Small But Serious
Apogee MiniAC D/A converter
By Frank Moldstad
Page 1 of 1
Apogee MiniAC is a compact but mighty digital-to-analog (D/A) converter that can lift sonic veils from your digital audio playback. It might even cause people to look under your desk for the rack full of converters, because something this small shouldn sound this good. But it does, delivering startlingly detailed playback -- as if there no onversion?going on at all.
Roughly the size of an oversized paperback book, this stereo device will handle just about anything you throw at it, including sampling frequencies up to 24-bit/192kHz. It can be digitally connected via AES, optical, S/PDIF, S/MUX or an optional USB I/O card. Best of all, the MiniAC is a multipurpose device. Although it's designed for portability, its conversion quality puts it right at home in a studio. Analog outputs include balanced XLR jacks and an 1/8?jack for consumer-level stereo (standard 1/8?to RCA cable required). A 1/4?headphone jack is included, and the 1/8?jack is also able to drive headphones. [an error occurred while processing this directive]A companion piece to Apogee 2003 TEC-Award winning Minie A/D converter (reviewed here earlier), the two devices work together like a tag team. Between them, you can transform even an ordinary laptop into a serious audio production center. The Minie converts the incoming analog signals to digital, and the MiniAC converts the outgoing digital signals back to analog for playback. High quality in, high quality out.
USB connectivity is the key to portability, and it works smoothly on both Macs and PCs. (If you shied away from earlier implementations of USB for audio, you should give it another chance -- USB 2.0 devices are much better, not to mention the new computer operating systems.) Apogee provides special USB drivers for its Mini series devices, which it recommends that you use (although word is that Apple's Panther OS recognizes it out of the box). The company web site also has some tips about optimizing both Macs and PCs for USB operation (http://www.apogeedigital.com/downloads/usb_notes.html). I hooked the MiniAC by USB to both an Athlon-powered PC and a Mac G4, and got great-sounding playback with low latency on both platforms.
Although I didn't try it with a laptop, the USB option makes the MiniAC a natural for client presentations. You could just connect it to a laptop and some powered monitors to get better quality audio than most people have in their homes. USB connectivity also has other benefits: You can interface any non-USB device with a computer by using the MiniAC igital-thru mode?(see illustration above).
Front panel (click image for larger view)
The MiniAC interface is straightforward and sort of Twenties retro clean, with the same brushed aluminum box and purple knobs as the Mini-Me. At the center left is the Input Selector knob, where you must select the correct input source, whether it's AES, optical, S/PDIF or USB. Otherwise, the lights in the FS Hz LED ladder on the far left will blink on and off and you'll get no sound. Once you select the correct input, the LEDs stay lit on the sampling rate you're using. At the center right is the volume knob for controlling the output levels to your speakers, with L-R signal LEDs in the middle, plus a clock status LED. The headphone jack and the on-off switch are also on the front panel.
Rear panel (Click image for larger view)
The rear panel has standard S/PDIF and ADAT optical connectors and a 2x AES/EBU 9-pin D-Type input connector, where you can connect standard AES cables with an included adapter. On the right are the analog XLR outs, and the 1/8" consumer stereo out, plus the USB jack if you have the USB card. An external power supply with an extra long cord also plugs in on the rear.
I don own a high quality D/A, but it would make my life a lot easier if I did. I record digitally at 24-bit/48kHz, passing the signal optically from a Mackie d8b to a Tascam MX-2424 recorder or to an M-Audio Delta 1010-powered DAW with an optical interface. Monitors are a Blue Sky System One active monitor/sub system that make the d8b aging D/A converters sound pretty good during tracking and mixing. But most important, Ie learned a few tricks to compensate for the Mackie converters, so I can usually get what I want when mixing. It roughly equivalent to people who mix with outdated Yamaha NS-10 monitors, because they know how to translate what theye hearing.
SPECS
INPUTS:
• 2 x AES-EBU on 9 pin D-Type (breakout cable to two female XLR-3 required) handling sample rates: 44.1k-192k single-wide and 88.2 k-192k double-wide.
