Origin Effects RD COMPACT HOT ROD User manual

OWNER’S MANUAL
Version 1.0

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Origin Effects RD COMPACT HOT ROD
www.origineffects.com
ORIGIN EFFECTS®is a registered trademark of Origin Effects Limited.
All other product names and trademarks are the property of
their respective owners and are hereby acknowledged.
MARSHALL® is a registered trademark of Marshall Amplication PLC.
Origin Effects has no afliation with Marshall Amplication PLC.
FENDER®is a registered trademark of Fender Musical Instruments Corporation.
PRINCETON®is a registered trademark of Fender Musical Instruments Corporation.
Origin Effects has no afliation with Fender Musical Instruments Corporation.
VOX® is a registered trademark of Vox Amplication Limited.
Origin Effects has no afliation with Vox Amplication Limited.
MESA/BOOGIE®is a registered trademark of Mesa/Boogie Limited.
Origin Effects has no afliation with Mesa/Boogie Limited.
TRAINWRECK®is a registered trademark of Scott Alan Fischer.
Origin Effects has no afliation with Scott Alan Fischer.
No part of this publication may be reproduced in any form or by any means, whether
mechanical or electronic, without the written permission of Origin Effects Limited.
Origin Effects Limited reserves the right to change the features and specications described
herein without notice or obligation. Origin Effects Limited cannot be held responsible for any
loss or damage arising directly or indirectly from any error or omission in this manual.
PLEASE READ ALL INSTRUCTIONS, PAY SPECIAL ATTENTION TO SAFETY WARNINGS.
Document version 1.0
© Origin Effects Limited 2021
IMPORTANT:
This product is designed to be powered from a 9VDC, >100mA
power supply with 2.1mm centre-negative barrel connector.

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Contents
Introducing the RD COMPACT HOT ROD ................................................................................................. 4
Key features ............................................................................................................................................... 4
About the RD COMPACT HOT ROD.......................................................................................................... 5
Connecting the RD COMPACT HOT ROD ................................................................................................. 6
Main controls .............................................................................................................................................. 6
POST-DRIVE EQ controls.......................................................................................................................... 8
Example settings ...................................................................................................................................... 10
Appendix A: Physical specication ............................................................................................................11
Appendix B: Performance specication.....................................................................................................11
Appendix C: Connector pin outs................................................................................................................11
Appendix D: Safety notices ...................................................................................................................... 12
Origin Effects RD COMPACT HOT ROD

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www.origineffects.comOrigin Effects RD COMPACT HOT ROD
Introducing the RD COMPACT HOT ROD
With the ability to directly shape key amp
properties like preamp voicing, break-up
characteristics and low-frequency distortion, plus a
built-in Blend control to mix in your dry signal, the
RD Compact Hot Rod allows you to quickly dial
in a range of legendary “hot-rodded” amp tones
or mix and match different avours to create your
own unique sound.
Key features
• Class-A preamp stage with realistic, “hot-
rodded” amp gain-staging
• Phase inverter and push-pull output stages
• Variable negative feedback in the output stage
• Specially designed power supply, emulating
rectier and mains transformer sag
• Reactive load to simulate interaction between
amp and speaker
• Wide gain range, from clean to full-on saturation
• Full control of tone, dynamic response and
distortion characteristics
• Blend knob to mix in your dry signal
• Powerful tone-shaping Post-Drive EQ
• High-current, low-noise electronics
• Ultra-high input impedance
• Silent switching
• High-quality buffered bypass
• Advanced power supply ltering and protection
• Premium components throughout
• Designed and built in England
The RD Compact Hot Rod is a super-charged
version of our celebrated RevivalDRIVE Compact
pedal, paying homage to the heavily modied
amps that came to dene the sound of Hard Rock
and Heavy Metal. Using all-analogue components
and replacing the valves with discrete transistor-
based circuitry, we have reproduced the sound,
response and circuit behaviour of these “hot rods”,
delivering aggressive high gain and massive
sustain.
Streamlined, intuitive controls give you full
command of both sound and feel, while the
powerful Post-Drive EQ lets you adjust the RD
Compact Hot Rod to suit your preferred amp and
settings - not the other way around.

