Classe Audio C-501 User manual

CLASSÉ AUDIO
C-501
REMOTE CONTROL
BALANCED PREAMPLIFIER
C-501
OWNER'S MANUAL

CLASSÉ DESIGN PHILOSOPHY
1. REPEATED LISTENING DESIGN SESSIONS:
Fine tuning of sound by exchanging and mixing of parts (transistors, capacitors, wiring, PCB boards
etc.), and adjusting many specific operating voltages within proper engineering ranges, producing an
overall sonic recipe giving the most natural harmonic realism of music typical of instruments in a
live performance.
2. UPGRADABLE SINGLE CIRCUIT DESIGNS:
All Classé products (all preamps and all amps) share exactly the same circuit design philosophy
(excluding moving coil and moving magnet phono circuits). This means all amplifiers and all high
level circuits of the preamps benefit from the same design goals. Similar circuits are then tailored to
different power levels etc. Differences between less expensive models and more expensive models
are parts quality and compliment, power supply extravagance and the amount of filtering etc., as
well as features and packaging.
This means that for years Classé has been constantly sonically fine tuning and technically upgrading
this circuit design and its application, thus reaching a very high level of natural musical enjoyment,
as well as excellent reliability which benefits all models - least expensive, most expensive, preamps
and amplifiers alike.
3. EXTREME LONG LIFE IN REAL WORLD CONDITIONS:
Choosing the best attainable quality parts and materials combined with the advantages of the two
above-mentioned areas provides Classé owners with years of proven trouble free reliability and
musical enjoyment.

-3-
C-501
OWNER'S MANUAL
TABLE OF CONTENTS
UNPACKING & SET-UP..................................................... 4
A.C. LINE POWER............................................................... 5
INPUTS.................................................................................. 6
OUTPUTS ............................................................................. 8
FRONT PANEL CONTROLS............................................... 9
FEATURES AND SPECIFICATIONS ................................. 18

-4-
U
NPACKING & SET-UP
Your new preamplifier has been carefully wrapped in heavy gauge plastic, packed in semi-
rigid foam and contained in a special box. To remove the unit, open and spread the top flaps of the
box. By its sides, lift out the entire unit with the foam pieces intact. Remove each foam side by
pulling straight out. Remove the plastic wrap and inspect the unit for any concealed damage. Apart
from this owner's manual, please ensure the following has also been included:
1) Detachable A.C. linecord.
2) 5/64 in. Allen key for top cover
3) Remote Control unit (Allen key and Batteries AAA X 2 included).
Please report any damage or missing parts to your dealer promptly.
This preamplifier, being capable of very high gain, must be located in a position free of any
hum-inducing magnetic fields. (This also applies to turntables and interconnect cables.) Positions
adjacent to power amplifiers, A.C. line filters, or regulation devices should be avoided. Ideally, a
few feet should separate the preamplifier from the power amplifier. As well, keep low-level
interconnect cables away from the power amp and separate from A.C. linecords.
Heat generated by the preamplifier is negligible. Air space around the unit need not be a
concern.
Check the Serial Number sticker on the back of the unit for the correct operating voltage.
Regardless of voltage, the fuse rating should be 2 AMP SLO-BLO.

-5-
A
.C. LINE POWER
The preamplifier has no power switch. Its low power consumption and improved sonics
from always being ON led to the omission of an ON/OFF switch. In fact, while thoroughly musical
shortly after turn-on, the preamplifier will exhibit "sonic growth" for the first 300 hours of used.
For optimum sonic performance, you should consider use of the optional CLASSE
REFERENCE A.C. LINECORD. Consult your dealer regarding this accessory.
SAFETY FEATURE: The preamplifier is designed with an Auto-Muting Circuit which
engages and is indicated by two FLASHING RED ARROWS when the unit is first connected, or
after an A.C. power failure. After 45 seconds of stabilizing the preamplifier is automatically
switched to "MUTE" mode, after which all operating functions such as input etc. may then be
selected.
CAUTION: "FLOATING THE GROUND” OR DEFEATING THE GROUND ON A 3-
PRONG LINECORD MAY CREATE A SHOCK HAZARD. CONNECT ALL INTERCONNECT
CABLES BETWEEN THE ELECTRONICS BEFORE CONNECTING THE A.C. LINECORDS
TO THE WALL OUTLETS. THIS WILL REDUCE THE POTENTIAL SHOCK HAZARD. SEE
ALSO THE WARRANTY SECTION OF THIS OWNER'S MANUAL.

