PRS Guitars 25th Anniversary User manual

25th Anniversary Amp 50 Wa 100 Wa
Power usage 250 Was 350 Was
Pre Amp Tubes 3 each ECC83
Power Tubes** 2EA EL34 4EA EL34
* *Power Tubes should be purchased as matched sets. Use only tubes in pairs or
quads that are factory-matched. Failure to use matched tubes can lead to tube
failure and amplifier damage or abnormal operation.
Main Fuses
120V 60Hz 2A 250V Type 3AG 4A 250V Type 3AG
Filament Fuses 2 each 10A 250V Type 3AG
2 each 500mA 250V Type 3AG
B+ Fuses 2 each 500mA
440V Type 3AG
2 each 1A
440V Type 3AG
Weight
Head 34 lbs (15.5kg) 40 lbs (18.2kg)
Dimensions
Head 22.5in X 11in X
9.75in
22.5in X 11in X
9.75in
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.
Instructions for Qualified Service Technician: To install the tubes, check that the power cord
is not plugged in, then remove the wooden back panel with a screwdriver and notice the
tube sockets. Note that the cooling fan may need to be unplugged from the chassis. Looking
from the back, install the Power tubes (EL34, 6L6, etc.) in the left sockets. In each case, align
the center pin guide correctly with the socket, making sure that the pin guide key fits with
the corresponding slot in the socket. The ECC83 preamp tubes can then be placed in the
smaller 9-pin sockets to the right of the power tubes. Please refer to the tube chart inside
the amplifier for proper tube locations. Be aware of the pin alignment with these, as there is
only one way they can fit. We utilize tube sockets that allow relative ease of tube installation,
but never force tubes into the sockets if there becomes a problem. Also, never torque the
tubes, only gently rock them from side to side during insertion or removal. After preamp tube
installation, place the cylindrical spring tension preamp tube covers over the tubes.
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.
Fuses
There are five fuses installed in the amplifier. Only one of these, the main input fuse, is
accessible and replaceable by the user. There are four fuses internally for added safety. Two
of these fuses are high voltage fuses and two fuses are for the lower filament voltages. In all
cases, labels indicate the type and rating of the fuse. Replacement fuses MUST BE THE SAME
TYPE AND RATING. If they are not you can permanently damage your amplifier. Please contact
your local PRS dealer or the PRS accessories web site for information on ordering replacement
fuses.
Instructions for Qualified Service Technician: Replacement of internal fuses requires removal
of the back panel and removal of the chassis. First, ensure the power cord is not plugged in,
then remove the back panel with a screwdriver. Turn the amplifier upside down and place on a
padded and safety-certified work surface. Loosen the 4 bolts holding the chassis to the top of
the cabinet. Check that all components are cool so that burns do not occur. Then, by holding
onto the transformers, lift the front of the amp so the front control is out of the cabinet and
carefully pull the chassis out.
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!!!!
Locate the fuse holders, remove them, and check for continuity. Blown fuses can indicate a
failure condition and should be treated as though a problem exists. Check the label for the
proper type and rating. After all fuses have been replaced and the amp is tested as acceptable
and safe, reinstall the chassis by working in reverse. Be sure to replace the reverb pan and
hardware, then plug the reverb cords back into place. Before installing the back panel, ensure
the cooling fan cord is plugged into the proper jack (100 wa only).
25th Anniversary Guitar Amplifier
User’s Manual
Tech Specs

Back in 2006, I was at the Dallas Vintage Guitar Show and my
band was scheduled to perform a few times. A friend said,
“Hey. You need an amp to play through, and I have a friend
who makes great amps.” He took me to the booth of a Texas
amp builder, Doug Sewell. I loved the way his amps sounded,
and after barely saying hello, Doug and I were inside rewiring
the amp I was going to play through. Since that day, Doug and I
have spent years rewiring and listening to every single possible
variation to finalize the circuits. Our goal was to have highly
usable and musical amplifiers.
I am not an amp collector. I am an amplifier user who keeps
the amps I am presently playing through. That said, after Doug
and I got several of the prototypes finalized, I sold some of
my old coveted live and studio amps because ours sounded
considerably beer. The next step was to take the prototypes
to musicians who are known for their amplifier tone as well as
their playing. What’s interesting is that when I spoke to these
artists about trying the amps, they all said the same thing.
“Sure I’ll use them, if I love them.”
In a real way, amplifiers are musical instruments. They are the
devices that “amplify” the sound of the player’s hands, the
guitar and possibly the pedal board. They must share many
qualities. They must work - they have to have a beautiful
balance of bass, midrange, and treble; the highs should be
sweet - not harsh; they should be easy to operate and be
highly musical. In addition, amps should clean up really well
when you turn your guitar down. The final quality that Doug
and I looked for are amps that sound good no maer where
the knobs are. It is a rare quality that we insisted on.
I hope this hand-crafted amplifier gives you years of
enjoyment, musical results, and pride in ownership. I
appreciate your confidence.
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 is 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 amp 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. Wait a few
seconds for the bias to sele. Bring the volume up and play some tunes.
Input: 1/4” standard guitar cord.