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ABOUT THE RD COMPACT HOT ROD
Like many guitarists, our favourite tones of all time come from plugging straight into a vintage, non-
master-volume valve amp, turned up loud. When we designed the original RevivalDRIVE Compact,
we recreated every stage of a valve amp’s signal path using all-analogue components, allowing us to
capture the sound and circuit behaviour of a wide spectrum of classic amps.
Just like the legendary amp techs of the ‘70s and ‘80s, the RD Compact Hot Rod takes this platform and
pushes it to the extreme – more gain, more sustain and more aggression. We didn’t compromise when
we “hot-rodded” our pedal’s circuitry, so it has all the tone, dynamics and feel of those searing, chugging,
re-breathing amps from Hard Rock’s golden age.
While most overdrives tend to work well with one style of amp and less well with others, we want our
pedals to sound great into lots of different amps, so we designed an ingenious Post-Drive EQ lter that,
together with a three-way mode switch, makes the process of adjusting the pedal to suit your amp much
more intuitive.
The RD Compact Hot Rod features our push-pull output stage as well as a specially designed rectier
circuit, while the Highs control gives an endlessly variable set of preamp characteristics from British to
American, subdued to unhinged. Also included is a Blend control, which simultaneously backs off the
gain as you mix in your clean tone, ensuring pleasing, musical results throughout the control’s travel.

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Connecting the RD COMPACT HOT ROD
INSTR: Connect to your guitar, bass or other instrument.
AMP: Connect to your amp, power amp, mixer or recording interface. If you’re playing through
something other than a guitar speaker (e.g. PA speakers, studio monitors, headphones or direct
recording), we strongly recommend using a speaker simulator after the RD Compact Hot Rod.
9VDC: Connect a 9VDC 2.1mm centre-negative mains power adaptor (minimum 100mA).
Main controls
OUTPUT: The output control sets the pedal’s overall output level. As it isn’t part of the RD Compact Hot
Rod’s emulated amp circuitry, the OUTPUT control won’t alter the pedal’s overdrive character. It simply
lets you make it louder or quieter.
GAIN: The GAIN control functions exactly like the volume knob on a non-master-volume valve amp.
Turn it clockwise for more gain, sustain, drive and distortion. Turn counterclockwise to clean things up.
BLEND: This control lets you adjust the mix between the dry input signal (DRY) and the overdriven
signal created by the RD Compact Hot Rod. As mixing clean and very heavily overdriven signals tends to
produce undesirable results, we’ve designed the BLEND knob to gently back off the gain as you mix in
more dry signal.
Set the control fully clockwise (100% O.D.) then turn it counterclockwise to progressively mix your
original clean signal back in, delivering a rounder, fuller and more natural tone.
HIGHS: The HIGHS knob progressively increases mids and highs as you turn it clockwise, delivering a
brighter, more incisive tone while keeping the low end tight and controlled so that high-gain settings don’t
turn to mush.
The HIGHS knob provides a continuous range of useful preamp voicings, ranging from a Marshall®-style
amp with its tone controls centred (HIGHS set fully counterclockwise), to a late ‘70s Master Volume
Marshall®(HIGHS at 12 o’clock) to a cranked modded Fender®amp (fully clockwise).

