Keeley HYDRA User manual

INSTRUCTION MANUAL

22
TABLE OF CONTENTSTABLE OF CONTENTS
Introduction.......................................................................3
Primary Controls..............................................................4
Secondary Controls........................................................5
Footswitch Controls.......................................................6
Tap Tempo...........................................................................7
Infinite Hold Feature......................................................7
Trails or True Bypass......................................................7
All Wet / Dry Mode..........................................................7
Buffered Bypass...............................................................7
Creating and Saving Presets.....................................8
Expression Pedal Use....................................................9
Factory Reset....................................................................9
Suggested Settings......................................................10
User Settings.....................................................................11
Technical Specifications...............................................11
Quick Start Guide...........................................................12
Introduction.......................................................................3
Primary Controls..............................................................4
Secondary Controls........................................................5
Footswitch Controls.......................................................6
Tap Tempo...........................................................................7
Infinite Hold Feature......................................................7
Trails or True Bypass......................................................7
All Wet / Dry Mode..........................................................7
Buffered Bypass...............................................................7
Creating and Saving Presets.....................................8
Expression Pedal Use....................................................9
Factory Reset....................................................................9
Suggested Settings......................................................10
User Settings.....................................................................11
Technical Specifications...............................................11
Quick Start Guide...........................................................12
Keeley Electronics, Inc. 2020Keeley Electronics, Inc. 2020

3
HYDRA STEREO REVERB & TREMOLO
THE KEELEY HYDRA - STEREO REVERB & TREMOLO
The HYDRA combines high-fidelity Reverb and Tremolo to add space and dimension to
your guitar, bass, or keyboard signal. After the team at Keeley completed the ECCOS, we
wanted to craft the perfect companion pedal, and we did just that with our new, feature-rich
blue box. Bathe your sound in Spring, Plate or Room Reverb, then add tap-tempo enabled
Harmonic, Vibrato, or Sine Wave Tremolo with the press of a button. You can easily change
the order of effects or the character of the Tremolo or Reverb with the HYDRA’s smart
Alt Controls. You can even create an Infinite Hold Reverb Trail! Save up to three presets
with ease using our intuitive save feature. Engage Reverb Trails on the fly, no more internal
dip switches. The Hydra can be used with pro remote switching systems and offers both
TRS Expression Pedal and External Tap-Tempo inputs. The HYDRA is a complete end-of-
pedalboard solution that fits perfectly in any musician’s rig, regardless of genre. Experience
next-level processing power in this pedalboard-friendly enclosure. The sky, or more
appropriately, the ocean floor, is the limit with the new Keeley Electronics HYDRA!

4
PRIMARY CONTROLS
1
2
3
4
5
1RATE - Sets the rate of the Tremolo. Turn left for
slower speeds, right for faster.
2DEPTH - Sets the maximum amount of volume
reduction for the Tremolo.
4COLOR -
Sets the tone of the Reverb. Pressing this
control grants access to alternative settings and
presets.
5MIXER -
Sets the level of the Reverb. Turn left for a
lower Reverb volume, right for higher Reverb volume.
6TOGGLE SWITCH -
Selects between Spring, Plate
and Room Reverb types.
3DWELL -
Sets the length of the Reverb trail. Turn left
for less, right for more.
6