• S/PDIF optical on TOS-LINK 44.1/48k
• S/PDIF coaxial on RCA 44/1-192k
• ADAT 44/1-48k
• ADAT/SMUX II for 88/2/96k
• ADAT/SMUX IV for 176.4/192k
• USB at 44.1/48k
OUTPUTS:
• 2 x XLR (pin 2 - hot) for pro-audio stereo
• 1/8” jack for consumer-level stereo (standard 1/8” to RCA cable required) also able to drive headphone’s
• 1/4” jack headphone
• USB
The Mini-DAC can handle digital sample rates up to and including 192 kHz A 2x AES/EBU 9-pin D-Type input connector handles 44.1k-192k sampling rates single-wide and 88.2-192k sampling rates double wide via an included breakout cable with two female XLR-3 jacks on the other end.
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Price:
$995, or $1,195 with USB option
For mastering, I downsample to 16-bit/44.1 kHz via a Z-Sys digital sample rate converter into a Marantz CD recorder digital AES input. Then I listen to the CD in the car and in my house, evaluate what needed and go back to the studio to tweak it. So, when I hooked up the MiniAC to the mixer digital out and connected it directly to the Blue Sky monitor inputs, I had to adjust to the better audio translation. Trusting that what you hear is what youe going to get requires a leap of faith! After monitoring this way for a couple of weeks, all I can say is, I believe. Precise, detailed sound like this definitely means fewer trips around the block with my car stereo.
One of the reasons the MiniAC shines is because of the extremely low-jitter dual-stage clock Apogee has designed for it. This is the same design Apogee uses for some of its higher end converters, such as the D/A in its new Rosetta 800, an 8-Channel, 24/96 AD/DA converter. The way it's designed, the first clock stage accepts the bitstream and stores bits in a buffer, while the second stage clocks the bits out of the buffer to conversion.
This dual-stage scheme overcomes a conflict inherent in the function of any clock, according to the MiniAC manual: he clock circuitry of a typical D-to-A converter must be designed as a compromise between the ability to attenuate input signal jitter and the ability to accept any bitstream, regardless of its stability. The more the clock is allowed to track timing variations of the input, the more jitter remains in the clock at the conversion stage, with the degradation of conversion quality as a result.?So, with the dual-stage clock handling each of those functions separately, the result is a very low jitter clock for the final conversion. The combination of minimal jitter and high-quality converters is why the MiniAC sounds so good.
There are a multitude of uses for the MiniAC. It gives you audiophile-grade DVD/CD playback in a studio, a home stereo or for a portable presentation. It has inputs for just about any digital source that you'd want to connect. It's small enough to put in a briefcase, yet it looks professional in a studio. When paired with Apogee's Mini-Me A/D mic pre, it forms a complete audio I/O production system.
Apogee's got another winning product for its Mini line, which in addition to the Minie also includes the new MiniP pre-amps with the same pres as the Minie without the A/D converters. If you're looking for a versatile and professional-quality D/A, the MiniAC would be a hard one to pass up.
USB Compatibility
Mac
OS 10.2.3 except as noted below
Native CoreAudio USB drivers provide best performance with OS 10.2.3 and above. However, some OS X apps, including Nuendo 2.0, Cubase SX and Digital Performer 4, are not CoreAudio compatible and require an OS X ASIO driver supplied by Apogee. ASIO drivers are also suggested for best performance with OS 9.
ASIO drivers required for:
Cubase SX, Nuendo 2.0 & Digital Performer 4.0
(Driver available from Apogee site)
ASIO drivers not required for:
Emagic's Logic Audio, Ableton Live, and Bias Peak
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Windows
98SE, Me, 2000 and XP
Apogee-supplied ASIO drivers suggested for best performance
Windows XP note:
It is recommended that Windows XP users install Service Pack 1, which addresses known issues with USB audio
APOGEE Mini-Me and Mini-DAC
By Nick Peck
Mar 1, 2004 12:00 PM
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Apogee has released a pair of high-quality portable digital interfaces that together form a complete high-end I/O setup that's great for recording and playback on the go. The Mini-Me is a stereo mic/line/instrument preamp with a 24-bit, 96 kHz A/D converter. The Mini-DAC is a 24-bit, 192 kHz D/A converter.