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Main controls (continued)
LOWS: The LOWS control allows you to adjust the amount of bass pushing the drive circuitry. Increasing
the amount of low end (turning clockwise) results in a thick and raspy distorted sound. Conversely,
pulling the lows out of the drive path (turning counter-clockwise) will reduce the amount of low-frequency
distortion, resulting in a tighter, more dened overdrive.
Fully clockwise, the LOWS control imitates the response of a Marshall®JTM45 with the bass turned up
(but with more gain than was available from this amp).
Fully counterclockwise, it replicates the tight lows of a modded Marshall®Super Lead or a higher gain
Vox®-type circuit, such as a Trainwreck®Liverpool. In between these two extremes, the LOWS knob
produces low-end characteristics similar to a Fender®-style amp.
MORE/PRES: This control combines two parameters, both related to the effects of negative feedback in
the output stage.
Turned clockwise from the centre position (PRES), this control releases the higher frequencies from
the effects of negative feedback, progressively boosting highs just like the classic “Presence” knob on
vintage Marshall®and Fender®amps.
Turned counterclockwise from the centre position (MORE), this control progressively reduces negative
feedback in the pedal’s push-pull output stage, increasing gain at all frequencies and also varying
playing feel by modifying the break-up characteristics.
With the control centred at 12 o’clock, there is a denite threshold to this transition, with an abrupt switch
from clean to overdriven once you pick hard enough. Turned fully counterclockwise, there’s a smooth,
gradual transition from clean to fully overdriven with an earlier onset of distortion.
At 12 o’clock, the response is akin to a Marshall® with the “Presence” knob at zero. Fully
counterclockwise, the pedal behaves more like a Vox®, with no negative feedback whatsoever.

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POST-DRIVE EQ controls
The POST-DRIVE EQ ensures compatibility with a wide range of ampliers. Instead of altering your amp
or its tone controls to suit the RD Compact Hot Rod, set your amp for the desired clean sound then use
the EQ controls to adjust the pedal’s output accordingly (see tables on opposite page).
POST-DRIVE EQ switch: This switch offers a choice of three different output lters.
• P/AMP: Use this setting when plugging into a at-response power amp, FX return, mixer or recording
interface. Selecting the P/AMP setting disengages the ADJ variable lter control (see below).
• EQ1: Designed to suit the response of a Blackface Fender®-style amp, EQ1 applies a low-pass lter to
roll off excessive highs. Use this setting when plugging into a bright-voiced guitar amp.
• EQ2: Voiced for connecting to a Marshall®-style amp, EQ2 applies a high shelf cut to gently rein in
high frequencies. Use this setting when plugging into a fuller-sounding, mid-rich amp.
ADJ: When EQ1 or EQ2 is selected, the ADJ knob lets you ne-tune the pedal’s output to suit
the individual response of your amp and the way its controls are set. As you turn the ADJ knob
counterclockwise, this proprietary lter design gradually rolls off bass and adjusts the high shelf
response. The end result is a very powerful and intuitive control.
If your amp sounds too bright or thin with the RD Compact Hot Rod engaged, turn the ADJ control
clockwise. If it sounds too dark and woolly, turn the ADJ control counterclockwise.

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Step 1: Set POST-DRIVE EQ switch for the connected amp or device
POST-DRIVE EQ controls (continued)
Use the tables below to help you set up the RD COMPACT HOT ROD for the rst time with a new guitar
amplier or at-response device. Working through Steps 1 and 2 allows you to “set-and-forget” the
POST-DRIVE EQ controls and move on to having fun dialling in your ideal tone with the main controls.
AMPLIFIER OR CONNECTED DEVICE POST-DRIVE EQ SWITCH POSITION
Power amp/FX return & guitar speaker
Mixing desk & cabinet simulation
Recording interface & cabinet simulation
P/AMP
Bright, mid-scooped guitar amplier EQ1
Dark or Mid-rich guitar amplier EQ2
*Please note: the ADJ control is not active when the POST-DRIVE EQ switch is in the P/AMP position.
Step 2: Fine-tune the POST-DRIVE EQ with the ADJ control*
HOW IS THE RD COMPACT HOT ROD TONE? TURN THE ADJ CONTROL...
Too bright or thin Clockwise
Too dark or woolly Counterclockwise
Just right! Leave in this position and enjoy using the pedal!

