A Yamaha DX7 On A USB Dongle

November 24, 2023 by Lewin Day 24 Comments

The Yamaha DX7 was released in 1983, with its FM synthesis engine completely revolutionizing the electronic music world at the time. It didn’t come cheap, and still doesn’t today, but we are blessed with emulators that can give us the same sound on a budget. In that vein, [Kevin] decided to whip up a Yamaha DX7 you can carry around in a little USB dongle.

The build centers around the use of a Raspberry Pi Zero, Zero W, or Zero 2W configured to run the MiniDEXED DX7 emulator. The Pi is then set up with a dongle adapter board that allows it to run in USB Gadget mode. The Zero line of Raspberry Pis are perfect for this use, as they draw less current and so can, under the right conditions, run off a computer’s USB port. The Pi receives MIDI commands over the USB interface, and outputs sound via a Pimoroni Audio Shim. Effectively, the result is a single-channel DX7 synth that plugs in via USB; or eight channels if you use the more powerful Zero 2W.

[Kevin] readily admits that there probably isn’t much use for a DX7 dongle, given that you could just load a DX7 emulator in your DAW of choice instead. Regardless, it’s a fun build, and one that ably demonstrates the USB Gadget mode of operation for the Raspberry Pi. Video after the break. Continue reading “A Yamaha DX7 On A USB Dongle” →

Bare Metal Gives This Pi Some Classic Synths

April 19, 2022 by Jenny List 18 Comments

We’re used to seeing the Raspberry Pi crop up in a wide range of the projects we show you here, but it’s fair to say that they usually feature some sort of operating system. There’s another way to use a Pi, more akin to using a microcontroller such as the Arduino: by programming it directly, so-called bare-metal programming. MiniDexed is an example, and it copies a classic Yamaha professional synthesiser of the 1980s, by emulating the equivalent of eight of the company’s famous DX7 synthesisers in one unit. It takes almost any Pi, and with the addition of an audio board, a rotary encoder, and an LCD display, makes a ready-to-go unit. Below the break is a video of it in operation.

It’s fair to say that we’re not experts in Raspberry Pi bare metal programming, but it’s worth a diversion into the world of 1980s synthesisers to explore the DX7. This instrument was a staple of popular music throughout the 1980s and was a major commercial success for Yamaha as an affordable FM synthesiser. This was a process patented at Stanford University in the 1970s and subsequently licensed by the company, unlike other synths of the day it generated sound entirely digitally. It’s difficult to overestimate the influence of the DX7 as its sound can be heard everywhere, and it’s not impossible that you own a Yamaha FM synth even today if you have in your possession a sound card.

Curious about the DX7? Master chip-reverse-engineer [Ken Shirriff] exposed its secrets late last year.

Continue reading “Bare Metal Gives This Pi Some Classic Synths” →

Ken Shirriff Breaks Open The Yamaha DX7

November 25, 2021 by Bryan Cockfield 23 Comments

For better or worse, this synthesizer was king in the 1980s music scene. Sure, there had been synthesizers before, but none acheived the sudden popularity of Yamaha’s DX7. “Take on Me?” “Highway to the Dangerzone”? That harmonica solo in “What’s Love Got to Do With It?” All DX7. This synth was everywhere in pop music at the time, and now we can all get some insight from taking a look at this de-capped chip from [Ken Shirriff].

To be clear, by “look” that’s exactly what we mean in this case, as [Ken] is reverse-engineering the YM21280 — the waveform generator of the DX7 — from photos. He took around 100 photos of the de-capped chip with a microscope, composited them, and then analyzed them painstakingly. The detail in his report is remarkable as he is able to show individual logic gates thanks to his powerful microscope. From there he can show exactly how the chip works down to each individual adder and array of memory.

[Ken]’s hope is that this work improves the understanding of the Yamaha DX7 chips enough to build more accurate emulators. Yamaha stopped producing the synthesizer in 1989 but its ubiquity makes it a popular, if niche, platform for music even today. Of course you don’t need a synthesizer to make excellent music. The next pop culture trend, grunge, essentially was a rebellion to the 80s explosion of synths and neon colors and we’ve seen some unique ways of exploring this era of music as well.

Thanks to [Folkert] for the tip!

Synthesizer Gets An External Touch Screen

July 8, 2020 by Tom Nardi 3 Comments

Like other owners of the high-end Yamaha MODX, [sn00zerman] wasn’t happy with the synthesizer’s integrated touch screen. It’s a bit small, and not at a very good angle for viewing. So he made it his mission to find some way of adding a larger external touch screen without making any permanent modifications to the expensive instrument.

This might seem like a tall order, but he wasn’t starting from zero. It was already known that you could plug an external display into it if you used a USB to DVI/HDMI adapter; but without the touch overlay it wasn’t a particularly useful trick. He pondered adding an external connector for the device’s built-in touch screen overlay, but that broke his no modifications rule. Considering how much one of these things cost, we can’t blame him for not wanting to put a hole in the side.

Sometimes you just have to dig out the right parts.

So he started to look for a software solution to get him the rest of the way. Luckily the MODX runs Linux, and Yamaha has made good on their GPL responsibilities and released the source code for anyone who’s interested. While poking around, he figured out that the device uses tslib to talk to the touch screen, which [sn00zerman] had worked with on previous projects. He realized that the solution might be as simple as finding a USB touch screen controller that’s compatible with the version of tslib running on the MODX.

In the end, a trip through his parts bin uncovered a stand-alone touch screen controller that he knew from experience would work with the library. Sure enough, when plugged into the MODX, the OS accepted it as an input device. With the addition of a USB hub, he was able to combine this with an existing display and finally have a more comfortable user-interface for his synthesizer.