Both devices offer USB connectivity. However, the Mini-DAC was designed to interface conveniently with the Mini-Me, so it takes just one USB connection to record to your computer through your Mini-Me while simultaneously monitoring with the Mini-DAC.
FROM A TO D
As an A/D converter, the Mini-Me offers 44.1, 48, 88.2, and 96 kHz sampling rates and supports 16-, 20-, and 24-bit word lengths. All three word lengths are available at 44.1 and 48 kHz, but the 88.1 and 96 kHz sampling rates operate at 24 bits only. Apogee's UV22HR dithering algorithm is automatically applied during 16- and 20-bit operation.
The Mini-Me is made of sturdy, lightweight aluminum, with the controls laid out somewhat snugly on the front panel (see Fig. 1). All connections are on the rear. When the left and right input-level controls are set fully counterclockwise, the XLR inputs on the back operate at line level instead of mic level. A pair of small, recessed screws on the front panel, which require a jeweler's screwdriver to access, are used to calibrate the incoming line level. I found this arrangement inconvenient for field recording: I'd prefer a simple mic/line input switch instead, allowing the knobs to control the level of either. When a ¼-inch instrument input is connected, the knobs automatically function as instrument-level controls. Two four-LED ladder-style input meters reside between the level controls The Mini-Me's front-panel power switch doubles as a +48V phantom-power selector. Holding the switch to the far right for a couple of seconds activates or defeats phantom power. The 12-position Sample Rate knob selects between the various combinations of sampling rates and bit depths. The Mix control sets the balance between the direct signal and the signal at the USB input. The Mix control doubles as a push button that switches between mono and stereo operation when one mic input is used. The front panel also includes a headphone level control, a switch to select dynamics processing (off, limiting only, or compression and limiting), and a switch to select one of three compression curves.
On the rear panel, the Mini-Me has a pair of Neutrik combo jacks. Mic and line signals are received through the XLR jacks, and the ¼-inch jack is for high-impedance signals only. The rear panel also has an ⅛-inch stereo headphone jack, a USB port, S/PDIF and AES/EBU digital outputs, and a power jack for the external power supply or an optional battery. For field recording, a lead-acid battery (available from Eco-Charge, Inc.) is the only way to go.
As a bonus, the Mini-Me can output digital black from the AES/EBU and S/PDIF ports at all four sampling rates when the unit is not sending digital audio information. This allows the Mini-Me to be a high-quality, low-jitter master clock-source for a digital studio. However, the unit does not have a standard BNC-style connector for dedicated word-clock output.
SIGNAL TAMERS
The Mini-Me features defeatable limiting and compression circuits to eliminate unwanted digital overs. Apogee's Soft Limit limiter begins rounding peaks at about -4 dBFs, which results in fairly transparent limiting that leaves most of your recording untouched. The Push-It compressor circuit is designed for more aggressive gain control, audibly squashing the sound and allowing an overall hotter signal to be digitized. The unit offers three preselected gain-reduction curves, but no adjustable compression parameters.
I liked the Soft Limit feature quite a bit because it let me record sharp, transient sounds — such as metal clanks — without worrying too much about overloading the circuit. It worked well on a number of sources for which the maximum dynamic level couldn't be predicted, such as concerts and loud sound effects.
I didn't care much for the Push-it compressor, however. Whether recording vocals, piano, percussion, or airplanes, the Mini-Me's compression algorithms added a hard, flat sound that didn't complement or enhance the recordings. My tendency was to stick with the Soft Limit feature, record at a slightly lower level, and then apply plug-in or outboard compression later if needed.
SURFIN' USB
The Mini-Me can act as a front end to any digital recording device through its AES/EBU and S/PDIF ports, but it also includes a USB port for connecting directly to any USB-equipped computer. Apogee has developed ASIO drivers for Windows 98SE, ME, 2000, and XP and for Mac OS 9 and OS X. The CoreAudio drivers in OS X support the Mini-Me as well. As a result, the Mini-Me works with most current DAW applications running on a laptop or desktop machine. The bandwidth of the USB protocol limits the maximum audio resolution to 24-bit, 48 kHz. However, the Mini-Me's AES/EBU and S/PDIF outputs continue to send audio at sampling rates of up to 96 kHz while you're using the USB port.
