Accuphase C-27 Brochure
m Separate MM/MC amplifi er circuitry ensures ultra low noise m Highly precise
equalization with only ±0.3 dB RIAA deviation
three settings for MM and six settings for MC
up to 70 dB
and unbalanced analog outputs
m Three analog player inputs with separate settings memory m Balanced
m Versatile impedance switching with
m Gain switching enables high gain of
m Polarity selector for balanced outputs
The Ultimate Phono Equalizer Amp — Separate circuitry for MM and MC
ensures ultra low noise performance and outstanding RIAA precision. Versatile
load impedance selector with three settings for MM and six settings for MC
brings out the best in every cartridge. Subsonic fi lter, and high gain capability
of up to 70 dB with gain switching. Three analog player inputs with separate
settings memory for each input.
The analog phono record is experiencing a quiet boom
among discerning music lovers. It goes without saying that
a phono equalizer of high quality is essential to extract
the enormous richness of sonic information engraved
on vinyl records. Furthermore, the selection of tonearm,
cartridge and other parts of the playback system requires
a thorough understanding of audio fundamentals. This is
a fi eld where some investment of time and effort can yield
immensely satisfying results.
Accuphase has gained considerable expertise in designing
and building phono equalizers, either integrated in
preamplifi ers or available as option (AD-2810 and AD-20).
In response to the wishes of audiophiles worldwide, we
have now developed the C-27 as a high-end standalone
phono equalizer amplifier, capable of exploring the
possibilities of the analog disc to the fullest.
Because the output signal level of a record player is
extremely low, high-gain amplifi cation is required before
supplying the signal to subsequent stages. Distortion
and noise should be kept to an absolute minimum, and
excellent linearity from low to high frequencies is also a
must. In the C-27, these goals are achieved by employing
completely separate amplifi er sections for MM and MC,
each with optimized circuit topology and strictly selected
parts for no-compromise performance. S/N ratio, THD,
high-frequency characteristics, linearity and all other
parameters approach the ideal in performance. What’s
more, the C-27 is perfectly equipped to accommodate a
wide range of cartridge output voltage ratings and load
impedance requirements. To ensure optimum matching,
three different settings for MM and six different settings
for MC can be selected.
Designed to raise the bar for phono equalizer amplifi ers,
the C-27 will bring out the characteristics and musical
qualities of any phono cartridge to optimum effect,
providing pure music enjoyment from those legendary
analog discs.
C-27 Functions and Features
■
Separate MM/MC amplifi er confi guration ensures ultra low noise
■ Highly precise equalization: RIAA deviation only ±0.3 dB
■ Monaural construction with separate toroidal power transformers
and separate equalizer boards for left and right channel
■ Versatile impedance switching options
MM
1k, 47k, 100k
MC
3, 10, 30, 100, 300, 1k
Load impedance indicators Load impedance
■ Subsonic fi lter
(10 Hz, -12 dB/octave)
■ Gain switching enables high
gain of up to 70 dB
Subsonic fi lter and
gain indicators
■ Equalizer PCBs made from Tefl on* (glass fl uorocarbon resin)
with low dielectric constant and low loss
* Tefl on is a registered trademark of DuPont USA.
■ Gold-plating of all major parts in signal path
■ Three inputs for analog players or tonearms, each with a separate
memory for MM/MC, load impedance, gain, subsonic fi lter and
other settings
(LEDs show selection status)
Input selector
Filter
button
selector
Gain selector
button
MM/MC indication
Filtering capacitors
MM/MC
selector
Power transformer
LEFT
CHANNEL
LEFT
CHANNEL
INPUTS
RIGHT
CHANNEL
GND
GND
GND
MM Amplifi er Section
+
IMPEDANCE
SELECTOR
1kΩ
47kΩ
1
2
3
INPUT
SELECTOR
MM-MC
100kΩ
IMPEDANCE
SELECTOR
3Ω
10Ω
30Ω
100Ω
300Ω
1kΩ
IMPEDANCE
LOAD
MM
AM
P
–
RIAA EQUALIZER
NETWORK
DC SERVO
GAIN
MC Amplifi er Section
+
MC
AMP
–
RIAA EQUALIZER
NETWORK
DC SERVO
GAIN
GAIN
Same as LEFT CHANNEL
■ Two separate
board assemblies for
left and right channel,
using Tefl on substrate and
carrying dedicated MM and
MC amplifi ers, phono equalizer
amplifi ers, and logic relays for signal
switching to ensure shortest possible
paths between inputs and outputs.
+
–
SUBSONIC
R
FILTE
FILTER
–1
FEEDBACK
NETWORK
–1
FEEDBACK
NETWORK
BALANCE
CONNECTION
UNBALANCE
BALANCED
D
LEFT
CHANNEL
OUTPUTS
C-27 Circuit Diagram
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