UAFX Woodrow '55 Instrument Amplifier Manual

This article contains complete operating instructions for the UAFX Woodrow '55 amp pedal.

A Letter From Bill Putnam, Jr.

Congratulations on your new UAFX pedal. We know that buying any new piece of gear requires an investment of time and money, and we aim to make your investment pay off!

At UA, we are dedicated to the idea of building “instant classics” — the type of music and audio gear that delivers album-worthy sounds to inspire you for decades.

UAFX pedals represent more than 20 years of research into vintage analog effects, coupled with next-generation digital engineering and rock-solid reliability.

Please let us know how we’re doing. Feel free to reach out to us via our website, and via our social media channels.

Thank you for your support, and enjoy your sonic exploration!


Bill Putnam Jr.



Woodrow '55 Quick Start


Download Woodrow '55 Quick Start



Woodrow '55 Overview

Experience raw tube tones from the dawn of electric guitar.

The UAFX Woodrow '55 Instrument Amplifier pedal gives you the legendary American tweed tube amp sounds used by artists and producers for decades, from The Eagles to Chuck Berry to Neil Young.

Built on powerful dual-engine processing and UAD modeling expertise, the Woodrow '55 effects pedal packs sweet cleans, rich overdrive, and grungy distortion.

Now You Can

  • Get the best emulation of a mid-'50s American tweed amp ever packed into a pedal
  • Go from dapper to dangerous with classic tube tones
  • Take world-class studio amp sound anywhere, complete with mic/speaker pairings and preamp boosts
  • Download artist tones, customize features, explore presets , and more with UAFX mobile app

Experience Perfect Tube Amp Growl, Stage and Studio

Whether it's replacing your amp rig and going direct to front-of-house on stage, or recording tracks into your DAW — Woodrow '55 gives you the inspiring, album-ready tones of an expertly miked "golden unit" vintage tweed amp, within seconds.

Get Hot-Rodded Sounds

Take your rowdy tweed tones further using tried-and-true British speaker swaps and boosts — including preamps from the iconic KORG SDD-3000 rack unit and Maestro EP-3 tape delay — at the flip of a switch.* Only Woodrow '55 puts authentic tube growl and hot-rod mods under your chucks, docs, or crocs.

* Product names used herein are trademarks of their respective owners, which are in no way affiliated with Universal Audio Inc. These name(s) are used solely to identify products studied in the creation of the sound models found in Woodrow '55 Instrument Amplifier.

Key Features

  • Powerful UAFX dual-engine delivers the most authentic mid-'50s American tube combo sound ever placed into a stompbox
  • Includes the world's best speaker cabinet, mic, and room tones derived from the award-winning OX Amp Top Box
  • Features "hot rod" boosts, classic speaker swaps, plus free additional downloadable cabinets and mics upon registration
  • Bypass cabinet/mic emulations and use in front of your amp for added tonal flavor and overdrive sounds
  • UAFX mobile app lets you customize footswitches, recall and archive presets, unlock additional features, download artist presets, and more
  • Timeless UA design and craftsmanship, built to last decades

UAFX Control software

UAFX Control is the companion software for UAFX pedals.To get UAFX Control software, go here.

UAFX Control Desktop App – The UAFX Control desktop app is for pedal registration, getting free bonus speaker cabinets, and firmware updates. Firmware updates for UAFX may be provided to improve or add functionality, and are installed over a USB connection to a computer, using a USB-C cable (not included).

UAFX Control Mobile App –The UAFX Control mobile app is for preset management, getting free bonus effects and speaker cabinets, global settings such as footswitch modes, and registration.

Free Bonus Speaker Cabinets

Register your pedal with UAFX Control software to get three bonus speaker cabinets for more great tone options. To get UAFX Control, visit:



Woodrow '55 Power

To learn how to power your UAFX pedal, go here.



Woodrow '55 Connections

To learn how to wire your UAFX pedals, go here.




Woodrow '55 Operation

Live Mode and Preset Mode

Woodrow '55 is set up in Live | Preset mode by default. You can use the UAFX Control mobile app to change footswitch assignments.