Under OS X, the CoreAudio driver recognized the Mini-Me as soon as I connected it to my computer. Configuring it as the input and output source under system preferences was effortless, and within a minute of plugging it in for the first time, I was recording audio into the shareware audio editor, Amadeus II. The audio played back flawlessly over USB, allowing me to mix the computer's signal in my headphones with audio coming in through Mini-Me's line inputs using the direct/USB Mix knob.
I used Emagic Logic Platinum 6 on a G3 iBook to test the Mini-Me in a multitrack environment. I recorded a metronome pulse, then recorded clapping against the pulse. USB latency was in the range of 40 to 60 ms, which is about what I have noticed with other USB interfaces plugged into that computer.
AIRWAVES
To record a series of WWII aircraft for a video game project, I toted the Mini-Me, a Crown SASS-P stereo mic, and a Tascam DA-P1 DAT recorder to the Planes of Fame Air Museum in Chino, California. I ran the mics directly into the Mini-Me, sending a 16-bit, 44.1 kHz signal from its S/PDIF output to the DA-P1.
The Mini-Me's mic preamps and A/D converter were a marked improvement over the DA-P1's internal electronics. The recordings of the planes' massive 60-year-old engines had a nice combination of throatiness and detail. Quiet Foley sounds, such as cockpit levers and switches, came out clean and noise-free.
In the studio, I recorded acoustic guitar, vocals, piano, and jingling keys (my favorite high-frequency test) at several sampling rates. The results were consistently musical, clean, and detailed. The Mini-Me's conversion handled the metallic high-frequency material without creating noticeable distortion or harshness.
FROM D TO A
The Mini-DAC is meant to be used at the end of the digital audio signal chain, typically feeding a pair of powered monitors. It handles a variety of inputs, including AES/EBU; coaxial S/PDIF; optical S/PDIF, ADAT, and S/MUX; and, with the optional input card, USB. All of the standard sampling rates from 44.1 to 192 kHz are supported.
The Mini-DAC has only three controls: a power switch, a level knob, and the Input Select knob (see Fig. 2). The 12-position input selector allows you the flexibility to monitor any of the four pairs of ADAT inputs (channels 1-2, 3-4, 5-6, or 7-8) coming in over Lightpipe, as well as either of the two rear-panel AES/EBU inputs at sampling rates of up to 96 kHz. In addition, you can choose to monitor the AES/EBU inputs together in double mode for 176.4 and 192 kHz operation. The front panel also includes a ¼-inch headphone jack, a set of sampling-rate LED indicators, a pair of signal-lock LEDs, and a pair of signal-level LEDs. It would be nice if the Mini-DAC had four signal-level LEDs per channel the way the Mini-Me does.
The rear panel has a power input; a S/PDIF coaxial jack; an optical jack for S/PDIF, ADAT Lightpipe, and S/MUX signals; a spot for the optional USB input; and a DB9 AES/EBU I/O jack. A DB9 cable, with two AES/EBU XLR inputs at the other end, is included. I would prefer to have two AES/EBU XLR inputs on the rear panel, but there's not enough room. The analog outputs are a pair of +4 dBu XLR jacks and an unbalanced -10 dBV ⅛-inch stereo jack.
DETAILS, DETAILS
Whether it's monitored through headphones or through the XLR outputs, the Mini-DAC's sound is clean, detailed, and unhyped, with a smooth frequency representation across the spectrum. I listened to several projects of my own as well as recordings I know very well, such as the Beatles' Sgt. Pepper's Lonely Hearts Club Band and the recent Steely Dan releases, and the Mini-DAC revealed subtle nuances and details I had never heard before. I have no doubt that the Mini-DAC would be a very useful tool for presenting an objective sonic perspective during the mixing process.
