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Yamaha UX256

USB MIDI Interface By Derek Johnson
Published November 2000

Yamaha UX256

Derek Johnson tries out a new multi‑port USB MIDI interface that's also designed to allow connection of serial‑port gear.

The UX256 is a MIDI interface designed for connection to a USB‑equipped Mac or PC. It's housed in a half‑rack package and provides six sets of MIDI I/O — three at the front and three at the back — for a total of 96 independent MIDI channels. In addition, Yamaha have included two miniature 8‑pin serial sockets, labelled 'To TG1' and 'To TG2'. Any synth or sound module equipped with a serial port for connection to a computer can be interfaced here, which will interest Mac owners without built‑in serial ports. Each 'To TG' port can transmit up to five virtual MIDI Outs, or 80 MIDI channels, plus one MIDI Input (making the UX256 potentially an 8‑in/16‑out interface). Even Yamaha currently have no serial‑port modules that use more than 64 channels, but they say that the fifth virtual MIDI Out can be routed through such a module via its MIDI Thru, thus providing an extra 'real' MIDI Out.

Physically, there's not much more to the UX256: a power switch, 'on' and USB activity LEDs, and a socket for the external 11.5V PSU. The UX comes with a USB cable, and a CD containing driver software for both Mac and PC. Note that the PC driver is compatible with Windows 98 only, not Windows 95 or NT, and that OMS (Open Music System), which is required for Mac use, is supplied. A simple patchbay application is also included. This lets you freely route the UX256's MIDI Ins and Outs to each other, though because there are no memories on board the UX, or ways to save configurations from the software, this is of limited use. (Emagic's 2‑in/4‑out MT4, reviewed last month, has 32 onboard patch memories.)

Driving The bus

Unlike some USB devices, which draw their power from the USB lead, the UX256 requires an external PSU.Unlike some USB devices, which draw their power from the USB lead, the UX256 requires an external PSU.

Getting my computer (an Apple G4) to recognise the UX256 was quick and easy, and the Windows routine also looks simple enough. However, there was one inexplicable hiccup. Even though OMS could see all the UX's MIDI ports, every time I tried to have OMS automatically identify attached MIDI equipment, my computer crashed. Luckily, I discovered that a manually‑configured OMS setup — where I'd identified which piece of equipment was attached to which MIDI I/O pair — worked just fine.

As it happens, I was also able to check out the 'To TG' ports, courtesy of Roland's 32‑part multitimbral SC88 Pro, which has a serial connection. The UX256, via OMS, instantly saw this as two virtual MIDI Outs, as expected. It then occurred to me that a 'To TG' port could be used to hook up my currently idle serial Opcode Studio 128X 8‑way MIDI interface. To my surprise, it worked. Of course, only five of the MIDI Outs can be accessed, and just one MIDI In, but this does extend the UX256's usefulness. I wonder if Yamaha will be able to update the interface's firmware to accommodate eight Outs, and maybe even eight MIDI Ins, on one of the 'To TG' ports? That would make the UX an attractive option for the many people with serial multi‑port interfaces and a shiny, new, serial‑free Apple computer: the UX256 would provide USB‑serial interfacing as well as its own six sets of MIDI I/O.


There's plenty of anecdotal evidence of the unhappy relationship between USB and MIDI on the latest Macs, with tales of noticeable MIDI delays, timing errors and computer crashes. I myself have experienced the joys of audible MIDI delays on a couple of early USB MIDI interfaces. I was thus pleasantly surprised by the UX256's performance. Plugged into my computer, running Digidesign's Pro Tools LE MIDI + Audio software in a Digi 001 environment, the UX256 behaved flawlessly. In normal use, to my ears, there was little in the way of discernible delays or timing problems. I was eventually able to introduce some flamming and slight choking by making multiple copies of some busy parts, then routing them to multiple MIDI Outs, but at this point the data stream was improbably dense. Before you buy any USB interface, though, it's safest to get an assurance that you can exchange it if it takes a dislike to your particular setup.

Potentially, the UX256 can offer a lot of individual MIDI output channels, though few users will be able to access them all. That said, the interface still offers six I/O ports for under £200, and if you do have a serial‑equipped synth, it can be interfaced without losing a real MIDI I/O pair.


  • Mac‑ and PC‑compatible.
  • Good price for potential number of MIDI channels.
  • Bar minor OMS hiccup, I found it truly plug‑and‑play.


  • Whilst it's nice to have 256 MIDI channels, most people won't be able to access them all.
  • No 'patch' memories, and can't be used as a stand‑alone MIDI router.


A cost‑effective, no‑nonsense device which can be recommended if you don't need to store patch configurations.