Discovering PO-33 Scale

Pocket Operator PO-33 K.O. is a great portable sampler, which gives you lots of possibilities in the one handheld device. But despite having very informative documentation it lacks some details regarding what scale is used in there. So let’s discover that by ourselves!

Right from first seconds of playing with PO-33, anyone can hear that keys 1-8 and 9-16 sound like some basic scale. Indeed, it’s minor. If we check how the sample is being transposed through pocket operator keys range we will see the repeating layout in 2 octaves – 1-8 and 9-16:

+7+8+10+11
0+2+3+5
-5-4-2-1
-12-10-9-7

From those notes we can play natural minor (0, +2, +3, +5, +7, +8, +10):

A natural minor

or harmonic minor by raising 7th note by one semitone (0, +2, +3, +5, +7, +8, +11) :

A harmonic minor

So you can play natural minor or harmonic minor by alternating between last two keys of octave in PO-33 (keys 3/4 and 15/16).

But what if we also want to play in major scale on same device? No worries, it’s still possible once you transpose your sample.

One of the first pieces of information in musical theory that I’ve learned was – C major and A minor scales reuse same notes (all white piano keys), the only difference is the root note: C major starts from C, and A minor starts from A. So while having PO-33 in A minor scale (by recording a sample in A) we still can play C major by starting scale not from 5 or 13, but from 3rd note in initial scale (+3 semitones) which corresponds to pocket operator’s keys 7 or 15. 

Therefore we can easily come up with magical formula for major scale in PO-33: 

  • transpose your sample to <major root> – 3 semitones
  • record sample
  • play scale having root at buttons 7 or 15 instead of 5 or 13

Sounds good…. BUT!

The main killer-feature of pocket operator is portability, and adding such restriction as “transpose sample before recording it into PO-33” makes it impossible to use such approach ‘in the field’ when you are not recording samples from your DAW or other software which allows to edit samples prior to recording.

Luckily PO-33 has built-in function to change pitch of the sample. Once recorded, you can transpose sample by turning left knob when TONE mode is selected with FX button. Just drop sample pitch 3 semitones lower than planned scale root and you’re good to go!

Unfortunately, PO-33 doesn’t show you exact amount of semitones being shifted, but rather ‘progress-bar’ representation. Therefore be careful counting semitones while turning knob 🙂

For instance, if you have sample in root key of future major scale – you would need to shift it 3 semitones down, which corresponds to 6 ‘tick marks’ in pitch shifting mode: 

-3 semitones is shown as (base – 5 tick marks)

As a result magical formula for major scale on Pocket Operator PO-33 looks as follows:

  • record sample in any key 
  • pitch it to <major scale root> – 3 semitones
  • play scale having root at buttons 7 or 15 instead of 5 or 13

Hope you’ve found it useful!

For additional reference of exact notes on all PO-33 keys I’ve implemented small web app:


PO-33 Scale App

Shows note mapping of PO-33 keys in scale based on sample pitch.

  • To change key of input sample – click on current sample key for dropdown to appear.
  • Two sliders allow to change current scale from minor to major and from natural to harmonic.
  • Highlighted PO-33 keys correspond to scale’s root note.
  • Selected PO-33 key will also be highlighted on piano roll.
Sample:

2 thoughts on “Discovering PO-33 Scale”

  1. Thank you for posting this. I am not well versed in musical theory, know about scales and keys, but aren’t very good at transposing. This really helped me understand what I need to do to get the progressions I want out of my PO 33.

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