I’m always in the mood for tiny noise makers and, possibly, mods. My latest fantasy is a good-sounding add-on module to be controlled by a Novation Launchkey 49 Mk4 or Arturia Keylab Essential 49 (both in my clutches).

So, round up the usual suspects! I thought about taking the Mototool to the Yamaha PSS-A50 since it has good mod potential. I’d like to keep the main board and front panel intact, ditching the mini-keyboard, After listening to the A50 sounds, I got cold feet! If I did go Dr. Frankenstein on it, the front panel plus main board combo would be larger than my goal.

I browsed through a zillion Yamaha and Casio service manuals and teardown videos. The now discontinued PSS series keyboards are the smallest having only two internal PCBs. The PSR-F50+ relatives have as many as five PCBs. Even the simplest looking Casios (e.g., CT-S1, CT-S100) have three boards or more. Nope.

Pocket Miku, AKA NSX-39, is a good candidate although one must be willing to sacrifice MIDI channel 1 to that atrocious Miku voice. I did a little deep diving on Japanese NSX sites and found a Real Acoustic Sound (RAS) sax demo that is every bit as good as an Articulated Element Modeling voice on Tyros. It’s a shame that Yamaha never pursued the RAS tech. NSX is pretty much dead to Yamaha, too, because every NSX link to a Yamaha site is a 404.

I A/B tested PSS-A50 voices against NSX-39. Same waveforms, I’m sure. The NSX-1 chip (YMW820) is a kissing cousin to the Yamaha SWLL (YMW830) in the now defunct PSS series. The NSX-1 has better effects, a full GM sound set, and a more capable XG implementation. Goes to show that Yamaha could be making a killer E-series machine, but chooses to make dumb marketing decisions.

The main drawbacks to either A50 or NSX-39 is MIDI communication. Both devices would require a 5-pin MIDI hack or a MIDI host.

SAM, where are you?

I also compared Dream SAM against the Yamaha SWLs. Specifically, I A/B’ed the Yamaha sounds against the MIDIPLUS miniEngine USB. The miniEngine combines a USB MIDI host, 2,500mAh rechargeable battery, and Dream SAM2553 synthesizer chip.

I honestly want to like the miniEngine, however, a few of its flaws are hard to overlook: serial (5-pin) MIDI doesn’t work, the audio output is a bit noisy and the SAM2553 sound doesn’t quite rise to Yamaha. The SAM has a nice Roland GS implementation, providing access to certain high-want parameters via MIDI CC and NRPN messages. Yamaha XG requires SysEx to access key parameters like REVERB type and CHORUS type, effectively putting those parameters out of the reach of most MIDI controllers (including mine).

Still, I can’t quit SAM. M5Stack sell the U187 MIDI unit for $14.50 USD. The U187 is tiny, has two 5-pin MIDI DIN connectors and is based on the SAM2695. After I threw in GROVE connectors, etc. and an M5Stack buck converter, the dust settled around $60 including tax, tariff and shipping. I’ll let you know how it goes.

CME H2MIDI Pro

And, speaking of MIDI hosts. I tried driving the A50 and NSX-39 through a DoReMiDi USB MIDI HOST UMH-20 from Yamaha MODX6. No Joy. I think the Active Sensing messages from the MODX make the DoReMiDi crazy and message transmission was sporadic.

I’ve had issues with the UMH-20 before. At this juncture, I cannot recommend the DoReMiDi.

I ordered and tried the CME H2MIDI Pro instead. No issues. CME know how to make MIDI devices! Plus, the H2MIDI can be configured to filter out Active Sensing, an important feature because Yamaha refuses to provide a software switch that turns off Active Sensing (despite many customer requests).

CME is a strong recommend.

SWLL update

A few intrepid investigators are deep-diving the Yamaha SWLL (and related) processors. The SWL processors are used extensively in the entry-level E-series keyboards. The SWLL is a super-low cost system on a chip which combines an AWM tone generator and an ARM7TDMI core.

In previous posts, I’ve danced around the specific host core in the SWL series. We now know, conclusively, it’s an ARM7TDMI core. Yamaha has been phasing out the old SH architecture cores in favor of ARM (and Linux). BTW, the CSP-100 series may be the last product based on SH. The CLP-800 employs the newest member of the SWX family, the SWX-100F. No doubt, it’s an ARM, too. CVP, on the other hand, is RIP.

Copyright © 2025 Paul J. Drongowski