EquipmEnt REpoRt

Description Single-box digital-to-analog converter. Formats supported: all PCM-output audio codecs (AIFF, WAV, MP3, etc.). Digital inputs: Supports up to 24-bit/96kHz (but not 24/88 via USB input), and up to 24/192 (but not 24/88

or 24/176 via optical. Analog output jacks: left/right RCA. Output impedance: 200 ohms (unbalanced). Maximum output voltage: 2V RMS. Signal/noise: 120dB, A-weighted. Ground isolation: transformer-coupled inputs. USB isolation: galvanic.

External power supply: 100–240V, 50–60Hz, 9V–1A. Power requirement: 1W.Dimensions 6.5" (165mm) W by 2.5" (65mm) H by 6.5" (165mm) D. Weight: 3 lbs (1.4kg).Serial Number of Unit Reviewed 104266.

Price $449. Approximate number of dealers: 250.Manufacturer Peachtree Audio, Signal Path International, 2045 120th Ave NEBellevue, WA 98005. Tel: (704) 391-9337. http://signalpathint.com.

specifications

with minimal deviation from perfect. But when you look at the measurements and listen closely, you realize that perfect is elusive. One has to make choices.

The last Peachtree Audio product I reviewed, the iDac ($999, Stereophile, October 2011), had two switches on the back that let the user make some of these choices of digital design. The company’s latest converter, the DAC•iT ($449), doesn’t

It’s common knowledge that manufacturers tune the sound of each DAC model. There are the facts of prod-uct design and marketing: inputs, outputs, case materi-als, price points. After that, what’s left are the trade-offs

of different circuit designs and filter options, which are chosen with care—each has a subtle yet telling effect on a DAC’s sound. Most designers try to go from bits to analog

Jon Iverson

Peachtree DAC•iTD/A converter

ELECTRONICALLY REPRINTED FROM MAY 2012

Peachtree Dac•it D/a Processor

case is superb; a wall-to-wall rubber pad is glued to the bottom.On the front are four buttons (left to right): Power, USB,

Coax, and Opt. Next to those is the infrared remote sensor. The rear panel is equally straightforward: left and right analog RCA output jacks, USB, Opt, and Coax inputs, and a connec-tor for the 9V DC wall wart (an upgrade waiting to happen?).

The supplied infrared remote control, about the size of a Snickers bar, is equally spartan, with Power, Mute, USB, Coax and Opt buttons.

let you do that. Peachtree’s David Solomon e-mailed me a bit of background on the new device: “As far as the filtering goes, it is what it is. [There is] no way to manipulate it, so we hope whoever buys one likes our particular sonic signature.”

What you getThe DAC•iT looks just like the older Apple Mac mini, or a little bigger than a stack of six CDs (our younger readers can imagine a pile of 10 iPhones). The fit and finish of the aluminum-colored

I used Stereophile’s loan sample of the top-of-the-line Audio Precision SYS2722 system to measure the Peachtree DAC•iT (see www.

ap.com and the January 2008 “As We See It,” http://tinyurl.com/4ffpve4); for some tests, I also used my vintage Au-dio Precision System One Dual Domain.

The Peachtree uses the popular Cir-rus Logic 8416 S/PDIF receiver chip. The coaxial S/PDIF input successfully locked to datastreams with sample rates rang-ing from 44.1 to 192kHz. The TosLink input would not lock to datastreams with sample rates greater than 96kHz; this is normal behavior, however, as the

TosLink specification doesn’t include sample rates above 96kHz. The USB input correctly handled data with sample rates of 32, 44.1, 48, and 96kHz, but not 88.2kHz; the DAC•iT’s Tenor TE7022L USB receiver chip is unable to operate at that sample rate, or at any rate above 96kHz. The Mac’s USB Prober utility identified the DAC•iT as being a “Peachtree USB DAC” from “Peachtree audio,” and revealed that the DAC•iT could operate as a two-channel processor with 16- or 24-bit capability in the normal “isochronous adaptive” mode. I found one anomaly: Not every music player program set the bit depth

to 24. I was using Bias Peak Pro to play my test-signal WAV files; when I played 24-bit files, I got obvious truncation at the 16th bit, so I checked AudioMidi Set-Up: the DAC•iT had defaulted to 16 bits. I believe that Amarra, which Jon Iverson used for the review, correctly handles this, but the Peachtree’s bit rate can always be manually set to 24.