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Example settings
THRASH PLEXI
The early years of Thrash Metal featured some
huge, Hot-Rodded tones from both sides of the
Atlantic. Cranking the GAIN, boosting the HIGHS
and PRES whilst cutting LOWS unleashes a
super-tight, super-bright Metal Plexi tone. Unruly
and aggressive yet controlled and articulate.
LIVERPOOL HOT ROD
Like an AC30 on steroids! We’ve voiced this set-
ting after the well-respected Trainwreck®Liverpool
amps which pushed the British EL84 design to the
limit. These settings provide a glassy lead tone with
ultra-sensitive dynamics. Dialling the BLEND back
to 2 o’clock mixes chime and grit with the natural
tone of your amp.
BROWN SOUND
A Modded Plexi with everything on 10! Dialling
back the MORE/PRES control mimics the reduced
negative feedback in this revered tone.
With a gentle transition into distortion and a softer
dynamic response, this classic tone could be mis-
taken for a vintage Marshall®on a variac.
CALIFORNIA HOT ROD
Inspired by the lead tones of Santana’s mod-
ded Fender® Princeton®, these settings deliver a
controlled, mid focused overdrive sound. In the
late 60s, Randall Smith was hot rodding Fender®
Princeton®combos for more gain and sustain. This
venture later turned into MESA/Boogie®.

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Measurement Unboxed Boxed
Weight 620g (21.8oz) 700g (24.6oz)
Length 143mm (5.62”) 170mm (6.6”)
Depth 66mm (2.6”) 100mm (3.9”)
Height 65mm (2.56”) 75mm (2.9”)
Origin Effects RD COMPACT HOT ROD
Appendix A: Physical specication
Measurement Value
Input impedance 1MΩ
Output impedance 1kΩ
Current draw 100mA
Power supply requirements 9VDC 2.1mm centre negative connector
Pin Description
Tip Signal
Sleeve Ground
Appendix B: Performance specication
Appendix C: Connector pin outs
Instrument & Amplier 1/4” TS sockets:

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Appendix D: Safety notices
General safety
Keep these instructions and heed all warnings. Do not use this apparatus near water. Clean only with
a dry cloth. Do not install near any heat sources such as radiators, heat registers, stoves or other
apparatus (including ampliers) that produce heat. Refer all servicing to qualied service personnel. No
user serviceable parts inside.
When using an external power supply, use only attachments/accessories specied by Origin Effects.
Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles,
and the point where they exit from the apparatus. Do not defeat the safety purpose of the polarised or
grounding-type plug. A polarised plug has two blades with one wider than the other. A grounding type
plug has two blades and a third grounding prong. The wide blade or the third prong are provided for
your safety. If the provided plug does not t into your outlet, consult an electrician for replacement of the
obsolete outlet. Unplug this apparatus during lightning storms or when unused for long periods of time.
FCC certication
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant
to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the instructions, may cause harmful interference
to radio communications. However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or television reception, which
can be determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

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Appendix D: Safety notices (continued)
Warning
Any changes or modications not expressly approved by Origin Effects Limited could void the user’s
authority to operate the equipment.
For customers in Canada: This Class B digital apparatus complies with Canadian Interference
Regulations CAN ICES-3(B)/NMB-3(B). Pour le Canada: Où indiquée sur le produit: Cet appareil
numérique de la classe B est conforme à la norme CAN ICES3(B)/NMB-3(B) du Canada.
RoHS
The crossed out wheely bin symbol indicates this product is classied as Waste Electrical and Electronic
Equipment (WEEE) in the European Union and should not be discarded with household waste. Other
territories may vary. Contact your local authority or Origin Effects for more information.
WARNING: This product can expose you to chemicals including nickel, which is known to the
State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov
Evaluation of apparatus based on altitude not exceeding 2000m. There may be some potential
safety hazard if the apparatus is operated at altitude exceeding 2000m.
Evaluation of apparatus based on temperate climate conditions only. There may be some
potential safety hazard if the apparatus is operated in tropical climate conditions.
Appendix E: warranty
This product is covered by a 2-year manufacturer’s warranty from the date of purchase. This applies only
to original purchasers who have bought their product from an authorised Origin Effects dealer or directly
from Origin Effects.
All returns or servicing should be arranged through the original dealer. Proof of original ownership may
be required in the form of a purchase receipt.
For full warranty details visit www.origineffects.com/warranty.