RedPlate RP50R User manual

RedPlate RP50R Operations Guide
1
RP50R
Operations Manual
Welcome to the RedPlate Family, thank you for your purchase of a RedPlate RP50R
amplifier. Please take a moment and review this manual for an understanding of all the
available features (or just put all the knobs at noon and play).
This Manual applies to RP50R models produced after 02/01/2014.
Signal Path Block Diagram RP50R:
FRONT PANEL:
Input Jack –Typical High impedance input to the amplifier. Designed to be “Pedal Friendly” in
the unlikely event you will ever use a pedal in front of the RP50R.
Bright Switch –Center = OFF, Down = sound of new strings, Up = normal Bright response

RedPlate RP50R Operations Guide
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TWEED PREAMP SECTION
Tweed Volume & Tone
The first 2 controls make up the Tweed Preamp section which is designed to produce the
classic Tweed tone.
Volume –This control sets the break up point and volume level of the Tweed channel.
Tone –Treble is emphasized at settings past 5, more bass at the lower numbers. When pulled
it reduces girth for the Brownface era tone. The Brownface setting can be switched back to Tweed
from the footswitch via the MID button. The tone control can be bypassed for a girth/volume jump
by pressing the Boost button on the footswitch (see the Other Features section of this manual).
BLACKFACE PREAMP SECTION
Volume Treble Middle Bass Mode
Volume –Volume level for the Blackface preamp. Pulls to enable the channel when the
footswitch is not connected (see the Other Features Section of this manual).
Treble Control - Adjusts highs (also upper midrange when the Mid Boost is engaged).
Middle Control –Controls the amount of Midrange frequencies, somewhat interactive with
the Bass Control. Pulls to enable “Deep” which scoops some midrange frequencies and
emphasizes Bass (makes your electric sound more like an acoustic).
Bass Control –Sets the amount of low end. Can be rotated to zero where it clicks off for a full
tone stack lift.
Mode Selector –A six position rotary switch, it steps through 5 progressively fatter positions of
the midrange center frequency and adds a stack lift of the Middle control for even more midrange in
position 6.
DRIVE SECTION
Gain Drive Level
The Drive section controls the amount of character to add to the preamp tone. The section’s
range of effect can be just a hint of early break up or a full on aggressive heavy metal distortion.
Gain Control –Bypasses the section when rotated to zero, this control sets the amount of
signal for the first gain stage of the section. Low settings are smoother and higher settings are
more aggressive.
Drive Control –Sets the amount of distortion by controlling the level between the 2 gain
stages of the section. Pull this control to shift into more gain and girth for the distortion (SHIFT).
Level Control –Sets the output volume of the section. Higher settings are “bigger” and more 3
dimensional. Pull this control for a reduction of extreme highs (HI CUT feature).

RedPlate RP50R Operations Guide
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MASTER SECTION
Presence Master
Presence Control –The presence circuit uses global negative feedback to remove low
frequencies which frees up bandwidth for more midrange and highs. Think of it as a tone control to
balance the relationship between highs and lows, especially when the amplifier is naturally
producing increased low end at louder volumes. The control clicks off when rotated to zero for no
presence.
Master Volume –This is an active control and actually adds gain at the higher settings. The
cleanest tones are achieved at settings below 7.
REAR PANEL SECTION
Domestic (USA):
Export:
IEC Module –contains the main power switch, power cord inlet connector and the fuse drawer
which doubles as the voltage selector on export models. To access the fuse(s) use a small flat
blade screwdriver in the notch at the bottom of the power cord inlet connector, the drawer snaps
out in a rearward direction. The RP50R can accept both the larger (3AG footprint) or smaller
European (5mm X 20mm) fuses. A time delay variety (SLO-BLO) is recommended. A fuse in the
range of 2.5 to 3 Amps is fine for domestic use (110 –125 VAC) and 1.25 to 1.5 amps is fine for
Export use (220 –240 VAC). The fuse drawer can be rotated on the export models for voltage
selection, make sure the correct value fuse is located on the same side of the fuse drawer as the
desired selection arrow. Line up the appropriate arrow on the fuse drawer with the arrow on the
bottom right of the module for the proper VAC selection.
Standby Switch –This switch allows the tubes to warm up before operating the amplifier. Wait
1 minute after power on to move it up to the operate position. For improved tube life and
performance do not leave the amplifier in Standby position for longer than 20 minutes (better to just
leave it in operate mode during performance intermissions).
FIXED/CATHODE (50 WATT / 40 WATT) Switch –This switch changes the bias architecture
of the output tubes from fixed bias (50 WATT) to cathode biased (40 WATT). The 40 WATT
position allows the use of 6V6 tubes for lower power output (~18 Watts with 6V6).
Bias adjustment and bias test point –Allows external access for bias adjustment (see bias
procedure in the Maintenance section).
Impedance Selector Ω - Set this to the total impedance of all attached speakers.
Speaker Jacks –The MAIN and EXT jacks are wired in parallel. The MAIN jack must be used
first because it has a protection device. ALWAYS HAVE A SPEAKER CONNECTED TO AVOID
PERMANENT AMPLIFIER AND OUTPUT TUBE DAMAGE.

