PRS Guitars Custom 50 User manual

Service Notes
Tubes
Tubes are consumables, as they have a given usable lifespan. They are part of the
heart of the tone, so keeping correctly operating tubes is essential. Tubes can fail
catastrophically or gradually, and it’s good to know what to look for if they start
to go bad. Periodically inspect them and look to see if anything inside the tube is
glowing cherry red other than the normal orange glow of the filament. This would
indicate a situation where the tube is conducting more current than it is capable
of handling and most likely about to fail. Two other conditions to observe are:
1) filaments not glowing or 2) a miniature fireworks display inside the tube. Any
of the above conditions indicate serious problems with the tube and should be
taken care of immediately. Tubes quite often are the cause of spurious noise in the
amp. Microphonic tubes will squeal or rale with the vibrations of the cabinet.
If suspected, tap each tube lightly with a pencil with the amp powered up—the
suspect tube will let you know. Note that there is a normal metallic clinking when
doing this, but a microphonic tube will be quite loud.
Replacing preamp tubes will not require any adjustment, but the power tubes will
need rebiasing to assure proper operation. After power tube replacement, initially
inspect the tubes often to assure there are no “cherry red” components within
the tube. Tubes today can have a wide variety of tolerances and a re-bias is highly
recommended with new ones.
NOTE! Capacitors may retain an electric charge and can be dangerous even when
the unit is o, unplugged, and has not been played for an extended period of
time. USE CAUTION!!!!
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“Paul Reed Smith,” “PRS,” the PRS logo, the PRS Paul Reed Smith logo, the Paul Reed Smith signature, the bird
inlays, the headstock bird, the PRS headstock shape, the PRS body shape, the PRS “scoop” design, “Singlecut”,
“Mira” and the “SE” are all registered trademarks of Paul Reed Smith Guitars “Custom 24,” “Modern Eagle,”
“SE Custom,” “SC 245,” “SC 250,” “Starla”, “Tonare”, “Sewell”, “ Blue Sierra”, and “Angelus” are all trademarks
of Paul Reed Smith Guitars. The Birds, New Birds, are copyrighted by PRS Guitars.
2 Channel Custom Guitar Amplifier
User’s Manual

Using your PRS Amplifier
IMPORTANT: Before using your amplifier, refer to the IMPORTANT SAFETY
INSTRUCTIONS insert supplied with the product.
Powering Up:
1. Make sure your speaker cabinet is connected to the correct speaker output
impedance jack with a high quality speaker cable. Do not use guitar cords.
2. Make sure the power cord is connected to the correct grounded outlet.
3. Make sure there are at least 6 inches of clearance behind the amplifier to allow for
proper cooling. Never place the amplifier against a wall or other equipment, and
keep it clear of other heat sources, such as other amplifiers or stoves. Make sure
there are no flammable items, such as curtains, behind the amp. Do not drape items
over the amps that can prevent proper cooling. Do not set drinks or other liquids on
top of the amp that can spill into the amp.
4.To increase the life of the tubes, set the “Standby” switch to the STANDBY position
before powering on. Turn the POWER switch on and let the amplifier warm up for
2 minutes before seing the standby switch to “ON”. If this is the first time you are
turning on the amp, check to see if all of the tubes are glowing.
5. Plug in the guitar cable, turn the volume knob down, and turn the standby switch
on and wait a few seconds for the bias to sele. Bring the volume up and play some
tunes.
This equipment is capable of very high sound pressure levels. Prolonged exposure
may cause hearing damage.
This equipment contains no user-serviceable parts. Refer all repairs to qualified
service personnel.
Ensure that the mains plug is easily accessible to allow the unit to be switched o.
Only connect this unit to an earthed supply socket.
THIS UNIT IS CLASS 1 CONSTRUCTION AND MUST BE EARTHED!
2 Channel Custom Amplifier Front Panel Controls
Input: ¼” Standard Mono Guitar Cable.
Lead/Clean Selector: Select your channels when not using your footswitch. When
footswitch operation is desired, select the clean channel for proper operation.
Channel Controls: Each channel is equipped with a Volume, Bright, Treble, Middle,
Bass, and Master control. Use the Volume control to adjust the level of preamp gain.
Use the Master control to adjust the overall channel volume. Adjust the tone
controls to taste.
Switchable Mid-Shift: This switch adjusts the mid-range frequency response.
Bright Switches: These switches allow you to set the overall brightness of each
channel.
Presence Control: The Presence control is global and aects both channels. Presence
aects the upper high-end. Pulling this control adds extra low-end thump.
Reverb: This knob controls the mix amount of reverb. Pull this control to disable
reverb on the lead channel only
On/Standby/O: When this switch is in STANDBY, the amplifier tubes are eectively
turned o, but are still being warmed by the filaments. Keep this switch set to
STANDBY when powering on the amplifier for at least 2 minutes to allow the tubes to
warm up. This also helps extend the life of the tubes. When set to ON, the tubes are
turned on and the amplifier can be used.
LED Indicator: Regularly check that when power is applied the mains indicator lights.
If the indicator fails, return the unit for servicing. It must not be used with a faulty
indicator.
Rear Panel Controls
Mains Socket: Always use the mains lead supplied. Your sales outlet can provide a
lead suitable for your country. Always disconnect the equipment from the mains and
ancillary units before moving.
Fuses: This amplifier is equipped with multiple accessible fuses. Replacement fuses
must be of the same type and rating as indicated. Failure to comply may result in
permanent damage to the product, and/or create a safety hazard. Always disconnect
the equipment from the mains supply before replacing a fuse.
Mains Fuses: These are located in the mains socket.
Filament Fuses/B+ Fuse: These are located on the top rear of the chassis and are
accessible via thumb-turn fuse holders.
Safety Symbols: The following symbols mean:
Warning: read instructions to understand possible hazard
Danger: electrical shock hazard
Eects Loop: This amplifier features a series eects loop that is integral to the overall
sound of the amp. Connect the Send jack with a ¼” mono instrument cable to the
input of your pedal(s). Connect your pedal(s) output to the Return jack also using a ¼”
mono instrument cable. Adjust the send and return levels via the controls.
Bias Jacks: These jacks measure the power tube current draw in mV. 1mV = 1mA. Review
the information on the back of this manual for guidance on replacing tubes. Biasing
and tube replacement should be performed only by a qualified technician.
Speaker Jacks: This is the main output for your speaker cabinet(s). Jacks are wired in
parallel. Only use a high quality speaker cable. Never use an instrument cable. Please
see “Impedance Selector” section below.
Impedance Selector: Use this switch to match the amp to the impedance of your
speaker cabinet(s). The total speaker impedance must be determined before
connecting to the amp. It is not recommended to exceed 2 total speaker cabinets. Be
sure to only use cabinets with the same impedance rating. Failure to do so can damage
the amp. The combined value of 2 matching cabinet impedances is half of the value of
one cabinet’s impedance. Examples: Two 8 ohm cabinets combine to create a 4 ohm
combined impedance. If using two 16 ohm cabinets, set the Impedance Selector to 8.
Note: Confirm the total impedance of your choice cabinets and adjust your Impedance
Selector accordingly. Failure to do so can cause arcs on the tube sockets, failure of
power tubes, or even failure of the amp.
Footswitch Jack: Connect the included footswitch to control channel switching, the
eects loop bypass function, and the solo boost feature. When using the footswitch
to control channel switching, select the clean channel on the amplifier front panel
for proper function. Only use the included footswitch. Connection of an improper
footswitch may result in damage to the amplifier.
Solo Boost: This feature is controlled by the footswitch. The boost may be individually
adjusted for each channel.