product undergoes a complete set of test measurements and is subjected to a continous operation test before being finally released for delivery after a final listening test.
MECHANICAL DESIGN - GRUENSCH SOLID CASE
The mechanical design of the case is the result of maximum demands on solidity, function and design.
Both cases are made of up to 20 mm CNC-milled pure aluminum. The extremely solid, resonance-optimized design protects the electronics effectively against microphonic influences. Moreover, special isolation feet decouple the device from the surface below it.
Apart from the shielding against high frequency radiation exposure by the solid aluminum components, the electronics of the phono stage are in addition shielded by copper- and nickel-plated steel sheeting. In this way the case of the phono stage provides the electronics with an ideal working environment – perfectly protected against stray pick-ups from the low to high frequency range and virtually free of microphonics and resonances.
The exterior design of the devices is characterized by timeless beauty and elegance. All of the aluminum components are polished, pickled and given a silver hard anodic coating. Solid aluminum controls and generous milling out also make operation a sensual experience. In addition, all functions can be conveniently set and read via the controls embedded in the solid aluminum top plate.
FEATURES
- In its third generation - MCS II SE - features were extended with the addition of balanced outputs of the highest quality embodying a zero feedback Pure-FET-Pure-Class-A design.
- The reference phono stage GRUENSCH MCS II SE has an unbalanced (RCA-type socket) input for moving coil cartridges, an
(RCA-type sockets) output and a balanced (XLR-type sockets) output.
All of the functions of the phono stage can also be switched via the controls embedded in the top plate:
Switching the phono stage and power supply unit on and off via the button embedded in the top plate of the phono stage- Adjusting the input impedance (load) to 14 levels via the solid aluminum rotary switch
- Standard setting 80 Ohm- 1000 Ohm, other value range available on customer request
- Adjustment of amplification (gain) to 14 levels via solid aluminum rotary switch
- Standard adjustment 54 dB to 76 dB unbalanced and 60 dB to 81 dB balanced, other amplification ranges available on customer request
- RIAA equalization with fifth time constant (according to Neumann) possible on customer request
- Selectable subsonic filters:
- 1) IEC (fourth time constant): lowering deep bass range –9 dB at 10 Hz
- 2) Low: lowering deep bass range -3 dB at 10 Hz
- 3) off
- Mono switch (SUM) for playing mono records
TECHNICAL SPECIFICATIONS - GRUENSCH MCS II SE Typical values
Click here or directly on the diagrams to enlarge.
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