Tag Archives: Yamaha Reface DX

Yamaha CE20 FM synthesizer (RIP?)

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I took a whack at repairing my 1982 Yamaha CE20 FM synthesizer. No joy, I’m afraid. I didn’t spot any obviously bad (fried) components, e.g., leaking electrolytic capacitors. I re-seated two fuses on the main logic (DM) board. Nope.

Well, the next step is to test the output voltage from the three voltage regulators. Fortunately, the regulator leads are exposed and I won’t need to disassemble the DM and symphonic modulator (SA) boards, again.

The CE20 service manual sadly lacks circuit schematics or a concept of operation. A few LEDs light up, but I don’t hear the familiar click of the muting relay. I wish Yamaha had published a schematic or start-up flow-chart. That information would assist signal tracing and diagnosis.

If I can’t find anything easy to fix, I’ll have to give the CE20 a proper burial. 🙂 The Yamaha Reface DX beats the old CE20 in many ways except for the CE20’s aftertouch keyboard, which was a real pleasure to play. Here’s how the CE20 and Reface DX FM implementations stack up:

                         CE20        Reface DX
                     ------------  ------------  
    Keys             49 full size  37 mini keys
    Key response      Vel sense     Vel sense
                      Aftertouch
    Polyphony
        POLY voices       8             8
        MONO voices       1             1
    Patches
        POLY voices       6          32 total
        MONO voices      14
    Ops per voice         2             4
    Effects               1             7
    Display              No            Yes
    Programmable         No            Yes
    MIDI                Nope           Yes
    Pedals           Exp, Sustain    Sustain
    Speakers             No          2 x 3cm
    Battery power        No            Yes

The CE20 voices are preset-only and cannot be reprogrammed. The Reface DX, on the other hand, has a spiffy user interface and 32 patch locations.

Even mentioning MIDI is a bit of a joke (1982!) and USB wasn’t born yet. Aside from the technical challenge, it’s hardly worth the repair. I ain’t gonna spend money on it…

I took pictures of the main DM board and the SA symphonic modulator board. Enjoy! No surface-mount devices inside. The SA board has the muting relay, BTW, in the upper right corner of the picture. Enjoy the view!

Yamaha CE20 main logic (DM) board

Yamaha CE20 symphonic modulator (SA) board

Copyright © 2025 Paul J. Drongowski

Reface DX acoustic instruments for ya

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One of my long-term projects is to collect and prepare acoustic instrument voices for Yamaha Reface DX. There aren’t as many high-quality acoustic voices as there are tons of bleeps and bloops. Most people associate FM synthesis with aggressive EDM sounds, but even 4-op FM is capable of so much more!

The project has come along pretty well. I’m now in the programming and tweaking phase to see if I can do better. However, the initial set of voices ain’t bad. Here is a table showing the voices and bank layout:

Bank 1

    1-1 Rhodes    1-2 Wurlitzer    1-3 LegendEP   1-4 E. Organ 3
    1-5 P. Organ  1-6 LargePipes   1-7 Cathedral  1-8 GentlePipe

Bank 2

    2-1 WarmPad    2-2 Wash3Strng  2-3 Wood+Horn   2-4 Woodwindy
    2-5 Warm&Cozy  2-6 RealStrngs  2-7 Horn 2 +1   2-8 FluteVoice

Bank 3

    3-1 HornSwell  3-2 SoftBrass   3-3 WoodEns. 4  3-4 Oboe 1 
    3-5 TrumpetMel 3-6 Trombone 2  3-7 Clarinet    3-8 Bassoon

Bank 4

    4-1 Wood EP    4-2 DynaString  4-3 Warm&Cozy   4-4 Violin -1
    4-5 WoodEnsFlt 4-6 Wash3Strng  4-7 HamB3       4-8 Real flute

The “+1” and “-1” are reminders to change the OCTAVE slider before playing. To do: Add and store transpose changes in the voice SysEx (SYX). Next version!

The first three banks are relatively stable. Bank four voices are experiments in progress, back-ups or patches that I don’t want to lose. To do: I need to collect and tweak a few solid Hammond-ish B-3 sounds.

I drew on multiple sources. Many voices come from Yamaha Soundmondo and the Reface DX Legacy Project. If you’re looking for raw material to start patches of your own, I recommend the converted YS200 voices at the Legacy Project.

The DX11 conversions seem to have a few issues, i.e., strings don’t sound like strings (even remotely). Fortunately, the YS200 and DX11 are based on the same synthesis engine (Yamaha YM2414). Go for the YS200 first.

Here is a link to a ZIP file with Reface DX acoustic instrument patches. Each voice is a separate SYX file, i.e., a file containing one or more MIDI System Exclusive dump messages. I use MIDI-OX to download patches to Reface DX. If I like a patch, I hit the Reface STORE button, choose a target voice slot, and confirm the store operation.

Have fun!

Interested in Reface DX? Here are a few more links:

Copyright © 2025 Paul J. Drongowski

Want vs. need: Yamaha Seqtrak

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It doesn’t cost anything to window shop!

