Teenage Engineering has delivered substantial new firmware for its EP sampler family, with OS 2.5 arriving for the EP–133 K.O. II and EP–40 Riddim, alongside OS 1.5 for the EP–1320 Medieval. USB audio, sample reversing, longer mono recording, equal-length chopping, arpeggiation and a long list of sequencing and MIDI improvements make this a genuinely useful update cycle for the whole EP crew.
Key Features
- USB audio input and output turn the EP-133 and EP-40 into class-compliant stereo audio interfaces for phones, computers and DAWs.
- Sample reverse, adjustable recording sample rates and up to 40 seconds of mono sampling expand the sound-design side of both machines.
- Equal-length auto chop and a new Keys-mode arpeggiator make sample flipping and melodic performance more immediate.
- EP-1320 Medieval OS 1.5 has not been forgotten, joins the update cycle with USB audio ins and outs.
OS 2.5 gives the EP-133 K.O. II and EP-40 Riddim a sizeable set of new creative tools, while the EP–1320 Medieval continues its own quixotic journey with OS 1.5. This is not merely a quiet maintenance release; it gives these compact samplers a few new reasons to be pulled back into the middle of a session.
USB Audio Makes the EP Series Easier to Drop Into a Setup
The biggest practical addition for the EP-133 K.O. II and EP-40 Riddim is class-compliant USB audio. Connect either unit to a phone or computer and it can send and receive stereo audio without needing a headphone output or a separate audio interface.
That means the EP-133 can now sample directly from a computer, work as an audio source in a DAW, or record its own output straight into a session. The EP-40 gets the same treatment, which feels especially useful for producers using it as a performance-focused dub machine. Plug it into a laptop, route audio in, mangle it through the Riddim workflow, then print the result back into your project.
For small desktop rigs, travel setups and musicians who regularly make music away from a full studio, this is the sort of feature that quietly removes a pile of cables from the equation.
More Ways to Twist a Sample
Both OS 2.5 updates introduce sample reverse, a feature that can make a familiar library feel less familiar very quickly. Reverse a vocal fragment, cymbal swell, guitar chord or breakbeat and it becomes an instant transition, texture or slightly unsettling rhythmic detail.
The update also adds selectable recording sample rates: lo at 26.25 kHz, mid at 32 kHz and hi at the standard 46.875 kHz. The lower options give users a way to deliberately trade fidelity for character and storage efficiency, which feels entirely appropriate on a sampler designed for quick, tactile experimentation. Imported samples can still arrive at other sample rates via the EP Sample Tool.
Mono recording time has also doubled from 20 to 40 seconds. It is a modest number on paper, but it opens room for longer phrases, field recordings, spoken-word passages, guitar loops and less frantic sampling decisions. There is also equal-length auto chop, which divides a sample into evenly sized slices, handy for chopping a vocal phrase or getting a drum break onto the pads without manually placing every chop.
A Better Sequencer for People Who Actually Finish Patterns
The EP series has always been quick to sketch on, but OS 2.5 adds a few details that should make it easier to refine a pattern without starting over. Per-pad pattern copy and paste allows users to move a single track’s notes between patterns, while per-pad time shift moves every note on that track by a tick for small timing adjustments. It is the kind of sequencing control that can make a rigid loop sit a little more naturally without turning the workflow into a spreadsheet.
Fader automation can now be erased per track, and latched resampling allows users to hold FX and perform the X/Y effect controls live while resampling. Add improved time-stretching, permanent trimming to a sample’s trim points, playback-position display and a list of stability fixes, and both EP-133 and EP-40 feel more capable in the practical, everyday parts of music production.
Keys mode also gains an arpeggiator, activated by holding Timing and pressing multiple pads when using one-shot or legato sounds. New Blues, Harmonic Minor and Melodic Minor scales join the scale options, while scale and key settings are now saved per project. That should be welcome for anyone using the EP-133 or EP-40 as a compact melodic sketchpad rather than strictly a drum machine.
EP-1320 Medieval Joins the Firmware Party
The EP–1320 Medieval receives OS 1.5, continuing Teenage Engineering’s support for its most gloriously peculiar sampler. The Medieval remains a machine built for lutes, chants, bells, clattering percussion and beats that sound like they have been assembled in a tavern after midnight.
While the EP-133 and EP-40 updates lean heavily into new audio and sequencing functionality, the EP-1320 update keeps the wider EP platform moving forward and gives Medieval users another reason to revisit their projects. It is a good reminder that Teenage Engineering has treated the EP range as a living ecosystem rather than a one-and-done hardware release.
The full update notes and installation instructions are available through Teenage Engineering’s EP–133 guide, EP–40 guide and EP–1320 guide. If your EP has been sitting between sessions with an unfinished loop still loaded, OS 2.5 or 1.5 may be the right excuse to hit play again.