In Live mode, the sound reflects the current positions of the knobs, switches, and LEDs on the pedal, and the left footswitch toggles the Live mode effect on/off.

In Preset mode, you hear the settings that are stored as a preset, and the current positions of the knobs and switches do not reflect the sound. Instead, all knob and switch positions are internally set to their stored positions, and the right footswitch toggles the preset effect on/off.

You can store a preset you’ve made with your own settings by holding down the STORE switch until the green PRESET footswitch LED blinks rapidly (about 0.5 seconds)

Live Mode

To enter Live mode, press the left footswitch. Press the left footswitch again to toggle the live effect on/off. The left footswitch LED is lit red when the Live mode effect is on.


Preset Mode

To enter Preset mode, press the right footswitch. Press the right footswitch again to toggle the preset on/off. The right footswitch LED is lit green when the preset is on.


Note: The left and right footswitch functions can be changed in the UAFX Control mobile app.

Stored Preset

You can store a preset on your UAFX pedal, and recall it using the right footswitch. All presets you store, and other artist and factory presets, are available in the UAFX Control mobile app.

When you store a preset while in Live mode, the position of all knobs and switches on the pedal are saved. When you make a great sound in Live mode, storing it is as easy as holding down the STORE switch until the green PRESET footswitch LED blinks rapidly (about 0.5 seconds).

When you store a preset while in Preset mode, only those knobs and switches that have changed since you loaded the preset are saved. So, when saving in Preset mode, what you hear is what is saved, and not the current positions of the knobs and switches.

To store your sound as a preset

  1. Set your sound as you want it stored in the preset.
  2. Press and hold the STORE switch in the down position until the green PRESET footswitch LED blinks rapidly (about 0.5 seconds).

Preset Notes

  • The settings for Preset mode and Live mode are completely independent.
  • When you move a knob or switch in Preset mode, the settings for the sound immediately jump to the new knob or switch position.
  • You can view and audition all of your pedal’s presets with the UAFX Control mobile app.
  • Presets can only be stored when the pedal is not bypassed.



Woodrow '55 Controls

The following controls are available on Woodrow '55.

Instrument Volume (INST VOL) and Mic Volume (MIC VOL)

Adjusts the amp’s instrument and mic channel gain. The instrument channel is slightly brighter and more aggressive as you turn it up, and the mic channel is darker and cleaner, with more bottom end. As you increase one or both volume controls, the character of the amp changes, becoming more overdriven and compressed.

The available clean range of the volume controls has been slightly expanded, and the Output control provides extra makeup gain. All the gain of the original tweed amp is still there, but the ability to dial in clean sounds is improved — something that could be difficult to achieve on the original amp.

Woodrow’s channels are automatically “jumped” or ganged together when you turn both volume controls up. To hear either the Instrument or Mic channel alone, turn the other volume control all the way down. Woodrow emulates plugging in to the Hi input with the Stock and EP-III boosts, and plugging in to the Low input with the KP-3K boost.

Note: These are the “Volume” controls on the original amp. For clean “post-amp” volume adjustments, use the Output control.


Adjusts the output level from the pedal. When the Output volume is set at noon (running direct or into other pedals), it will be roughly the same level as your bypassed volume.

Output volume allows you to set the level for your setup. This control is not available on the original amplifier.


Adjusts the amount of room tone mixed into the signal.

Notes and tips

  • Room amount only affects your sound when you use a speaker cabinet. When the speaker cabinet is bypassed, Room has no effect. The Speaker LED blinks rapidly to indicate the knob is inactive.
  • Set Room to noon for a good starting point, and add or remove room to taste. Setting Room fully off is like recording your amp in an isolation booth. Turning up the Room knob adds ambience from the room microphones set up in the tracking room of a studio.
  • There is no fully wet Room sound.


Adjusts the amp’s treble frequencies. The Tone control is interactive with the gain of the amp — as you turn up the Tone, the pedal’s overdrive and distortion increase. Start with this around noon for a cleaner sound, and increase it for more gain and brightness.