With the holiday selling season in full swing, I took another look at Yamaha Seqtrak. Ya never know when a bargain might present itself, so it’s good to be ready. 🙂

Seqtrak is Yamaha’s low cost alternative to the all-in-one Teenage Engineering OP-1 — a battery-powered synthesizer, sampler and sequencer. The price is much sweeter, $399 USD (MAP/street), than Teenage Engineering.

I’ve been hesitant to chomp on Seqtrak because I don’t really need a groove box. Yeah, it might provide fun occasionally, but it doesn’t really fulfill a need for what I play live (mainly keyboard emulation of acoustic instruments).

A few postings on Yamaha Musicians Forum motivated me to investigate further, however. Seqtrak implements two forms of synthesis: AWM2 and FM. At first, the AWM2 support sounds like a yawner. Guess what? The AWM2 sound set is pretty much the Motif XF (MOXF) factory sounds! That ain’t chopped liver.

The Seqtrak DX FM implementation is the same as the Reface DX. Even though it’s a four-OP implementation, feedback is supported on any OP, yielding a harmonically richer sound than four-OP of yesteryear. Both DX FM and AWM2 synths can be routed into a robust collection of DSP effects, including rotary speaker, VCM effects and HD reverb.

I wish the Seqtrak DX FM editor supported the Reface DX. It is one nice editor.

Thus, $399 buys a three channel (two synth, one DX FM) battery-powered MIDI module supporting DX FM and Motif XF synthesis. That’s quite a bargain when Reface DX alone costs $400 or so on a typical day.

As an expander, my main quibble is usage model. Seqtrak does not have a display showing the currently selected voice. I can’t tolerate that level of uncertainty during a live performance. The Seqtrak app controls all, but it means schlepping another piece (iPad) to the gig and making everything work live.

Still, it’s enticing. A case of want over need.

Seqtrak inside

What’s inside that tiny box? Thanks to a brave soul on LoopyPro, we get the picture.

Seqtrak consists of three printed circuit boards (PCB): a front panel board which runs most of the length of the chassis, a large digital electronics board mounted in parallel with the front panel board, and a small analog electronics board near the battery and speaker. The analog electronics board has connectors for USB-C, PHONES, AUDIO IN and MIDI.

SeqTrak printed circuit boards

The main event is the digital electronics board, usually called “DM” in Yamaha-speak. In this picture, we are looking at the bottom of the board. The top of the board — sometimes called the “component side” — is obviously out of view. The three large rectangular integrated circuits (IC) are SDRAM (e.g., Winbond W9825G6KH-6 256Mbit Parallel 166 MHz, typically organized as 32MBytes). The specially labelled IC is (likely) a Winbond 256Mbit (32MByte) NOR flash ROM containing the Seqtrak code.

The memory ICs surround the foil pattern for a Yamaha proprietary SWX processor. I’m guessing SWX09 or SWX10. SWX combines an ARM core with AWM2 tone generation and DSP effect processors. Seqtrak implements DX FM because only SWP70 implements FM-X. Low cost devices like Seqtrak usually employ a single, highly integrated SWX and do not include a separate SWP70 tone generator.

There may be additional memory devices on the component side of the DM board. The battery is a 3.6V 2100mAh Li-ion battery.

Copyright © 2024 Paul J. Drongowski

Yamaha Reface DX in the house

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UPS surprised me and delivered Yamaha Reface DX one day early. Hurray!

As I’ve mentioned before, I owned and played a Yamaha DX21 back in the late 80s and early 90s. (The 4-op, FM DX21 was released in 1985.) The DX21 was the first synth that I took to church. I remember playing string, brass and organ patches.

After I unboxed the Reface DX, my head was spinning. Did Rock Moranis’s mad-scientist dad hit my old DX21 with a shrinking ray? The styling and feel is so DX21 that it was a definite case of déjà vu.

The Reface DX has the same solid feel and build as my well-worn Reface YC. I bought Reface YC in 2017 and I’ve played the snot out of it. I take care of my tools and the Reface YC has held up pretty well. I expect the same from Reface DX.

One difference tho’, the Reface YC keys have become clacky (for lack of a better term). Playing the new Reface DX reminds me of how smooth the YC felt at first. The DX velocity response is nice. The DX is still three octaves, so my major complaint about mini-keyboards remains valid. The Reface HQ mini-keys have a more substantial feel than the Yamaha PSS-A50.

After turning this bugger on and playing — Wow, this is a real instrument, a real synthesizer. The DX stores patches unlike its Reface brethren. I went through the presets and found roughly 20 keepers. I’m not into aggressive so patches like “Wobble Bass” got the ax. I made a chart and took note of target memory locations.

Sound-wise, it’s a very nice 4-op implementation. Eight note polyphony is enough to be dangerous. In comparison, Modal Skukpt SE is four voice polyphonic and I always get frustrated when the fifth note causes note theft. I’m putting the Reface DX through a Yamaha Stagepas100 and it sounds great. The built-in speakers are the same old “courtesy speakers” and aren’t meant for serious use.

