What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

Jeff Rowland Coherence One Preamplifier

 Rowland Research is pleaesd to introduce a preamplifier which combines technical innovation with unmatched beauty and ergonomics. Advances in field effect transistor technology and research into low-level signal recognition and resolution have positioned the Coherence One preamplifier as a standard by which other units will be compared.
The Coherence One is powered by a companion power supply which eliminates the possibility of hum field contamination  in the low level circuitry. In addition, extra care was spent on overall power supply design due to the understanding that an audio amplifier is simply a modulated power supply.
No negative feedback in all circuit location
Direct coupled design from input to output
Accepts both moving coil or moving magnet cartridge inputs
Optional strain-gauge cartridge inputs available
Passive RIAA Equalization
All signal switching accomplished with mil, spec, hermetically sealed, gold contact relays.
Continuously adjustable loading for moving coil cartridges
All FET in voltage amplification stages
Precision stepped attenuator for volume control
Muted outputs during power outages.
 An amplification system must recognize and respond to all information presented to it. The composite of this information, with all its subtleties and nuances, can be defined as Musical Truth. Once recognized, this truth must be absolutely maintained during the amplification process.
Recognition of Musical Truth has been a shortcoming of most, if not all, amplification systems. While few designers recognize and rigorously pursue the ideal, even fewer approach the realization. Amplifying incompleteness will always be unsatisfying to the music lover.
Maintenance of Musical Truth during the amplification process has often led to novel and ingenious design methods that produce spectacular specifications yet miss the ideal altogether. Although technical measurements have their place, the experienced ear must be the final arbiter of Musical truth
 Rowland Research has made a commitment to the ideal. This dedication is combined with an intimate knowledge of electronic principles and components and a thorough understanding of past and present techniques and accomplishments.
Phono Section
RIAA Deviation:  20 Hz - 20 kHz ±0,15 dB
Input Impedance:  0 to 100 Ω, user adj. 47 k Ω for MM
Equiv. Input Noise:  less that 1 nanovolt per square root Hz
Gain:  40 dB MM at 1 kHz, 60 dB MC at 1 kHz
Line Section
Frequency Response:  0,2 Hz to 500 kHz -3 dB
Input Impedance:  10 k Ω
Output Impedance:  100 Ω
Gain:  20 dB
Distortion:  less that 0,05% THD or IM below rated output
Signal-to-Noise ratio:  greater than 92 dB A reffered to rated output
Rated Output:  5 volts RMS
Power Supply
Transformer:  30 VA encapsulated torodial
Capacity:  10,000 microfarads total
Voltage:  ±48 volts DC
Output Noise:  less than 100 microvolts
Dimensions (W x H x D):  483 x 318 x 95 mm (19" x 12,5" x 3,75")

Weight:  13 kg (29 lbs)

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