Boost knob

Adjusts the amount of boost applied to the input of the amp. See Woodrow '55 Boosts for details about the available boost types.

Note: When the Boost knob is rotated fully counter-clockwise, no boost is applied.


Push this switch up or down to change the speaker cabinet and microphone. When you push the switch repeatedly in the same direction, the pedal cycles through all available speaker cabinets.

Tip: Register your pedal to get free bonus speaker cabinets.

Speaker Type LED

The currently selected speaker cabinet is indicated by this LED. A red LED indicates that the effect printed on the pedal is selected. A bonus speaker cabinet is selected when an LED is green (the bonus speaker cabinets don't have labels).

When the LED is off, the amp is active but no speaker simulation is applied.

Tip: When playing through a real guitar amplifier and speaker cabinet, you might want to bypass the speaker cabinet emulation by pressing the pedal's Speaker switch until its LED is unlit.


To store a preset, press and hold the STORE switch in the down position until the green PRESET footswitch LED blinks rapidly (about 0.5 seconds).

Boost Switch

Woodrow '55 includes three boost types: two boost circuits based on classic vintage boost and amp combinations, and a clean boost. These boosts each provide unique character and gain.

  • STOCK is the stock amp circuit, and the Boost knob increases clean boost to the amp’s High input.
  • KP-3K provides boost from an '80’s rack delay preamp. This boost setting also emulates plugging int to the amp’s Low input to provide a cleaner starting point.
  • EP-III adds boost from a vintage EP-III preamp to the amp’s High input.

Use the Boost switch to select the Boost type, and the Boost knob to add gain. See Woodrow '55 Boosts for more details about the available boosts.

Note: When the Boost knob is rotated fully counter-clockwise, no boost is applied. However, when the Boost switch is set to KP-3K, the amp is switched to the mic input.

Left Switch LED

By default, the left footswitch LED is lit red when Live mode knob and switch settings are active.

Other states for the left footswitch LED are detailed in Footswitch Modes.

Left Footswitch

By default, press to toggle the Live mode sound on/off with the current knob and switch settings.

This footswitch can also toggle other options, depending on the footswitch mode, as detailed in Footswitch Modes.

Preset Footswitch LED

The preset footswitch LED is lit green when stored settings are active. There are other modes for the right footswitch LED, as detailed in Footswitch Modes.

Right Footswitch

By default, press to toggle the Preset sound on/off.

This footswitch can also toggle other options, depending on the pedal footswitch mode, as detailed in Footswitch Modes.



Woodrow '55 Footswitch Modes

With the UAFX Control mobile app, you can change the operation of your pedal and your pedal’s footswitches for your amplifier setup and performance preferences. For example, if you use Wodrow '55 as your main amplifier, and you don’t need to bypass your pedal, you can use a footswitch mode to toggle boost on and off, and to toggle between live and preset sounds.

For more details about footswitch modes and how to enable them, see Woodrow '55 Settings in the UAFX Control App.



Left Footswitch

Right Footswitch

Live | Preset

Live mode on/off

Preset on/off

Boost | Live/Preset

Boost on/off

Live mode/Preset toggle

4-cable mode

Live mode on/off

*If Live and Preset are off, you hear your amp’s sound.

Preset mode on/off

*If Live and Preset are off, you hear your amp’s sound.



Woodrow '55 Speaker Cabinets

Each speaker, cabinet, and mic setting has a unique sound. Toggle up or down through the list with the Speaker switch. When you register your pedal with UAFX Control software, you get three free bonus speaker cabinets (green LEDs).


Note: The speaker cabinet labels on the pedal apply only when the speaker LED is red. When the speaker LED is green, the active speaker name is visible in the UAFX Control mobile app.


Switch Label

LED Color

Active Speaker






15W Celestion Blue in the 1x12 tweed combo, mic'd with a 67 condenser mic.

Darker than the stock speaker.




Stock Jensen P12R in the 1x12 tweed combo, mic'd with a 57 dynamic mic.