The effects section is strong. Reface DX implements two post effects in series. The workflow is simple and direct: Hit the EFFECT button and use the data entry strips/switches to make your choices. There is a lot you can do through effects alone without getting into FM programming.

You all might say, “Late to the party, PJ.” However, I made a conscious decision in 2017 to buy one Reface and the YC filled most of my needs. With YC, it’s organ or nothing and that has always felt limiting. Reface DX is a true synth and covers a lot of sonic territory. Maybe I would have been happier with Reface DX from the start? It just doesn’t matter…

Yamaha Soundmondo

Being late has one advantage, Yamaha’s Soundmondo patch-sharing site is full to the brim with Reface DX programs. I decided to start with Manny Fernandez’s patches — go pro. I honestly don’t have time to wade through a lot of, well, crap.

Speaking of which, there are so many DX programs that Yamaha’s tagging scheme is not sufficient to efficiently filter out irrelevant dreck. People can tick off as many tags as they like — inappropriately so. Worse, Soundmondo game-ified contributions, encouraging people to use more tags than necessary in order to win more ears and likes. These factors make efficient search impossible. Yamaha should limit the number of tags per sound to three, max.

Beyond those negatives, Soundmondo works like a charm with Reface DX. I never used Soundmondo with the YC since pulling drawbars is so natural and immediate. With Soundmondo, I quickly found useable string and brass patches. The workflow is smooth and it’s easy to store a new voice on the DX as long as you know which memory locations to sacrifice. No problem.

My only remaining quibble with Soundmondo is, again, due to scale. Soundmondo uses the scrolling reveal approach to search results and does not return to the last selected result. That means you have to re-scroll through search results all the way from the beginning! Since people over-tagged their entries, that makes for a lot of dreck to scan through over and over again. Tedious.

Quick summary

So, Reface DX is now on sale for $250 USD (MAP). I stayed good to my word and waited for close-out pricing before buying a second Reface. If you can find a Reface DX for $250, buy it. You won’t regret the decision.

What’s next? I’m going to try loading converted DX21 patches from the Reface DX Legacy Project. Soundmondo is a little short on FM woodwinds and I’m going to give the old DX21 sounds another shot at glory.

Copyright © 2024 Paul J. Drongowski

Reface DX: No static at all

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If you’ve browsed Yamaha Reface at on-line retailers, you’ll know that Reface DX and Reface CS are currently on sale. The DX and CS are the two Katzenhammer kids which share the same internal design, using a Yamaha-proprietary SSP-2 processor as the central compute engine.

The Reface DX price is startling: $250 USD (MAP). Wow! That’s the price of a mid-range guitar pedal. Makes me wonder if the DX and CS are being closed out or if Mark 2 models are in the works. The venerable SSP-2 is supplanted by the SSP-3 and perhaps the inventory of SSP-2 is depleted.

The Reface CP and Reface YC MAP prices remain the same. I suspect that sales of these models remain solid as there always seems to be a need for good EP and organ sounds.

That DX price is a clearance price. When Reface was released, I vowed to buy at blow-out pricing. Yep, I put a Reface DX on order.

A few Reface DX programming links

First off, I’m amazed at the number of contributed DX patches at Yamaha’s Soundmondo sharing site. There are literally thousands of Reface DX patches. The Soundmondo tagging idea is good, but too many punters over-tagged their submissions. I’m looking for “orchestral” sounds and there are many tagged patches that are not remotely “orchestral”. A search system is only as good as the quality of its tagging.

If that’s not enough patches for you, try the Reface DX Legacy Project. Martin Tarenskeen maintains this vast library of Reface DX patches converted from old FM machines. I can’t vouch for the quality of the conversions (yet), but I’ll be heading there for old 4-op DX21 patches. I had a DX21 back in the day, and know the factory sound set quite well. I still have the original cassette tape with DX21 patches on it!

I also plan to do a little FM programming. This series of articles by Manny Fernandez is excellent:

Learn from the best in the field — that would be Manny. His articles have links to his example patches in the Soundmondo library.

You’ll need a Reface DX algorithms and envelope cheat-sheet (PDF), too.

Reface DX is old enough to be a grown up by now. So, there’s plenty of on-line support if you choose to jump into the Reface DX pool.

Yamaha SEQTRAK FM

I was curious to see how SEQTRAK FM stacks up against Reface DX. My conclusion — it’s the same FM engine:

  • 4-op, 12 algorithms, polyphony 8
  • Same algorithms and parameters
  • SEQTRAK includes many Reface DX patches

Looking beyond FM, SEQTRAK does AWM2, sampling and sequencing, and offers more effects. I’m more of a player than a button-pusher, so Reface DX is better for my personal needs.

Reflecting on the SEQTRAK FM and AWM2, I would expect to find a Yamaha proprietary SWX09 at its heart. The SWX09 core executes the Renesas SH architecture, same as SSP. Plus, SWX09 has an integrated AWM2 tone generation engine.

Copyright © 2024 Paul J. Drongowski