Jeff Rowland Cadence Owners manual

JEFF ROWLAND

DESIGN GROUP

Cadence

Phono Stage

Owner’s Manual

Introduction

W

elcome to the Jeff Rowland Design Group “family” and congratulations on your purchase of what is unquestionably

one of the world’s finest phono preamplifiers. þ With its combination of industrial grade active and passive devices,

precision electronic circuitry and accurately machined chassis components throughout, your Cadence Phono Stage will

offer you many years of musically satisfying enjoyment. þ Please take a few moments to read the remainder of this

Owner’s Manual. þ A thorough understanding of the operational features will allow you to gain the maximum

performance and ease of use for which this Phono Stage was designed. þ The serial number is located on the rear

panel, and is also recorded below. The Cadence serial number begins with the letter R. Please include this number with

any correspondence regarding your Cadence Phono Stage. It has been my joy to create an audio component of

enduring value which will reflect a higher ideal of musical and artistic expression. It is my hope that these qualities will

enrich your experience of ownership.

Enjoy the music!

Jeff Rowland

President

þ Jeff Rowland Design Group, Inc.

2911 North Prospect Street

Colorado Springs, CO 80907

Phone: [phone]

Fax: [phone]

Product Features

þ Balanced XLR inputs and outputs

þ XLR to RCA adapters included for unbalanced (RCA type) phono

interconnect cables.

þ Ideal matching to all moving coil phono cartridges with four (4) position

gain and load switching capability.

þ High mass, non-resonant chassis, precision machined from 6061

aluminum plate, provides maximum isolation from distortion causing
microphonics (vibration) in extremely low level circuitry.

þ Operates in conjunction with the Synergy or Coherence Preamplifiers or

with the optional Cadence AC Power Supply or BPS-1 Battery Power
Supply.

The Cadence Phono Stage is designed to be used with all low to medium

output moving coil phono cartridges. Use with high output moving coil
cartridges (output level > 1.0 mV) is not recommended. Moving magnet
cartridges cannot be used with this product.

The Cadence is unique among all phono preamplifiers offered in the market.
A specially designed phono step-up transformer, the heart of the unit,
provides the ideal interface between a moving coil phono cartridge and
carefully engineered low noise circuitry. The performance parameters
offered by this complement of electronic components far exceeds any other
phono preamplifier/equalizer offering to date.

High frequency damping, which compensates for mechanical and reactive
resonances common to all moving coil cartridges, is extremely important at
the input circuitry of all phono preamplifiers. In conventional phono

preamplifiers, damping is provided by load resistors. As a result, a significant
amount of signal energy is wasted when converted to heat within the loading
resistors. Conversely, the Cadence input transformer has been carefully
engineered to effectively damp resonant energy occurring at high frequencies
while transferring the maximum amount of useful lower frequency energy to
the active input stage. This results in significant increases in dynamic range
with no penalties of increasing noise.

Traditional step-up transformers fall short in many performance areas such as
frequency response, phase linearity (group delay), distortion, susceptibility to
external hum fields, and poor common mode noise rejection. This is largely
due to design and manufacturing limitations of the past as well as the need
for high step-up voltage ratios to meet the requirements of a high input
impedance (47K ohms) input stage. The Cadence input transformer, co­designed in conjunction with an innovative low noise input stage which, in
itself, provides a noise figure approaching that of a 50 ohm resistor, over­comes all of the aforementioned problems. A reduced step-up ratio and use
of high permeability transformer core material allow dramatic improvements
in frequency response (4 Hz to 180 KHz), phase linearity (deviation from
linear phase less than +3˚, 50 Hz to 20 KHz), and distortion (less than

0.001% at 1 KHz). Multiple layer MU-metal electro-magnetic shielding and
modern, computer controlled coil winding techniques offer a noise
immunity of 60 dB and common mode rejection ratio of 145 dB at 60 Hz.
The transformer also provides excellent rejection of radio frequency
interference (above 200 kHz), thus preventing contamination of the audio
band by RF inter-modulation products.

Following the transformer, a split active/passive RIAA equalizer, composed
of 1% tolerance parts, assures RIAA accuracy within 0.05 dB from 20 Hz to
20 KHz with distortion and noise components -110 dB below nominal
operating levels.

Introduction / Product Features