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Kr 15.000
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Annonse nummer: 243643
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When manufacturing units and assembly kits, B.M.C. implements unusual concepts in
order to reach a level of innovation and perfection that makes possible the kind of
transmission which truly does justice to your music.
The B.M.C. Phono MCCI is a completely balanced, passively equalized and degenerative
feedback-free moving coil phono amplifier with a current injection input and a LEF single
ended Class A output.
Amplifier circuit:
1. Balanced current injection input
2. Common base circuit as the most broadband basic circuit
3. Automatic gain adjustment
4. Degenerative feedback-free circuit with short signal path
5. Balanced circuit
6. Balanced LEF single ended Class A output
Equalization and adjustment options:
7. Passive equalization in the current-to-voltage conversion
8. Neumann constant (optional classic RIAA)
9. RIAA adjustments in deep bass and warmth range
10. Gain switchable in three steps
11. Subsonic filter switchable
High-end components and completion:
12. Special low-noise transistors with high hFE, ten each/parallel
13. “Balanced current” capacitors to ensure precision and richness of acoustic color
14. Non-inductively wound polystyrene capacitors
15. Metal film resistors in thin-film design with 0.5% tolerance
16. Gold-plated 4-layer circuit board
17. Copper-plated iron shield case covering the core module

Amplifier circuit:
“Current Injection” (CI) is a power input that makes the pick-up’s current immediately
part of the amplifier. The MC pick-up works as a generator by injecting its own current
into a system of balanced DC currents, the shift of which results in a notably higher
output voltage. CI uses the pick-up’s original current and the higher voltage corresponds
to the original quite exactly, so it is rather a current-to-voltage conversion than an
amplification. Loss of dynamics, distortion and discoloration of the signal are
considerably lower than with traditional circuits.
The current injection input circuit is an exceptional implementation of the principle of
the common base circuit. The common base circuit is the most broadband, low-
distortion, dynamic and therefore most musical of the three basic circuits, but, with a
low-impedance input and a high-impedance ouput, it also has two disadvantages.
Fortunately though, this circuit is a perfect fit for our best audiophile sources: MC
systems and D/A converters.
Some of the best MC amplifiers of the last decades employ this concept of the common
base circuit, but only when using an ungrounded, balanced input, the MC system can be
connected to such a circuit without compromising quality.
The current for the CI mode comes from the generator impedance and the impedance of
the CI input. This allows for basically automatic gain adjustment to different MC systems,
because a high-output MC system, on the one hand, provides a higher current, while, on
the other hand, the current is lowered by the higher impedance. Amplification happens in
two very short steps, and, as there is no degenerative feedback, no superfluous
amplification is needed.
Essentially there are many ways to construct voltage amplifiers pretty distortion-free,
but in the end a stable current driver is vital. When considering dynamics there are no
alternatives to single ended amplifiers. However, even those have disadvantages, such
as compulsory class A mode and higher even-numbered distortions. LEF single ended
class A prevents distortions due to the fact that the transistor driving the output does
not pass through its characteristic curve.
A completely balanced circuit keeps the supply voltage constant, because when a signal
passes through, additional consumption of one symmetric channel is compensated for by
lower consumption of the opposite hand symmetric channel. Accordingly, the supply
voltage is not modulated by the music signal. The fact, that any effect of supply voltage
variations is equiphase on both symetric channels but that in a symmetric chain only
differences are processed, constitutes another advantage.
When talking phono one hast to bear in mind that with high levels the output of a phono
amplifier produces some (few) volts, while the input has a sensitivity of uVolts. To make
things clear: if the output does not modulate the supply voltage (through a balanced
class A circuit) and, if, on the other hand, the effect of all persisiting interferences of the
supply voltage is equiphase on the inputs, that is a great accomplishment and enables
the listener to deeply delve into music!
The balanced mode therefore immensely increases the sound’s inner sereneness, which
creates space for fine details, dynamic leaps, ease of performance combined with threedimensional
spatial reproduction.

RIAA equalization and adjustment options
Since all B.M.C. analog-circuits work without degenerative feedback, “active”
equalization is of course out of the question for the RIAA equalization. Precise RIAA
correction is achieved by “quasi-passive” equalization in two uncoupled stages, that
means in a frequency-dependent current-to-voltage conversion. This concept steers
clear of required over-amplification (accompanied by high reserve of the power supply)
of frequencies that are subsequently lowered, which is a disadvantage of traditional
passive equalization. The B.M.C. Phono MCCI integrates the neutrality of passive filtering
and the avoidance of superfluous amplification.
Traditional RIAA equalization peters out with infinite attenuation towards high
frequencies, this implies that records would have to be cut with infinite amplification
towards high frequencies, which is of course impossible. Insofar, the traditional RIAA is
always wrong. The cutting machine manufacturer Neumann introduced a quasi-standard
for the limit of high frequencies decades ago. The difference the Neumann correction
makes in the level is small, but definitely distinguishable. Phase correction at the top end
of the transmission range is even more important. You may turn off the Neumann
correction and easily perceive its advantages: there is just more air and openness in the
Correction of recording deficiencies or pick-up/tone arm combinations with too little
bass can be performed by elevating the lowest deep bass as well as the warmth range.
Even though some pick-ups automatically adjust the amplification, there are still designrelated
differences in their levels. Because of that the Phono MCCI offers three
switchable levels of gain.
Ideally, tone arm and pick-up should fit each other and be sufficiently attenuated. If that
is not the case, you can activate a mild subsonic filter.
High-end components
The special transistors of the Phono MCCI have a very high hFE and a typical noise figure
of 0,3 dB, which is today’s achievable value. In the Phono MCCI ten transistors work
parallel, reducing fluctuation noise by approximately another 10 dB! Obviously, there are
virtually no solutions for MC phonos that are even more low-noise.
The balanced current electrolytic capacitors have a completely symmetric characteristic
curve for both polarities, and the tonally important ESR frequency range is far superior
to conventional electrolytic capacitors. This becomes evident soundwise through unusual
musical clarity, precision, definition and beauty, commencing in the deepest depths and
covering the whole spectrum.
Non-inductively wound polystyrene capacitors have no natural resonance, hence they
are able to create a very open, melodious high range.
SMD metal film resistors in thin-film design with 0.5% tolerance are the most high-end
parts, and their capless design makes them non-inductive.

New standards
The rise of digital technology has challenged analog technology by pressuring developers
to take their work to higher levels, which has led to new and better phono devices. This
process should not be arrested by any traditional standards. For example, unbalanced
phono inputs and layouts are not up to date anymore, because they are too interferenceprone
and therefore cannot produce the fine resolution that is demanded in order to
really enjoy music playback.
Furthermore, all aspects of a circuit are to be designed to achieve dynamic
differentiation capability across the whole frequency range, thereby allowing to take
advantage of the actual benefits of vinyl playback. Part of this is abandonment of
degenerative feedback, even in the RIAA equalization, since only a circuit which does not
loop is sufficiently quick and sensitive to detach pick-up interferences far enough from
the music so that the human brain is able to blank them out. Not until then will music be
ready to unfold in a way that is at the same time emotionally gripping and relaxing, that
takes you to different spaces or even worlds, that touches and seduces.
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