I got my hands on an OP-Z Music Synthesizer and am amazed at how fun it is to make music! It’s a worthy companion to one of my all-time-favorite consumer products, the OP-1.

I had questions about what’s inside, so we did what true hackers do – break out a T4 torx wrench!!

The unit is incredibly small – very portable and only 10mm thick:

The back (not shown) is easily removed by rotating the feet so that the rear panel comes off. Inside is a user-replaceable battery. A little surprise is that the expansion slot contains a phone holder that can be attached to the back of the unit — thoughtful design!

The battery and dummy expansion-slot holder can be removed:

Under the battery is a little easter egg based on the plaque that flew on the Pioneer spacecraft:

Here’s the expansion slot. There is a small gap between this and the battery area; perhaps an extra battery can be connected here.

I probed the pads, but didn’t find much interesting. I found two ground pads (connected to the negative side of the battery), and two pads that looked like they should provide power to the module … but they didn’t seem to be providing any power (even when I turned on the sequencer and had enabled the expansion port). The other pads didn’t have any voltage on them, except for one that was 1.8v.

So, I couldn’t draw any conclusions about what modules we might expect in the future.

The top half of the case contains all the keyboard buttons, keyboard LEDs, and the knobs for the rotary encoders.

I was thinking of trying to remake this part in sturdier aluminum, but the keyboard is an integral part – the plastic is melted in over 20 places, and it would be complicated to duplicate this. It does explain why the keyboard feels so rigid, though! This makes repair of individual keys difficult – the whole top would probably be replaced as a unit. I pressed on the bearings from the backside and they were firmly in place.

The ribbon cable that goes to the yellow power and volume knob came a little squished in my unit. You can also see (at the bottom) how the melted plastic of the case holds down the board – I wish these were tiny screws, but it would probably make the whole unit thicker:

This switch does have a connector, though, so it is replaceable without replacing the whole front cover. It also looks like it’s possible to replace the yellow knob, too, should that break.

The encoders are pretty cool. They are basically magnets housed in ball bearings … they should last just about forever! Note that the multicolor lights come from the keyboard flex circuit.

Here’s the main module inside the case. It connects to the upper half via a single ribbon cable.

The USB-C connector and the headphone jack are both on flex cables so they won’t break if tugged at. If they break, they’ll have to be replaced, along with the main flex circuit running between the left half and right half of the unit. There is more of the power board hidden under this flex, along with a solid ground to the keyboard for protection from static electricity.

At the left and right we have ICs for the magnetic encoders. These are IC Haus model TW11, which are low power and measure 10 bits (meaning that they can read 1024 different angles around a circle).

At the center is a bluetooth antenna and a Nordic Semiconductor NRF52832 Bluetooth Low Energy SoC.

The DSP board dissipates the most power. This board is revision 5:

The main components are:

Processor: Analog Devices model ADSP-BF703 – Low Power 400MHz Blackfin+ with 256KByte SRAM

DRAM memory: Micron MT47H64M16NF-25E – 64MB, DDR2-800, x16 width

FLASH memory: Micron FBGA code NW228, unknown part number and unknown size. It may be similar to code NW225.

Lastly, we can see the microphone and dual-color LED on a flex board wrapped around the end of the unit.

If you find yourself in Boulder, CO, come visit our hackerspace! We’ve got a bunch of people interested in building our own synthesizers, reverse engineering, and making music!