Treble Gain: The circuitry is configured like a vintage two-channel amplifier that has been ‘bridged’
with a Y-cord. The treble gain acts like the volume of the brighter channel. It can be used like an
additional tone knob to adjust the overall tone in a brighter or darker fashion, relative to the bass
channel gain control.
Bass Gain: As noted above, this volume controls the internal bass channel that is linked to the treble
channel. Increase this channel’s volume relative to the treble gain control to adjust the overall tone of
the amp in a brighter or darker fashion.
Treble: The treble control is very sensitive in both clean and dirty seings. Like all of the control
knobs, there are no numbers to encourage you to set the amp with your ears.
Middle: Using less mids creates crisper, more “hollow” sounding tones. Clean seings using less mids
can sound very American, working well with single coil tones for clean blues and country. Adding
mids transforms the tone to a warm, faer jazz-approved tone. Distortion with more mids can sound
very 60s and 70s, less mids ventures into 80s metal tones.
Bass: The low end control allows you to tailor the amount of bass appropriate for the speakers and
cabinet you are playing through. Inherently bassy cabinets can sound very boomy with high bass
seings on the amp. Open back cabinets generally can accept higher bass seings without this.
Presence: An additional control to adjust the overall brightness and high-end gain of the amp.
Waage: This six position switch acts as a voltage divider in the phase inverter to incrementally
reduce the drive signal going to the power tubes. The last position disconnects the switch from
the circuitry, leaving the stock values unaltered. When running the amp wide-open, it is suggested
to select the second position (one degree of aenuation) for extended tube life. Do not adjust the
waage control while playing guitar though the amp at high volumes because of potential volume
spikes between switch positions.
Jewel Power Indicator: If the lamp is lit, the amp is on. This does not indicate the standby seing of
the amp. Note: An amplifier may be plugged in and “on”, but a malfunctioning or burnt-out indicator
will not show the amp is on. Check the power cord and Power Switch if the jewel light is not on. If
these are connected correctly, then check the main fuse. If the main fuse burns out, check for proper
speaker connections. If the fuses continue to blow, the amplifier may need servicing.
Fuse: Blown fuses may indicate that the amplifier needs servicing. Use only the type and rating
specified on the back of the amplifier. See the section on Service Notes for proper fuse servicing
and replacement.
Power Switch: This cuts o all power to the amplifier. No filament current or tube voltages are
supplied.
Standby Switch: When this switch is in STANDBY, the amplifier tubes are eectively turned o, but
are still being warmed by the filaments if the POWER is on. 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. Always check this switch if the amp is ON but no sound is being heard.
Bias Jacks: Biasing and Tube Replacement should be performed only by a qualified technician.
Speaker Jacks: Get into the habit of checking these first. The jacks include a connection for 4, 8 and
16 ohm loads. There is an extension (EXT) jack with the 4 ohm and 8 ohm connection to connect
two 8 ohm loads if you wish. This scenario could most commonly be the use of an 8 ohm extension
speaker along with the internal speaker—connect each to the 4 ohm jacks since their combination
produces a 4 ohm load. Do not connect an 8 ohm load in the 8 ohm jack along with a 4 ohm or
16 ohm load in those jacks. This procedure halves the reflected impedance of each and will not
allow ideal operating conditions. If you are using more than one speaker, they must be the same
impedance. For example, use two 4-ohm speakers, or two 8-ohm speakers. Never use 2 dierent
speaker impedances - You should not mix and match. The maximum number of speakers you can
safely connect is 2. Always ensure that the speaker impedance matches the correct speaker jack
since this amp is designed to be played “wide open.” Mismatching impedances from a lower tap to
a higher speaker impedance stresses the amp more than going into a lower impedance mismatch
and can cause arcs on the tube sockets, failure of power tubes, or even failure of the output
transformer.
Confirm that the speaker cabinet you are using matches to the correct speaker jack on the back of
the amp. For the 4 OHM and 8 OHM speaker jacks, a second cabinet may be plugged into the “EXT”
(Extension) cabinet. Note: The total speaker impedance must be determined before connecting to
the speaker jacks.
25th Anniversary Amplifier Front Panel Controls
Rear Panel Controls
© 2010 PRS Guitars
All rights reserved.
“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.
Type 3AG
Replace fuse only with
same type and rating.
250V
120V~60HZ
Input Power TO AVOIDDAMAGE, NEVER OPERATE WITHOUT PROPER SPEAKER LOAD
ADJUSTMENTS ONLY TOBE MADE BY QUALIFIED TECHNICIAN
CAUTION- RISK OF ELECTRIC SHOCK - DO NOT OPEN. No user serviceable parts inside
ATTENTION-RISQUE DE CHOC ÉLECTIQUE - NE PAS OUVRIR. No pièce réparable par l'utilisateur
WARNING- TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE
AVIS - POUR RÉDUIRE LE RISQUE D'INCENDIE OU DE CHOC ÉLECTRIQUE,
NE PAS EXPOSER CET EQUIPEMENTA LA PLUIE OU L'HUMIDIT
FUSE
FUSE - 2A
250 W
BASS GAINTREBLE MIDDLE BASS
INPUT PRESENCE
TREGLE GAIN WATTAGE