The Oscillator Devices HYDRA4X is a MIDI controlled matrix loop switcher with four reorderable loops in a pedalboard friendly package1. Where a conventional loop switcher has its effects loops in a fixed order, the HYDRA4X is built around a switch matrix, which the maker describes this way:
"The heart of the HYDRA4X is a switch matrix. That means that any input can be connected to any output."
That means a player can put an overdrive after a delay in one preset and before it in the next, without repatching cables. The unit also runs loops in parallel with each other or with the clean signal, preserves delay and reverb trails when loops switch off, and adds two volume control blocks, a feature Oscillator Devices says it introduces to the MIDI loop switcher market1. It is developed and built by Oscillator Devices in Germany2.
How the matrix works
A conventional loop switcher passes the signal through its loops in a fixed order: loop 1, then loop 2, then loop 3, then loop 4. The HYDRA4X's switch matrix instead lets any input connect to any output, so the four loops can be arranged in any order per preset2. Loops can also run in parallel, either with each other or with the clean signal, which is useful for effects that sound better mixed against a dry signal rather than stacked in series. The only restriction the maker states is that parallel loops have to be consecutive2.
The signal path is protected by high quality, low noise buffers with high headroom, specified at 8Vpp / 5.6Vrms1, and the unit uses high quality Amphenol sockets2.
Volume control
The HYDRA4X has two volume control blocks. One is fixed right before the output; the other can either be placed at the very beginning of the chain or tied to one of the loops2. Both can be set to mute or anywhere from -24dB attenuation to +12dB boost, with attenuation in 3dB steps and boost in 2dB steps2.
| Volume block | Placement | Range | Steps |
|---|---|---|---|
| Block 1 | Fixed right before the output | Mute, or -24dB to +12dB | 3dB down, 2dB up |
| Block 2 | At the very beginning, or tied to one loop | Mute, or -24dB to +12dB | 3dB down, 2dB up |
Trails, presets and MIDI
When a delay or reverb loop switches off, the HYDRA4X preserves the tail. As the maker explains2:
"This is realized by only disconnecting the input of the effects and mixing the output with the signal path."
The loop's input is cut so no new signal enters, but its output keeps feeding the mix until the tail decays naturally2.
Settings can be saved to one of 127 presets1. Saving is a short process:
- Set up everything using the buttons on top.
- Press and hold the white button.
- Send a PC (program change) message.
- The settings are saved to that PC message2.
The MIDI connections follow the official MIDI specification for MIDI TRS, using MIDI TRS Type A on a 1/8" (3.5 mm) stereo jack plug, and are compatible with Morningstar MIDI TRS connections2. The unit works with all MIDI 1.0 compliant controllers1. Switching is fast: the time between sending a MIDI command and the switch matrix being fully set is a maximum of 15ms2.
Setup without a computer
All advanced functionalities are accessible with the buttons on top of the HYDRA4X, with no computer software needed13. The user manual and quick start documents cover firmware version 1.1.1 (September 2026)2, and the maker's firmware page lists version 1.1.2 for the HYDRA4X4.
Physical design
The enclosure keeps a small footprint of 112mm x 62mm and a height of 46mm, achieved by using stacked jacks, and it weighs 0,32 kg1. The buttons on top can be locked so no unwanted changes happen when the unit is mounted under a pedalboard2.
The maker's product pages give slightly different footprint figures for the HYDRA4X: 112mm x 62mm on one page and 112 x 67 x 46 mm on another, both dated October 2026.
Videos
Oscillator Devices
Questions
Does the HYDRA4X need computer software to set up?
No. Oscillator Devices says all advanced functionalities are accessible with the buttons on top of the unit, with no computer software needed. Loop order, parallel routing, volume placement and preset saving are all done from the pedal itself.
Does the HYDRA4X support trails on delay and reverb loops?
Yes. Trails are realized by only disconnecting the input of the effects in a loop while still mixing their output with the signal path, so a delay or reverb tail keeps ringing out after the loop is switched off.
What kind of MIDI connection does the HYDRA4X use?
It uses MIDI TRS Type A per the official MIDI specification, on a 1/8 inch (3.5 mm) stereo jack plug. Oscillator Devices notes it is compatible with Morningstar MIDI TRS connections and with all MIDI 1.0 compliant controllers.
How fast does the HYDRA4X switch after a MIDI command?
The maker states the time between sending a MIDI command and the switch matrix being fully set is a maximum of 15ms, fast enough that switching is effectively instantaneous in a live preset change.
How many presets does the HYDRA4X store?
Settings can be saved to one of 127 presets, each tied to a MIDI program change message. Saving is done by setting everything up with the buttons on top, then pressing and holding the white button and sending a PC message.
Are the HYDRA4X loops mono or stereo?
The four loops are mono. They can be reordered freely and run in parallel with each other or with the clean signal, with the one restriction that parallel loops have to be consecutive.
Sources (4)
- HYDRA4X - MIDI Loop Switcher - Oscillator Devices, Oscillator Devices
- HYDRA - MIDI Loop Switcher - Oscillator Devices, Oscillator Devices, 2026-09-08
- HYDRA4X - MIDI Loop Switcher - Oscillator Devices, Oscillator Devices
- Firmware Updates, Oscillator Devices