5
HYDRA STEREO REVERB & TREMOLO
Hold down the COLOR knob while
manipulating other controls to access
secondary controls.
2
3
4
1
5
6
SECONDARY CONTROLS
Access four alternate tone and time shaping controls by pressing and holding the COLOR control while turning other controls
1COLOR - Press and hold the COLOR knob while
manipulating the other controls to change the settings
marked in dark grey on the HYDRA.
2
TREM SYNC - Sets the stereo output of the Tremolo for either panning,
synced, or wet/dry. CCW of noon is stereo panning where the signal will
alternate between the two outputs. At noon both outputs will be in sync,
pulsing at the same time. CW of noon will run the dry signal through the
Stereo Out jack and Trem through the Mono Out jack.
3TREM LEVEL - Controls the output volume of the Tremolo.
At full CW there is a +6db boost to compensate for the
perceived volume drop inherent in Tremolo.
4WET/DRY - Sets the stereo output of the Reverb for either
stereo Reverb or a wet/dry setup. CCW of noon is stereo
Reverb while CW of noon is the dry signal only on the
Stereo Out and Reverb on the Mono Out.
5
REVERB MODIFIER - Modifies the Reverb depending on the mode
selected. On Spring this will control the spring age, being bouncier and
more pronounced echoes with the control full CW and more diffused
and smooth at full CCW. On Plate this sets the amount of shimmer
introduced into the Reverb. Full CCW is no shimmer with full CW giving
a large cascade of octave up. On Room this controls the room size, going
from a small closet at full CCW to a large cavern at full CW.
6
TOGGLE SWITCH - Selects between Sine, Harmonic, and
Vibrato Tremolo.
FX ORDER - To change the order of effects, press and hold
the COLOR knob and double tap the BYPASS switch for the
effect to be first in the chain.

FOOTSWITCH CONTROLS
Smart Controls at the press of a button
6
REMOTE SWITCHING
The Tremolo and Reverb Bypass switches can be controlled remotely
through the remote jack. Using a TRS cable, the tip controls the Reverb
while the ring switches the Tremolo. The unit is set up to be used with
momentary switches by default. It can be put into latching mode by
holding down the Tremolo Bypass switch while applying power to the
unit. Doing this again will put the unit back into momentary mode.
While in latching mode, the bypass switches on the unit will behave
differently than when in momentary mode. The Tremolo Bypass
switch on the unit will no longer turn the Tremolo on or off. Instead,
this switch is solely used for presets (Double tap to enter preset
mode, hold switch to save preset, and single press to select preset).
The Reverb switch on the unit is tied directly to the tip of the remote
switching. Due to this, the on-unit Reverb Bypass switch will act as if it
has been hit twice for every one button press.
Preset mode can still be accessed by double tapping the Ring switch.
Pressing the Tip switch will scroll through the presets. Pressing the
Ring switch again will recall the selected preset.
EXTERNAL TAP
Plugging a mono cable into the expression jack will allow
the use of an external switch for tap-tempo control.
MODE SWITCHING
Double tapping the COLOR knob will put the unit into mode
select. The Mode LEDs will illuminate to show where both
the Reverb and Tremolo modes are set. The Tremolo LED
will blink at the current tempo. To change Tremolo mode
simply scroll through using the Tremolo Bypass switch.
Similarly, use the Reverb Bypass switch to toggle through
the Reverb modes. Once the modes are set, double tap the
COLOR knob to exit. Alternately, it will automatically time
out and exit 8 seconds after the last button push.
12
1
2
TREMOLO - Single tap to turn the Tremolo on
or off. Pressing and holding the Tremolo switch
for approx. 1 second will put the Tremolo into
Tap Mode. The current mode LED will flash at
the rate indicating that the Trem is in tap mode.
Pressing the Trem Bypass switch more than once
will change the rate of the Trem. This mode times
out in 5 seconds. You can also exit this mode by
holding the Trem Bypass Switch for 1 second.
REVERB - Single tap to turn the Reverb on or
off. Pressing and holding the REVERB switch for
approx. .5 seconds will freeze the signal going
into the reverb for infinite sustain.