The Peachtree’s maximum output level at 1kHz was 2.04V, sourced from a usefully low impedance of 250 ohms across the audioband, and it preserved absolute polarity (ie, was non-inverting). Fig.1 shows the DAC•iT’s frequency responses with data sampled at 44.1,

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Fig.1 Peachtree Dac•it, frequency response at –12dBFs into 100k ohms with data sampled at: 44.1khz (left channel green, right gray), 96khz (left cyan, right magenta), 192khz (left blue, right red) (0.25dB/vertical div.).

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Fig.2 Peachtree Dac•it, 1⁄3-octave spectrum with noise and spuriae of dithered 1khz tone at –90dBFs, with: 16-bit data (top), 24-bit data (mid-dle), dithered 1khz tone at –120dBFs with 24-bit data (bottom) (right channel dashed).

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Fig.3 Peachtree Dac•it, FFt-derived spectrum with noise and spuriae of dithered 1khz tone at –90dBFs, with: 16-bit data (left channel cyan, right magenta), 24-bit data (left blue, right red).

three digital inputs; one pair analog outputs; one Dc power jack.

Peachtree Dac•it D/a Processor

96, and 192kHz; each response follows the same curve, but with a sharp rolloff just below half the same rate. Channel separation (not shown) was asymmet-rical: the R–L crosstalk was less than –105dB below 5kHz, but the L–R leakage was –95dB at all frequencies below 10kHz. Channel separation at 20kHz was >90dB in both directions at 20kHz, which is still excellent.

For reasons of consistency with the reviews I’ve published since 1989, my first test of a D/A processor’s dynamic range is to sweep a 1⁄3-octave bandpass filter from 20kHz to 20Hz while the processor decodes a dithered 1kHz tone at –90dBFS. The results of this

test are shown in fig.2. With 16-bit data (top pair of traces), all that can be seen above 1kHz is the spectrum of the dither noise used to encode the signal; below that frequency the DAC•iT’s noise floor starts to intrude, with a very slight bump at the AC line frequency of 60Hz. With 24-bit data (middle pair of traces), the noise floor drops by about 15dB in the treble, implying resolution of between 18 and 19 bits, though the noise floor looks rather granular. At low frequencies, however, the 24-bit data’s resolution is obscured by the Peachtree’s self noise. A similar picture of the DAC•iT’s resolution can be seen in fig.3, which repeats the

spectral analysis with a more insightful FFT technique, though some curious low-level spuriae are apparent with the 24-bit version of the signal at frequen-cies unrelated to the signal frequency.

This anomalous behavior can also be seen in the bottom pair of traces in fig.2, which show the spectrum of the DAC•iT’s output while it reproduced a dithered 24-bit tone at –120dBFS. While there is a small peak at 1kHz, the traces are disturbed by higher-level peaks at 800Hz and 1.7kHz—the ESS 9023 D/A chip used in the Peachtree appears to be producing “idle tones” with these data. I looked at this behavior in more detail: As you can see in fig.4, a

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Fig.4 Peachtree Dac•it, 1⁄3 -octave spectrum with noise and spuriae of dithered 1khz tone at –110dBFs with 24-bit data (right channel dashed).

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Fig.5 Peachtree Dac•it, waveform of undithered 1khz sinewave at –90.31dBFs, 16-bit data (left channel blue, right red).

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Fig.6 Peachtree Dac•it, waveform of undithered 1khz sinewave at –90.31dBFs, 24-bit data (left channel blue, right red).

measurements, continued

PDIF supported all rates I threw at it, including 176 and 192kHz. Optical did everything except 176.4 or 192kHz. In short, if you stick to 44, 48, or 96kHz, they all work.

R2D4 WinnowingThe DAC•iT arrived just before the call for our annual “Re-cords To Die For” choices in the February issue. Each year, this triggers hours of listening while trying to do the impossible: sort down to only two album picks. I began with Creedence Clearwater Revival’s first album (SACD, Fantasy/Analogue Productions), which I’d jumped through a few hoops to trans-fer from SACD to hard drive via Foobar at 24/176. This was transferred to a DVD and sourced from my Oppo player via coaxial S/PDIF since I quickly realized that 24/176 wouldn’t play via USB.

From one of America’s greatest bands, Creedence Clearwater Revival opens in dramatic fashion with “I Put a Spell On You.” Everything was there, from the bone-shaking bass to the detailed sheen on John Fogerty’s voice. I cranked it up, and the midrange never became too edgy, as it had with some other DACs—an auspicious beginning.

