We’re big fans of the Zynq, which is an answer to the question: what do you get when you cross a big ARM processor with a big FPGA? So it isn’t surprising that [GregTaylor’s] project to emulate the OPL3 FM Synthesis chip in an FPGA using the Zynq caught our eye.
The OPL3 (also known as the Yamaha YMF262) was a very common MIDI chip on older PC sound cards. If you had a Sound Blaster Pro or 16 board, you had an OPL3 chip in your PC. The OPL3 was responsible for a lot of the music you associate with vintage video games like Doom. [Greg] not only duplicated the chip’s functions, but also ported imfplay from DOS to run on the Zynq’s ARM processors so he could reproduce those old video game sounds.
The Zybo board that [Greg] uses includes an Analog Devices SSM2603 audio codec with dual 24-bit DACs and 256X oversampling. However, the interface to the codec is isolated in the code, so it ought to be possible to port the design to other hardware without much trouble.
To better match the original device’s sampling rate with the faster CODEC, this design runs at a slightly slower frequency than the OPL3, but thanks to the efficient FPGA logic, the new device can easily keep up with the 49.7 kHz sample rate.
Using an FPGA to emulate an OPL3 might seem to be overkill, but we’ve seen worse. If you prefer to do your synthesis old school, you can probably get a bulk price on 555 chips.
Continue reading “Zynq and the OPL3 Music Synthesizer”
The bike above may look like a pristine Yamaha prototype, but it’s actually the work of [Julian Farnam], a motorcycle hacker of the highest level. We caught his Yamaha A-N-D FFE 350 on OddBike, and you can read [Julian’s] own description of the bike on his Slideshare link.
The FFE 350 started life as a Yamaha 1990’s RZ350 two-stroke racer. From there, [Julian] gave it his own Forkless Front End (FFE) treatment. Gone is the front fork, which while common in motorcycle and bicycle design, has some problems. Fore-aft flex is one – two thin tubes will never make for a rigid front end. Changing geometry is another issue. Since forks are angled forward, the front wheel moves up and to the rear as the shocks compress. This changes the motorcycle’s trail, as well.
Forkless designs may not have these issues, but they bring in a set of their own. A forkless design must have linkages and bellcranks which are often the source of slop and vibration. [Julian’s] design uses two sets of linkages in tension. The tension between the two linkages removes most of the slop and provides that directly connected feel riders associate with forks.
The FFE 350 wasn’t just a garage queen either – it laid down some serious laps at local tracks in Southern California. Unfortunately, the forkless design was too radical to catch on as a commercial venture, and the FFE has spent the last few years in storage. [Julian] is hard at work bringing it back to its 1998 glory, as can be seen on his restoration thread over on the Custom Fighters forum.
Check out this brand new Yamaha keyboard. The fact that we’re seeing the guts means that [Todd Harrison] can kiss his warranty goodbye. But by now you should know that he doesn’t look to others when something goes wrong with his electronics. This time around he’s not repairing anything. He didn’t like having to plug in headphones on the rear of the keyboard. He cracked it open and relocated the headphone jack to a more convenient location.
As you can see, there’s a ton of room inside once the MDF base which holds the speakers and some sounding boxes has been removed. While he’s in there he takes a good look at the mechanics of the keys. They’re weighted with metal rods (seen above) to help the electronic instrument feel more like an acoustic version to the player. But he doesn’t neglect the chance to gawk at all the electronics as well.
After pulling out the PCB that has the headphone jack on it he goes to work with a solder sucker. With the solder gone he cuts through the glue that holds the jack on the board. All that’s left is to solder some wire in its place and give it a nice project box as an enclosure. To complete the hack he mounts the box on the MDF base and now the headphones connect on the front. See the entire process in the video after the break.
Continue reading “Put that headphone jack anywhere you want it”
Electronic musical instruments are a lot of fun for a hacker because, with a small palette of tools, know-how and curiosity, they are easily modified. As with any hack, there is always the chance that the subject will be ruined, so it’s not necessarily worth the risk to muck about inside your thousand-dollar pro synthesizer. Luckily for all of us, there are shovel-fulls of old electronic musical toys littering the curbs and second-hand shops of the world. These fun little devices provide ample opportunity to get familiar with audio electronics and circuit bending techniques.
A note on definitions: the term “circuit bending” can be synonymous with “hardware hacking” in the world of audio electronics, and we have seen some debate as to which term is better suited to a given project. We welcome you to share your viewpoints in the comments.
Keep reading to get started.
Continue reading “Intro to Circuit Bending”