Stock speaker, on the thinner and less aggressive side.




25W Celestion Greenback in the 1x12 tweed combo, mic'd with a 57 dynamic mic.

More modern and thick with a clear high end, fuller with distortion pedals or higher gain.




Marshall 4x12 with Celestion V30 speakers, mic'd with a 421 dynamic mic.

More bottom end chunk and fullness. Great for a big lead sound or thick rhythm sounds.




Fender 4x10 Bassman cab with Jensen P10R speakers, mic'd with a 57 dynamic mic.

Great scooped, high fidelity sound when used clean. Use with the KP-3K boost and low gain for clean, somewhat pristine sounds.




Fender 1x12 cab with vintage JBL D-120F speaker, mic'd with a 414 condenser mic.

Bright, hi-fi, midrangey.




No emulated cabinet

Use with real guitar cabinet or external cabinet emulation.

* Product names used herein are trademarks of their respective owners, which are in no way affiliated with Universal Audio Inc. These name(s) are used solely to identify products studied in the creation of the sound models found in Woodrow '55 Instrument Amplifier.



Woodrow '55 Boosts

Each boost has a unique sound and effect. To increase the amount of gain and the effect of the boost, rotate the Boost knob clockwise. When the boost knob is turned all the way down to OFF, the boost is transparent and has no effect on amp color and gain. As the boost knob is turned up






Renowned preamp boost from an 80’s digital delay, made famous by The Edge.

Bright and detailed. When this boost is engaged, the Low input is used, providing a cleaner sound before the boost or pedals are engaged.


Clean “curve” boost.

Clean gain without added distortion. As you increase the boost level, midrange and treble increase slightly and bass decreases slightly, to prevent flubby or mushy distortion. This boost uses the High input.


Preamp section from an EP-III tape echo.

Thick and warm with plenty of additional gain. As soon as you turn the boost knob past zero it thickens the sound. This boost uses the High input.


Woodrow '55 tone shortcuts

Try these boost and speaker cabinet settings for classic tone pairings.

  • JP12 + CLEAN - Stock factory pairing, start with the tone halfway up.
  • Vee30 + EP-III - Fat lead setting, turn up the boost and gain for fuzz-like qualities.
  • B-Man + KP-3K - Hi-fi clean sound with the gain set low.

Factory and Artist presets offer many more great-sounding speaker cabinet and channel pairings. Use the UAFX Control mobile app to access presets.



Woodrow '55 Settings in the UAFX Control App

With the UAFX Control app, you can change the operation of your pedal and your pedal’s footswitches for your amplifier setup and performance preferences.

Tap Settings at the bottom right of the screen to access the settings for a pedal. You may need to scroll down on this screen to see all available settings.

Woodrow '55 bonus speaker cabinets

After registration, the Vee30, B-Man, and JB120 speaker cabinets are added to the pedal. To select these speaker cabinets, push the Cab switch until the top, middle, or bottom LED is lit green.


Woodrow '55 footswitch modes

Footswitch modes can be changed to suit your preferences. Using the UAFX Control app, you can configure the switches to toggle live mode and preset mode, toggle between your amp’s preamp and the pedal’s preamp in 4-cable mode, and to toggle the boost on and off.

Choosing a footswitch mode

To select a footswitch mode, open the Settings screen. Then tap the current footswitch mode (colored bar) and choose a mode from the drop menu.

Note: See Assigning the preset or live sound for information about how to set the pedal sound when you use a footswitch mode that cannot be bypassed.


The following Woodrow '55 footswitch modes can be selected with the UAFX Control app.

Live | Preset


In Live | Preset mode, you can access Live mode (knobs and switches) and the stored preset.

  • Left Footswitch toggles the Live sound on/off
  • Right Footswitch toggles the stored preset on/off
  • Pedal can be bypassed
  • 4-cable mode is available

Boost | Live/Preset


In Boost | Live/Preset mode, you can switch Boost on and off, and toggle between Live mode (knobs and switches) and the stored preset.