Now all he’s got to do is plug in a USB floppy drive, and he’ll have the ultimate Yamaha Beat Laboratory.

Continue reading “Synthesizer Gets An External Touch Screen” →

Quality Upgrades Give Old Synth New Lease On Life

May 13, 2020 by Lewin Day 13 Comments

Technology marches on at a rapid pace, but in many fields much love remains for older hardware. While still highly capable, there’s often room for improvement thanks to components made available in the intervening years. After longing for his SY-77 synthesiser of the 90s, [Mark] sourced a tired SY-99, the next model up in the line – and set to work on some upgrades.

The SY-99 relied on floppy disks for storage, but the mechanical drives are now difficult to maintain, to say nothing of the unreliability of floppy media. [Mark] installed a SD Card HXC floppy emulator instead, using a Sparkfun SD breakout to neatly install the card slot in the synth’s case. The tired LCD was replaced with a newer model using the same controller, with an LED backlight proving a nice upgrade over the original EL unit.

Additionally, [Mark] realised that there was scope to create his own upgrade modules with off-the-shelf SRAM chips. This proves far cheaper than sourcing second-hand Yamaha stock off eBay, and is readily achievable by anyone with a basic understanding of digital logic. The ICs can be had for a few dollars, versus well over $50 for the original cards – if you can even find them. Some labor is involved, but it’s a lot less painful to the wallet.

[Mark]’s work is a great example of how hardware that was once prohibitively expensive can be given greater functionality at a lower cost thanks to new technology. We’ve seen other synths modded too, like this Korg Monotron. If you’ve been tinkering away in a keyboard yourself, be sure to let us know!

[Thanks to CRJEEA] for the tip]

What To Know When Buying Chips That Haven’t Been Made For Three Decades

January 15, 2020 by Erin Pinheiro 29 Comments

Those of us who have worked with vintage sound generator chips such as the Yamaha FM synthesizers in recent years have likely run into our own fair share of “fake” or “remarked” chips, sometimes relabeled to appear as a chip different than the die inside the packaging entirely. [David Viens] from Plogue has finally released his findings on the matter after 3 years of research. (Video, embedded below.)

The first thing to determine is in what way are these chips “fake”? Clearly no new YM2612’s were manufactured by Yamaha in 2015, but that doesn’t mean that these are simply unlicensed clones put out by another die factory. [David] explains how these chips are often original specimens sourced from recycled electronic waste from mostly environmentally unsafe operations in China, which are then reconditioned and remarked to be passed as “new” by resellers. Thankfully, as of 2017, he explains that most of these operations are now being shut down and moved into an industrial park where the work can be done in a less polluting manner.

The next thing that [David] dives into is how these remarked chips can be spotted. He explains how to use telltale signs in the IC packaging to identify which chip plant produced them, and visible indications of a chip that has been de-soldered from a board and reconditioned. There are different ways in which the remarking can be done, and sometimes it’s possible to undo the black-top, as it’s called, and reveal the original markings underneath with the simple application of acetone with a cotton swab.

We’ve talked about fake chips and how they can lead to hardware failure here before, but in the case of chips like these which aren’t manufactured anymore, we’re not left with much choice other than FPGA or software reimplementations. Check out [David]’s 40-minute look into these chips after the break.

Continue reading “What To Know When Buying Chips That Haven’t Been Made For Three Decades” →

Repairdown: Disklavier DKC500RW Control Unit

June 3, 2019 by Tom Nardi 61 Comments

If you’ve been kind enough to accompany me on these regular hardware explorations, you’ve likely recognized a trend with regards to the gadgets that go under the knife. Generally speaking, the devices I take apart for your viewing pleasure come to us from the clearance rack of a big box retailer, the thrift store, or the always generous “AS-IS” section on eBay. There’s something of a cost-benefit analysis performed each time I pick up a piece of gear for dissection, and it probably won’t surprise you to find that the least expensive doggy in the window is usually the one that secures its fifteen minutes of Internet fame.

But this month I present to you, Good Reader, something a bit different. This time I’m not taking something apart just for the simple joy of seeing PCB laid bare. I’ve been given the task of repairing an expensive piece of antiquated oddball equipment because, quite frankly, nobody else wanted to do it. If we happen to find ourselves learning about its inner workings in the process, that’s just the cost of doing business with a Hackaday writer.

The situation as explained to me is that in the late 1990’s, my brother’s employer purchased a Yamaha Mark II XG “Baby Grand” piano for somewhere in the neighborhood of $20,000. This particular model was selected for its ability to play MIDI files from 3.5 inch floppy disks, complete with the rather ghostly effect of the keys moving by themselves. The idea was that you could set this piano up in your lobby with a floppy full of Barry Manilow’s greatest hits, and your establishment would instantly be dripping with automated class.

Unfortunately, about a month or so back, the piano’s Disklavier DKC500RW control unit stopped reading disks. The piano itself still worked, but now required a human to do the playing. Calls were made, but as you might expect, most repair centers politely declined around the time they heard the word “floppy” and anyone who stayed on the line quoted a price that simply wasn’t economical.

Before they resorted to hiring a pianist, perhaps a rare example of a human taking a robot’s job, my brother asked if he could remove the control unit and see if I could make any sense of it. So with that, let’s dig into this vintage piece of musical equipment and see what a five figure price tag got you at the turn of the millennium.

Continue reading “Repairdown: Disklavier DKC500RW Control Unit” →