-6-
I
NPUTS
The input jacks are clearly marked on the back of the C-501. The following inputs are
provided: BAL 1, BAL 2, REG 1 (also used for Phono), REG 2, REG 3, REG 4, TAPE, and a
SURROUND sound loop. (see figure 3).
OPTIONAL INTERNAL PHONO FEATURE:
The REG 1 input jacks are to be used with the optional phono feature (see fig.6) The phono
ground screw is located between the REG 4 and TAPE IN jacks. The optional phono can
accommodate both magnetic and moving coil cartridges of various outputs. In the MC position, gain
of the Moving Coil stage is factory preset at 16dB which matches perfectly with most typical MC
cartridges. With the resistor kit included with the optional phono feature, the gain can also be
adjusted to 20db, 25db, or 30db in order to optimize system gain, and lower noise while using other
less typical MC cartridges. (Note: The MC gain is in addition to the standard MM gain of 42dB). To
change the MC gain, proceed as follows:
1. Disconnect A.C. linecord from the wall outlet.
2. Remove top cover with Allen key supplied.
3. Locate R245 and R145 (see fig.6), which are the MC gain setting resistors for the LEFT
and RIGHT channel respectively. Remove the resistors and replace them with newly selected ones,
according to the following chart.
GAIN COLOR CODED RESISTOR (or) NUMERICAL RESISTOR
Standard: 16db (Brown, Brown, Black, Black) 1100 (110 ohms)
20db (Red, Black, Black, Black) 2000 (200 ohms)
25db (Orange, Grey, Orange, Black) 3830 (383 ohms)
30db (Violet, Blue, Grey, Black) 7680 (768 ohms)
4. Having completed the resistor changes, replace the top cover.

-7-
BALANCED, TAPE, AND REGULAR INPUTS
The BALANCED INPUTS are true differential high level inputs, wired as follows:
PIN 1: GROUND
PIN 2: POSITIVE (NON-INVERTED) SIGNAL
PIN 3: NEGATIVE (INVERTED) SIGNAL
The Balanced inputs may be used with CD players that have a balance output, or any other
high level, balanced source.
The TAPE IN of the C-501 should be connected to the LINE OUT or TAPE OUT of the tape
deck. (See FRONT PANEL CONTROLS: TAPE SWITCH.)
The Regular inputs may be used with any high level sources (REG 1 may also be used with
the optional Classé Internal Phono Feature.)

-8-
O
UTPUTS
The C-501 has both regular (single-ended) and balanced outputs. Both are working at all
times, and may be used separately, or simultaneously.
TAPE OUTPUT
Whichever input is selected will be fed to the TAPE OUTPUT jacks. This should be
connected to the TAPE IN or LINE IN of the tape deck.
REGULAR OUTPUTS
Simply connect your regular interconnects to the RCA output jacks marked REGULAR OUT
on the back of the C-501.
BALANCED OUTPUTS
A balanced power amplifier and balanced interconnects are also required. For use with
balanced power amplifiers other than Classé, the wiring of the 3-pin XLR connectors must be wired
as follows:
PIN 1: GROUND
PIN 2: POSITIVE (NON-INVERTED) SIGNAL
PIN 3: NEGATIVE (INVERTED) SIGNAL
If the pin configuration of the power amplifier differs from above, the balanced interconnects
must be modified to accommodate the different power amp.
Having confirmed the correct connections, plug the XLR connectors of the balanced
interconnects into the locking XLR connectors on the rear panel of the C-501 marked BALANCED
OUT. (To remove the connectors, press the tab above the connector.)

-9-
F
RONT PANEL CONTROLS
NOTE: All functions (except Display, Gain, and Phase) may be activated directly on the front panel,
or otherwise by the hand held remote control.
DISPLAY:
Three (3) different display brightness levels can be selected (Full/Medium/Low as well as Off).
NOTE: With display set at the OFF position, activating any switches on the front panel or from the
remote control unit will temporarily turn the display to ON at full brightness. The display will
automatically turn back to OFF after approximately 10 seconds from the last change.
GAIN:
The dual gain feature provides the user to set the preamplifier either at REGULAR gain of
18db or LOW gain of 12db. The red indicator "GAIN" appears in the display when LOW gain is
selected.
PHASE:
Phase of the output signal can be switched between inverted (180 degrees phase shift) or
normal non-inverted (0 degree phase shift). The red indicator "PHASE" is shown when the unit is in
the inverted mode.
TAPE
The TAPE button selects the input signal, between the TAPE and SOURCE inputs, which
goes to the main REGULAR and BALANCED output jacks. The red indicator "TAPE" appears
when Tape input is selected. However, the SOURCE signal always appears at the TAPE OUT jacks
and shown in the display.

-10-
SURROUND
When the surround mode is engaged, the selected signal is directed to the SURROUND
output connectors where it is sent to a Surround Sound Processor for the decoding process. The
Front-Left and Front-Right output signals from the Surround sound processor are then fed to the Left
and Right Surround input connectors on the back of the preamplifier. The main outputs of the
preamplifier (both Balanced or Regular) are now to be connected to the amplifier powering the
Front-left and Front-right speakers of your surround sound system. (see figure 4)
All preamplifier functions (except input select, display, and mute) are disabled in the
surround mode.
SAFETY FEATURE: The volume control of the preamplifier is automatically brought back to the
MIN position, and MUTE is also engaged when the preamplifier is switched back from the surround
mode to the regular stereo mode.
VOLUME CONTROL
The preamplifier volume control has a total of 60 steps of level adjustments which varies the
level of both channels simultaneously. The volume can be operated from the remote using the hand
held control unit or manually turning the control knob at the preamplifier.
The volume will turn up or down ONE step at a time when the buttons are pressed
intermittently. When the buttons are pressed and held constantly the volume will change rapidly
until the pressed volume button is released.