Next I sorted through some recent discs from Jah Wobble, who’s been drifting from one Asian culture to another, adding his trademark dubby bass guitar and clever editing. His most recent disc focuses on Japan, but for my R2D4 I ended up choosing Molam Dub (CD, 30 Hertz HZCD12), an album from a decade back based on field recordings from Laos. The mix gets very dense in spots, and it was in

When you first plug it in, the DAC•iT’s Power light goes green—an awesome Day-Glo Mattel slime-in-a-bucket green. When you hit the green Power button, that light goes

blue, as does the current chosen in-put button. If there’s no signal at the chosen input, the input button is only outlined in blue. These blue lights are fairly bright, and might irritate in a darkened room. The main chassis and wall wart ran very cool to the touch all day long.

For $449, some compromises had to be made. There’s a switching power supply, but Peachtree says they block any of its noise from getting to the DAC with galvanic isolation (John Atkinson should be able to confirm this in his measurements), and the USB input is not asynchronous, which I’ve found to be an advantage with other DACs I’ve tried. The DAC•iT

is designed around the ESS Sabre24 9023 DAC chip, which reclocks all inputs, and, as mentioned, there are no filter op-tions—you get the choices made by Peachtree.

Another possible price-related drawback with the DAC•iT is the inconsistent mix of sample rates supported by its various inputs. Via USB, I was able to get 44, 48, and 96kHz to work, but not 88, 176, or 192kHz. Coaxial S/

The DAC•iT’s saving grace was its sheer musicality, which made listening so fun that I hardly noticed.

Peachtree Dac•it D/a Processor

dithered 24-bit tone at –110dBFS was correctly decoded, with no idle tones apparent in this 1⁄3-octave–smoothed spectrum. It was only when the signal dropped below this level that the D/A chip misbehaved. As real music never has information at this level without higher-level information also being present, this misbehavior will probably have no audible consequences.

Though its noise floor is higher than usual at low frequencies, the Peachtree still managed to correctly reproduce the waveform of an undithered tone at ex-actly –90.31dBFS with both 16-bit data (fig.5) and 24-bit data (fig.6), and with no significant linearity error until below

–110dBFS (not shown), which is good performance. A small degree of noise modulation was apparent, the noise floor rising as the level of a 1kHz tone increased from –60dBFS and –40dBFS (fig.7, green and gray, cyan and magenta traces, respectively) to 0dBFS (blue and red). Spectral peaks can also be seen in this graph at 60Hz and its odd harmon-ics, though these are all much too low in level to be audible.

When I fed the DAC•iT data repre-senting a full-scale 50Hz tone. I was surprised to see that the output was ac-tually just starting to clip, with a picket fence of low-level harmonics apparent in the spectrum, and these higher in

the right channel (fig.8, red trace) than in the left (blue). This graph was taken into the very kind 100k ohm load; reducing the load to 600 ohms resulted in the Peachtree’s output stage being fully clipped (not shown). Reducing the signal level to –10dBFS decreased the distortion harmonics to a vanishingly low level, with the second harmonic dropping from –73dB left and –70dB right to, respectively, –94 and –96dB (fig.9). A similar picture emerged with the high-frequency intermodulation test: dropping the signal level below 0dBFS dramatically reduced the amount and level of intermodulation products (figs. 10 and 11). Though there appears to be

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Fig.7 Peachtree Dac•it, spectrum of 1khz sin-ewave, Dc–1khz, at 0dBFs into 100k ohms (left channel blue, right red; linear frequency scale).

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Fig.8 Peachtree Dac•it, spectrum of 50hz sin-ewave, Dc–1khz, at 0dBFs into 100k ohms (left channel blue, right red; linear frequency scale).

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Fig.9 Peachtree Dac•it, spectrum of 50hz sin-ewave, Dc–1khz, at –10dBFs into 100k ohms (left channel blue, right red; linear frequency scale).

measurements, continued

What I discovered was that the DAC•iT didn’t have extra bottom end. In-stead, it had a slightly warmer but recessed midrange image and a very slightly soft top end. This can give the appearance of more bass, but with bass by itself, it sound-ed very similar to the other DACs. Com-pared with the Benchmark, and with even my favorite settings on the iDac, the DAC•iT’s upper midrange moved back in the soundstage—the same effect I found with the iDac’s Lo-Bit setting.