7
HYDRA STEREO REVERB & TREMOLO
Pressing and holding the Tremolo Bypass switch for approximately 1 second will put the Tremolo into Tap Mode. The current
mode LED will flash at the rate indicating that the Tremolo is in Tap Mode. Pressing the Tremolo Bypass switch more than once
will change the rate of the Tremolo. If the Tremolo Bypass switch has not been pressed for more than 5 seconds the Tremolo
will exit out of Tap Mode. Additionally, pressing and holding the Tremolo Bypass switch for 1 second will exit Tap Mode.
The unit can be put into buffered bypass by pressing and holding the COLOR knob and the Reverb Bypass switch for
approximately 3 seconds. Repeat the process to change back to True Bypass. The Mode LED and Reverb Bypass LED will flash
twice to indicate that the change has been made.
While in buffered bypass, the unit will sum both inputs to the mono output if no jack is connected to the stereo output.
Note: Summing the outputs to mono may have unexpected results depending on what is plugged into the Right input.
Pressing and holding the Reverb Bypass switch for approx. 0.5 seconds will freeze the signal going into the Reverb for infinite sustain.
Trails can be achieved by pressing and holding both the Reverb and Tremolo bypass switches for roughly 2 seconds. The
Reverb Bypass LED and the current Mode LED will flash twice to indicate a successful change.
The dry signal can be toggled on and off by holding the Tremolo Bypass switch and COLOR knob while applying power to the unit.
TAP TEMPO MODE
Control the speed of the HYDRA’s Tremolo with our handy Tap Mode
BUFFERED BYPASS
INFINITE HOLD
Freeze the HYDRA’s Reverb for as long as you wish with intuitive Infinite Hold
TRAILS
Trails or True Bypass - Switch on the fly and choose what works best for you
ALL WET / DRY MODE
Choose All Wet or Dry Mode quickly and easily

8
PRESET SELECT MODE - To enter Preset Select
Mode, quickly double tap the TREMOLO switch or
tap the COLOR knob once. Preset LEDs will begin
to flash. The REVERB switch or MODE Select switch
advances through the presets. Tap TREMOLO
again to select the preset currently flashing. Hold
TREMOLO to overwrite the selected preset.
CHANGES TO A PRESET - Any changes made to
a parameter will turn OFF the preset LED. Double
tap the TREMOLO switch again to once again enter
preset select mode. Cycle through the presets by
using the REVERB or MODE switch, then hold the
TREMOLO switch to save the changes made to the
selected preset.
The HYDRA features 3 preset locations. In addition,
you can access a What You See Is What You Get
(WYSIWYG) mode by entering Preset Select Mode,
then scrolling through the preset locations until all
3 Preset LEDs are blinking, then select it by tapping
the TREMOLO switch. This is a great way to exit any
of the three preset settings and go back to where
the controls are currently set.
The three lights in the middle of the HYDRA are
preset indicators, which will correspond with the
currently engaged preset. In WYSIWYG mode, all
three are constantly lit.
CREATING AND SAVING PRESETS

9
HYDRA STEREO REVERB & TREMOLO
EXPRESSION PEDAL INPUT
You must use a TRS (stereo) expression pedal with the
HYDRA. If you use a mono cable (or volume pedal), the
HYDRA will not power on.
When a TRS (stereo) expression pedal is inserted, the
expression pedal defaults to controlling the RATE control of
the TREMOLO.
Note: Plugging a mono cable into the TRS EXP. PEDAL jack
will allow the control of the Tap Tempo.
CLEAR ALL EXPRESSION SETTINGS
To clear ALL expression pedal settings, enter Expression
Pedal Mode by holding the COLOR knob for 2 seconds. Once
in Expression Pedal Mode, hold TREMOLO footswitch for 2
seconds to clear ALL expression pedal settings and reset
them to default. Once finished, exit Expression Pedal Mode
by holding the COLOR knob for 2 seconds.
FACTORY RESET
Hold down the COLOR knob + TREMOLO + REVERB
footswitches while applying power to the unit.
All LEDs will flash in succession and all controls, secondary
controls, modes, memory and presets will
return to default settings.
You will see all of the lights on the HYDRA cycle, indicating
that the Factory Reset is complete.
Note: When making these adjustments, it helps to place the
HYDRA on a flat surface, such as a pedalboard or a table top.
EXPRESSION PEDAL USE
TO ASSIGN A PARAMETER
1. Hold COLOR knob for 2 seconds to enter Expression Mode.
2. Set connected expression pedal to heel-down.
3. Turn a HYDRA control knob to the desired
heel-down setting.
4. Set the expression pedal to toe-down.
5. Turn the same control knob to the desired
toe-down position.
6. Hold COLOR knob for 2 seconds to save your settings.
Note: You can set multiple parameters at once to be
controlled with your expression pedal. You can set partial
ranges, reassign ranges, or even reverse heel/toe positions in
this mode. The sky is the limit!
TO UNASSIGN A PARAMETER
1. Hold COLOR knob for 2 seconds to enter Expression Mode.
2. Set connected expression pedal to heel-down.
3. Turn each knob a small amount to let the HYDRA know
you don’t want the control to be ‘expression controlled’.
Don’t touch controls still assigned to the expression pedal.
4. Set the expression pedal to toe-down.
5. Hold the COLOR knob for 2 seconds to unassign and save.
Note: Any parameters that were not moved will maintain
their previous expression status.
Note: You can save expression pedal setting to any of the 3
HYDRA preset locations.