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LINE OUT –A line level signal jack derived from the speaker output which contains the whole
tone of the amplifier.
SEND and RETURN Jacks –The send jack connects to the input of an external effects device
and the return jack connects to the output of an external effects device. The return jack interrupts
the signal path so the external effects unit must mix the wet and dry signals.
Reverb Control - Sets the amount of reverberation effect, takes the reverb out of circuit when
rotated to zero (there will be a slight volume and tone change).
Footswitch Jack - This is a standard 180 degree 5 pin DIN jack for footswitch connection. If a
replacement cable is needed, make sure all 5 wires are supported. The pinout is conveniently
located on the rear panel for use with automated switcher conversion boxes.
Fat/ Humbucker / Single coil Switch –Sets the amount of bass gain in the input of the clean
preamp stage, useful for matching the amplifier to the guitar type.
OTHER FEATURES
The RP50R comes complete with a footswitch and a footswitch cable. The cable used is a
regular MIDI cable and is readily available in any length at most music stores.
TWEED –When engaged (lit) the guitar input is routed to the Tweed channel. The footswitch
button does not work when the Blackface Channel’s volume control is pulled because it overrides
the footswitch.
DRIVE –Character Boost feature. When lit, the Drive section of the amplifier is active, not lit,
means the section is bypassed. The footswitch button does not work when the Drive section’s Gain
control is rotated to zero because it is a duplicate function.
BOOST –Girth Boost feature, it, adds volume and tone by doing a partial tone stack lift on the
Blackface channel or a full tone control lift on the Tweed channel. The footswitch button does not
work when the Blackface channel is active and the Blackface preamp’s Bass control is rotated to
zero (because it is a duplicate function).
MID –Girth Boost feature. If the Tweed channel’s tone control is pulled (Brownface mode) the
MID button is the equivalent of pushing in the control knob to the normal Tweed mode. The MID
button has no effect on the Tweed channel if the Tone control is not pulled. On the Blackface
channel the MID button increases the size of the treble capacitor for more upper midrange.

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POWER ON/OFF PROCEDURE
1. Check the Standby switch to make sure it is toggled downward for Standby operation.
2. Toggle the main power switch to the up position (this switch is located at the top of the IEC
input module). The front panel pilot light should be lit.
3. Wait one minute and then toggle the Standby switch upwards to the Operate position.
4. POWER OFF –Toggle the main power switch downward, there is no need to go into
standby first although it will not hurt anything.
MAINTENANCE SECTION
Your RP50R amp has been designed for years of trouble free operation. The vacuum tubes will
need to be replaced over time. We recommend new output tubes every 160 - 240 hours and new
preamp tubes every 320 - 480 hours.
The front and rear control panels have a protective finish that can be easily scratched with
abrasives so always use a damp soft cloth to clean them (never use paper towels). The cabinetry
can be cleaned with our super secret tolex cleaner (on a paper towel - 2 squirts of WD-40 and 4
squirts window cleaner), do not spray on the control panels.
TUBE CHART
All tube brands are acceptable; a long plate is preferred in the Phase Inverter position.
CAUTION - NEVER MIX 6L6 AND 6V6 TUBES AND ALWAYS HAVE A SPEAKER
CONNECTED.
Warning –No user serviceable parts inside so unless you know what you’re
doing please refer to a qualified service person only.

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BIAS PROCEDURE
1. When new 6L6 GC output tubes are installed it is important to re-bias the amp for optimal
performance in the FIXED (50 WATT) mode. No biasing needed for 6V6 tubes because
they can only be used in cathode bias position.
2. ALWAYS HAVE A SPEAKER CONNECTED.
3. Use a volt meter set to DC volts at lowest scale (MV). Makes sure the black lead is the
common terminal of the meter and the read lead is the DC voltage terminal of the meter.
4. Place the Amplifier in operate mode with the Master Volume and Reverb controls set to
zero.
5. Set the 50 WATT/ 40 WATT switch to the 50 WATT position.
6. Place the red meter lead in the test point hole (red tip jack) And touch (or clip) the black
meter lead on one of the metal output tube retainer clips.
7. Use a small flat blade screwdriver to adjust the bias pot for a reading of 72MV ± 5 MV (FYI
- the plate voltage is 470 volts). The reading is the sum of the idle current for both tubes.
8. Recheck the reading after 10 minutes of operation, and again after a week or two of
operation.
RedPlateAmps Warranty
At RedPlateAmps we pride ourselves making products that are built to last. The workmanship
in your RedPlate amplifier is warranted to be problem free for the lifetime of the original owner. The
actual electrical components in your amplifier are warranted for a period of 3 years. Exclusions are
vacuum tubes, reverb tanks, cables, speakers and cosmetics which are warranted for 30 days.
Improper handling or product misuse or product abuse or unauthorized repair work or unauthorized
modifications may nullify your warranty. Eligibility for coverage and covered items are at the sole
discretion of RedPlateAmps.
RedPlateAmps
www.RedPlateAmps.com
email: [email protected]
Thanks again for joining the RedPlate Family –Henry