Jeff Rowland Coherence One Preamp MKII (with phono)

Jeff Rowland Coherence One Preamp MKII (with phono)


Jeff Rowland Coherence One Preamp MKII (con modulo phono) in perfette condizioni con imballo.

Very good conditions / With original box

International Buyers are welcome!
We ship all over Europe and the world. Please feel free to ask for shipping costs and other information.



Inputs  Phono + 3 unbalanced line
Main outputs (per channel) 1 inverting, 1 non-inverting
Dimensions  12.5 in. W x 19 in. D x 3.75 in. H        31.8 cm W x 48.3 cm D x 9.5 cm H
Weight  29 lbs., 13 kg
Gain  60 dB
Frequency Response  0.15 Hz to 220 kHz, -3 dB
RIAA Accuracy  20 Hz to 20 kHz ± 0.15 dB; +0, -3 dB, 200 kHz
Input Impedance  User selectable: 0-200 ohms adjustable, 47 k ohm fixed or any value.
THD and Noise  < 0.025% @ 1 kHz, 0.7 V RMS output
Max Output Level  18 V RMS
Gain  19 dB
Frequency Response  0.06 Hz to 650 kHz, -3 dB
Input Impedance  10 k ohms
Output Impedance  300 ohms (single-ended output) 600 ohms (balanced output)
THD and Noise  < 0.010% @ 1 kHz, 3 V RMS output


  • The preamplifier is designed to rest on top of its power supply so the user-friendly pair can be handled easily. Special shielding techniques allow for this configuration, and “hum field” contamination has been eliminated.
  • Lighted, feather-touch mode switches electronically control signal. The front panel switches do not alter sonic integrity, since signal switching is accomplished at the preamplifier input stage. Absolute phase reversal and full muting are other essential front panel control functions.
  • A selectable tape output section allows simultaneous recording from one source while listening to another. “Record Out: Off” position disconnects tape recorder inputs from tape out jacks, eliminating loading problems when tape recorder is not in use.
  • Volume controls are chosen for their sonic neutrality. Separate right and left trim potentiometers provide 6 dB adjustment for full rotation, permitting precise channel balance.
  • Input and output jacks are gold-plated, ground-fault protected connectors, which provide tight, corrosionfree connections. Simultaneous normal and inverting outputs allow for balanced cable operation.
  • Extremely low-noise phono sections eliminate the need for extra circuitry when using low output moving coil cartridges. The phono modules of the Coherence One Series II have been optimized for use with moving coil cartridges; for moving magnet cartridges, a module exchange can be easily accomplished by the user. Please contact Jeff Rowland Design Group from more details.
  • All main outputs are muted temporarily during initial power application, power drop or disruption. DC potential across outputs, regardless of source, will also cause a muted condition.
  • All signal amplification utilizes high-voltage, high-current, Class A field effect transistor technology.
  • All inputs and outputs are direct-coupled, thus eliminating the deleterious effects of capacitors in the signal path.
  • Precise RIAA equalization is the result of a split-passive network in the phono section.
  • Incorporation of two-stage power supply regulation: A separate outboard power supply provides tight regulation regardless of power company extremes. Additionally, this discrete component design is optimized for excellent transient behavior, thus providing very low output impedance beyond 100 kHz.
  • DC power is routed, via a power cable with a locking connector, to the main preamplifier circuit board. Compensating for power cable and circuit board inductance effects, sixteen (16) feedback-free discrete regulators adjacent to each module complete DC power distribution. This total system, in addition to separate channel balance controls, provides dual mono operation and precise regulation at each stage throughout.
  • Time-related distortion, particularly in low-level phono stages, is eliminated by a totally feedback-free design.
  • Mil-spec circuit board material, with oxygen-free copper traces and high-temperature mask provides superior electrical characteristics.
  • All signal switching is accomplished with hermetically sealed, gold- contact signal relays.
  • AC power line filter offers excellent line noise rejection.
  • All critical circuitry is encapsulated in a thermally-conductive epoxy to ensure excellent thermal stability, mechanical integrity and to facilitate ease of service



Consonance Srl

Ricordo da bambino zia Maria a casa della nonna suonare con il Petrov Pianofortissimo di Carosone, un brano da virtuosi che lei eseguiva con naturalezza. L’idea di riprodurre la musica dal vivo in un luogo protetto come la casa di mia nonna mi ha spinto a fare di questa passione il mio lavoro. A 14 anni andai per la prima volta in un negozio di dischi, chiesi i Police e ascoltai Bring On The Night in un “Pioneer A400”: fu un momento indimenticabile, un rituale di iniziazione…

Da qui è nata la mia passione: all’istituto agrario passavo ore tra i banchi di scuola ad immaginare come potesse suonare quel pezzo strappalacrime di Tracy Chapman, Baby can I hold you, con le casse di ultima generazione Yamaha. L’adolescenza l’ho passata costruendo o riparando amplificatori Marantz che trovavamo a casa di amici e parenti.A un certo punto con mio padre decidemmo di creare Consonance, per coniugare questa passione con il lavoro: e sono passati quasi 30 anni dal fatidico 21 aprile del 1991, quando aprimmo il primo negozio.

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