10
FACTORY PRESET HYDRA SETTINGS
Getting started with the HYDRA Stereo Reverb & Tremolo
HARMONIC
TREMOLO
SPRING
REVERB
SINE
TREMOLO
PLATE
REVERB
VIBE
TREMOLO
ROOM
REVERB
TIP: HOLD DOWN THE COLOR KNOB TO ADJUST THE ALT CONTROLS
WARM SPRING
& TREM
DEEP BLUE
DREAMING
VINTAGE
SUN

TECHNICAL SPECIFICATIONS
11
YOUR HYDRA SETTINGS
Write in your favorite settings for the HYDRA Stereo Reverb & Tremolo
TIP: HOLD DOWN THE COLOR KNOB TO ADJUST THE ALT CONTROLS
HYDRA STEREO REVERB & TREMOLO
9V Neg-Tip DC Supply
115mA
Input Impedance, 1M / Output Impedance, 10K
True-Stereo Input and Output
True Bypass or Buffered Trails
Analog Dry-Thru Blend

12
TREMOLO MODE
RATE - Sets the rate of the Tremolo
DEPTH - Sets maximum amount of volume reduction
of the Tremolo
TREMOLO FOOTSWITCH - Turns the Tremolo on and off
REVERB MODE
DWELL - Sets the length of the Reverb trail
COLOR - Sets the tone of the Reverb trail
(Can also be pressed and held to access alt controls)
MIXER - Sets the level of the Reverb
REVERB FOOTSWITCH - Turns the Reverb on and off
MINI TOGGLE - Selects between Spring, Plate, and
Room Reverb Types
(Hold COLOR knob and use Mini-Toggle to select
Sine, Harmonic, or Vibrato Tremolo)
ALT CONTROLS
Hold the COLOR knob down while adjusting
RATE, DEPTH, DWELL, and MIXER knobs
to engage the
TREM SYNC, TREM LEVEL, WET/DRY, and REVERB
MODIFIER controls, respectively.
PRESETS
SELECT PRESET - Double-tap TREMOLO footswitch,
then tap REVERB footswitch to cycle through presets.
Tap TREMOLO footswitch again to select chosen preset.
SAVE PRESET - Once changes to the control knobs
have been made (including alt. controls), double tap the
TREMOLO footswitch or press the COLOR knob. Cycle
to the desired preset location with
the REVERB footswitch, then hold the TREMOLO
footswitch to save your changes.
INFINITE HOLD
When Reverb is engaged, hold the REVERB footswitch
to enter Infinite Hold mode. Release to exit IH.
TRAILS
Press and hold the TREMOLO and REVERB
footswitches for 2 seconds.
TREMOLO TAP TEMPO
Press and hold the TREMOLO footswitch for 1 second.
Tap TREMOLO footswitch 2-3 times to set tempo.
HYDRA QUICK START GUIDE
Jump right in to the HYDRA Stereo Reverb & Tremolo
FOR MORE INFORMATION, VISIT RKFX.COM