  • Left Footswitch toggles Boost on/off
  • Right Footswitch toggles between Live mode (red LED) and the stored preset (green LED)
  • Pedal is always on and cannot be bypassed
  • 4-cable mode is not available

Woodrow 4-cable mode

4-cable mode lets you add another switchable channel to any real guitar amplifier that has an effects loop. This special mode lets you switch between your guitar amplifier's built-in preamp section and the sounds in your pedal.

Warning: Turn off your amplifier before wiring the pedal and enabling 4-cable mode. If you enable 4-cable mode with incorrect wiring, you can cause extreme feedback.

To learn how to set up and operate 4-cable mode, go here.

Note: The Room control does not have any effect in 4-cable mode. 


Woodrow '55 Specifications

Power requirements

(power supply sold separately)

Isolated 9VDC, center-negative, 400mA minimum


2 x ¼” unbalanced TS (input 2 for stereo connections and 4-cable mode)


2 x ¼” unbalanced TS (output 2 for stereo connections and 4-cable mode)

Input impedance

500 Kilohms (Mono In)

1 Megohms (Stereo In)

Output impedance

500 Ohms

Maximum input level

12.2 dBu

Maximum output level

12.1 dBu

Frequency response

20 Hz to 20 kHz, ±1 dB

USB Type-C

For registration and firmware updates via computer

Wireless technology

Transmitted Frequency Range

Maximum Output Power

Bluetooth v5

2.400 GHz – 2.4835 GHz

+4.35 dBm


(with knobs and protrusions)

Height: 2.56 inches, 6.5 cm

Width: 3.62 inches, 9.2 cm

Depth: 5.55 inches, 14.1 cm

Weight (unboxed)

1.24 lbs

0.567 kg

Note: All specifications are subject to change without notice.



Woodrow '55 Safety

safety-symbol-exclaim.pngCaution: To help maintain the safety of your product, the chosen power supply must be a certified power supply complying with Limited Power Source (LPS) requirements with the following characteristics and electrical ratings: Isolated 9VDC, center-negative, 400 mA minimum, 2.1x5.5 mm barrel connector. Additional details at

safety-symbol-book-info.pngBefore using this unit, be sure to carefully read the applicable items of these operating instructions and the safety suggestions. Afterwards, keep them handy for future reference. Take special care to follow the warnings indicated on the unit, as well as in the operating instructions.

  • Read the instructions.
  • Keep these instructions.
  • Heed all warnings.
  • Follow all instructions.
  • Do not use this apparatus near water.
  • Clean only with dry cloth.
  • Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
  • Do not install near any heat source such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
  • Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other.
  • Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
  • Only use with attachments/accessories specified by the manufacturer.
  • Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
  • Woodrow '55 does not contain a fuse or any other user-replaceable parts.
  • A compliance marking label is provided on bottom of the unit.

United States Class B Manual Statement

NOTE: 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 and correct the interference by one or more of the following measures:

  • Reorient or relocate the receiving antenna.
  • Increase the separation between the equipment and the 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.

Japanese Class B Manual Statement




This is Class B equipment. Although this equipment is intended for use in residential environments, it could cause poor reception if used near a radio television receiver. Please follow instructions in the instruction manual.

Korea KCC: 해당 무선설비는 전파혼신 가능성이 있으므로 인명안전과 관련된 서비스는 할 수 없습니다.

License exempt. This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation of the device.

Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts de licence. L'exploitation est autorisée aux deux conditions suivantes : (1) l'appareil ne doit pas produire de brouillage, et (2) l'utilisateur de l'appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le fonctionnement.

safety-symbol-trash.pngUsed electrical and electronic equipment should not be mixed with general household waste. Please dispose in accordance with local regulations.

  • IEC 62368-1
  • FCC ID: 2AXKQ2029
  • IC ID: 26610-2029


Hereby, Universal Audio, Inc. declares that the radio equipment type Bluetooth LE Device (Residential) is in compliance with Directive 2014/53/EU. The full text of the EU declaration of conformity is available at the following internet address: Signed EU Declaration of Conformity.pdf

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