There is no lack of small, affordable USB audio interfaces in the world today. But distinguishing attributes do exist among them, and Edirol's UA-25 is one flush with useful features that make it an attractive option. In particular, if you use a laptop and travel a lot, it's nice to have a compact, all-in-one interface that allows you to knock out a vocal on the road or take a console feed at a concert or event. And although portable use is the more obvious application, this interface is every bit as useful in the studio.
NO BIGGER THAN A BREAD BOX
First of all, this box is surprisingly small: 6.5 inches wide, 5.25 inches deep and 1.75 inches tall. It's about the size of a large sandwich (and isn't much heavier). That's what makes this unit perfect for the traveling producer. It will easily fit into a soft-side laptop bag. Awhile back, I had to record remotely and wound up dragging along a mic pre, a compressor and an interface to get the signal into the computer. This box replaces all three and would have been most welcome. Like most such portable interfaces, it has two channels of analog input. It uses the clever Neutrik connectors that allow either ¼-inch or XLR plugs. It also provides switchable 48V phantom power so that you can use condenser mics. Power is derived from the USB bus, but there is one caveat: If your computer, like mine, already has 437 USB devices plugged in, it probably won't be able to successfully power the interface. The use of a powered USB hub solves the problem handily, or if you can temporarily eliminate your other USB devices, you'll be fine. This is yet another feature that makes this interface great for remote recording. A nice blue LED indicates an active USB connection.
Phantom power is not switchable per channel, but it is only available on the XLRs. Thus, an XLR-to-TRS converter will allow you to get around any potential conflicts. Also present are input sensitivity knobs for each channel, and input impedance can be switched between Hi-Z and Lo-Z on channel 2 — perfect for recording a vocal on channel 1 and a guitar on channel 2, for instance. A switchable analog limiter is also featured on the inputs. A green LED indicates limiter activity when it's switched on and a red LED indicates clipping when it's not. Digital I/O is optical only, which is a bit of a disappointment, because coaxial RCA S/PDIF is a lot more common. Nonetheless, optical is becoming more the rule than the exception, so this is not a big deal. A red LED indicates digital input mode.
A stereo/mono switch determines whether monitoring of the inputs happens in stereo or mono, which is nice if you're tracking a single channel. This is only the case when using the analog inputs. A Direct Monitor switch determines whether you're monitoring the inputs directly to eliminate latency or through the computer. The UA-25's driver software enables changing the buffer size to help keep latency as low as possible. The unit has a headphone jack and level controls for both it and the master (control room) outputs. The unit sports both +4dBu balanced ¼-inch and -10dBu RCA master outputs with identical signals, enabling you to route signal to a recorder and to monitors simultaneously. A nice bonus with the UA-25 is MIDI I/O, with a single Input and Output. Many users have portable keyboard controllers, so it's nice to be able to work on tracks on the airplane when you're flying to and from a gig.
An Advance switch on the unit determines how it behaves in regard to the computer. With the switch on, Edirol's software driver enables as high as 24-bit, 96kHz sample-rate operation. Otherwise, using the audio driver included in your OS, basic 16-bit, 44.1 or 48kHz operation is the default. An important note: When in 96kHz mode, the unit can either record or play back at one time, not both. Also, MIDI is only available in Advanced mode. And, of course, 44.1, 48 and 96kHz resolutions are all available. With Windows computers, WDM, MME, DirectSound and ASIO 2.0 protocols are supported. For Mac OS X users, CoreAudio, ASIO 2.0 and CoreMIDI are supported. Edirol includes drivers for Mac OS 9 users, enabling ASIO 2.0 compatibility, and via OMS, MIDI can be handled, as well. MOTU's FreeMIDI is also supported — a nice touch.
READY TO GROOVE
After I opened the box and pulled out the unit, I was literally up and running in about two minutes. The setup is definitely no-muss, no-fuss. I needed to record a spoken vocal for a house track, so I plugged in a good condenser mic in preparation for recording into MOTU Digital Performer 4. I applied phantom power, dialed up an appropriate level and started recording right away. After I made adjustments in DP4's hardware dialog, the UA-25's inputs and outputs were immediately available. The quality of the mic pre was great, as was the conversion. I used the limiter to help keep level in control, and it was very transparent. There was no audible pumping or ridiculous brick-wall slamming of the signal — just nice, clear audio.
The UA-25 is solidly built. Its metal box feels quite sturdy, and the controls don't feel wobbly or cheap. The mic pres are not $2,000 Class A systems, but they sound good. The converters also exhibit good quality, obviously more so at high resolution. This interface was clearly designed for people on the run — it slips into your computer bag and gives you a lot of power for such a small box. If you need a high-quality, portable audio and MIDI interface, the UA-25 is a great value.
UA-25 > $295
Pros: Portable. Good quality. USB-powered.
Cons: No coaxial S/PDIF I/O.
MAC: G3/233; 64 MB RAM; Mac OS 9.x/OS X; USB port; OMS 2.3.3 or FreeMIDI 1.35 (Mac OS 9.x only)
PC: Intel-compatible/600; 64 MB RAM; Windows 98/98SE/2000/ME/XP; USB port (Intel USB chipset recommended)