A peculiar bug popped up when I used the Mini-DAC's USB connection. When powered up, the Mini-DAC slaved to USB at a sampling rate of 48 kHz, and all of the 48 kHz files sounded terrific when played back — tight, clean, punchy, and loaded with detail. However, the 44.1 kHz files sounded terrible — noisy, grainy, and flat — because the Mini-DAC did not automatically resync to 44.1 kHz, causing improper sampling-rate conversion. Unfortunately, there are no controls in the Mac's system preferences or on the Mini-DAC to set the USB's sampling rate. To resync USB to the proper sampling rate, I had to disconnect the USB cable from the Mini-DAC and reconnect it. When the Mini-DAC received signals from the AES/EBU ports, it resynced correctly to any changes in the sampling rate.
PREACHING CONVERTERS
Apogee's Mini-Me and Mini-DAC make a fine pair. Their sonic qualities are first-rate, and their flexibility in accepting and translating a wide variety of digital formats will make them welcome in many professional studios. More importantly, they can run on battery power, and their portability, solid construction, and USB capabilities make them ideal for field and concert recording applications.
If you work only in a stationary recording studio, there are other converter options available that offer more features for less money. But if the notion of a high-quality, lightweight, and mobile recording system is of interest to you, then these babies are definitely worth examining more closely.
PRODUCT SUMMARY
Apogee Electronics
Mini-Me
mic preamp and ADC
$1,495 ($1,295 without USB)
FEATURES 4.0
EASE OF USE 3.5
AUDIO QUALITY 4.5
VALUE 2.5
RATING PRODUCTS FROM 1 TO 5
PROS: Great Sound quality. Built-in compressor and limiter. Highly portable. Rugged.
CONS: No word-clock in. Must be the master clock source. Recording through USB limited to 44.1 or 48 kHz. Line-input level can only be adjusted from tiny calibration screws. Compression algorithms are somewhat heavy. No status indicator for mono/stereo headphone switch.
Manufacturer
Apogee Electronics Corp.
tel. (310) 915-1000
e-mail info@apogeedigital.com
Web www.apogeedigital.com
Mini-Me Specifications
Analog Inputs (2) XLR/¼" TS combo jacks
Analog Outputs (1) ⅛" stereo headphone
Digital Outputs (1) XLR AES/EBU; (1) S/PDIF coaxial; (1) USB
Sampling Rates 44.1, 48, 88.2, 96 kHz (USB max. rate 48 kHz)
Mic Amp Gain Range 12-65 dB
Word Lengths 16-, 20-, and 24-bit (24-bit only at 88.2 and 96 kHz)
Dynamic Range 105 dBA
THD+N -94 dB
Frequency Response 20 Hz-20 kHz (±0.2 dB @ 44.1 kHz Fs)
Power Source 6-16 VDC (adapter included)
Dimensions 5.4" (W) × 1.5" (H) × 9.8" (D)
Weight 2 lb.
Mini-DAC Specifications
Analog Outputs (2) XLR; (1) ⅛" stereo; (1) ¼" stereo headphone
Digital Inputs (1) AES/EBU D-sub; (1) coaxial S/PDIF; (1) optical S/PDIF/ADAT/S/MUX; (1) USB (optional)
Sampling Rates 44.1, 48, 88.2, 96, 176, 192 kHz (±10%)
Word Lengths 16- and 24-bit
Frequency Response 10 Hz-20 kHz (±0.2 dB at 44.1 kHz)
THD+N -107 dB
Dynamic Range 119 dBA
Crosstalk -125 dB
Power Source 6-16 VDC (adapter included)
Dimensions 5.4" (W) × 1.5" (H) × 9.8" (D)
Weight 2 lb.
PRODUCT SUMMARY
Apogee Electronics
Mini-DAC
DAC
$1,195
($995 without USB)
FEATURES 4.0
EASE OF USE 3.5
AUDIO QUALITY 4.5
VALUE 2.5
RATING PRODUCTS FROM 1 TO 5
PROS: Great sound quality. Highly portable. Rugged.
CONS: Must disconnect and reconnect the USB cable when switching from 44.1 kHz to 48 kHz audio.