I also wanted to compare the DAC•iT directly with the iDac, which I still had on hand. I set the iDac’s filter to NOS (no filtering or oversampling) and the other switch to Hi-Bit, my favorite settings during my listening for the iDac review. Over a wide selection of music, I tended to favor the iDac by a small margin with the better-recorded tracks. The devil was in the details: The iDac had a smidgen more control with difficult and dense recordings and I tend to prefer the midrange thrown forward a tad.

On the other hand, everything sounded wonderful, relaxed, and

untangling this record’s details that the DAC•iT suffered a bit in direct comparison with my reference Benchmark USB DAC. The DAC•iT’s saving grace, though, was its sheer musicality, which made listening so fun that I hardly noticed.

Everything I threw at the DAC•iT had a deep, rich bot-tom end—so deep and rich that I began to wonder if the bass was tipped up a bit, like the Rega DAC’s. However, the problem with the Rega’s bottom end is that the extra bass is a tad woolly and leaden for my tastes. The DAC•iT’s low end felt heftier than the Benchmark’s (which no one would ever accuse of sounding tubby), but was it something else? To explore this, I cued up several electronic tracks from Tangerine Dream, then a handful of classical titles from Reference Recordings, and switched back and forth between DAC•iT and Benchmark.

The Peachtree’s

flaws are more than

buried under the

sheer beauty of

the music it makes.

Bright blue lights tell you what’s happening.

Peachtree Dac•it D/a Processor

a DC–DC converter on the Peachtree’s circuit board, presumably to increase the incoming 9V from the wall-wart supply, there appears to be insufficient power-supply headroom to cope with full-scale signals without adding some distortion. (Though it is fair to note that this distortion looks worse than it will sound on the spectral plot, due to the fact that other than the third, all the higher harmonics lie at or below –80dB.) This may well not matter with real music, or at least with classical and jazz, in which peaks only occasionally

hit 0dBFS. However, it might be a prob-lem with modern pop recordings, which bang their heads against the 0dBFS limit more or less continuously.

Though the DAC•iT offers good reso-lution, this is offset to some extent by its jitter rejection. Although it doesn’t suffer from data-related jitter, thus not amplifying the level of the high-order harmonics of the 16-bit J-Test signal’s low-frequency LSB-level squarewave (fig.12, cyan and magenta traces), some spectral spreading is evident due to the presence of random low-frequency

jitter, which also affects the DAC•iT’s reproduction of the 24-bit J-Test signal (fig.12, blue and red). This graph was taken with TosLink data; USB data gave the same result.

Considering its affordable price, the compromises in the Peachtree DAC•iT’s measured behavior seem to be well arranged in that, other than that lack of high-level headroom, they will have no audible consequences. And perhaps that lack of headroom would disappear with an upgraded external power supply?—John Atkinson

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Fig.10 Peachtree Dac•it, hF intermodulation spectrum, Dc–30khz, 19+20khz at 0dBFs into 100k ohms (left channel blue, right red; linear frequency scale).

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Fig.11 Peachtree Dac•it, hF intermodulation spec-trum, Dc–30khz, 19+20khz at –10dBFs into 100k ohms (left channel blue, right red; linear frequency scale).

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Fig.12 Peachtree Dac•it, high-resolution jitter spectrum of analog output signal, 11.025khz at –6dBFs, sampled at 44.1khz with LsB toggled at 229hz: 16-bit data via tosLink from aP sYs2722 (left channel cyan, right magenta), 24-bit data (left blue, right red). center frequency of trace, 11.025khz; frequency range, ±3.5khz.

measurements, continued

clearly knows what they’re doing, and their DAC•iT is incredibly enjoyable to listen to. The guys at Peachtree are apparently fussy listeners, and in this model their fussiness has paid off.

Hope springs eternal among thrifty audiophiles that a $500 DAC will get them all the way to $20,000 sound. I’m not sure that will ever happen, but if you’re spending under $500, or even up to $1000, this is a DAC you have to hear. n

(dare I say it) analog-like through the DAC•iT. It tamed some otherwise dodgy recordings, and never had me feeling that anything important was missing, even though I know that dinky details were sometimes MIA.

This is a DAC you have to hearI’ve listened, through my system, to the Musical Fidelity V-DAC, the Arcam rDAC, the Rega DAC, the YBA Design WD202, the HRT Music Streamer Pro, the Peachtree iDac, and the Cambridge Audio Azur DacMagic. All cost under

$1000, and each is a good-sounding DAC with a subtle yet unique sonic signature. Of those mentioned that cost less than $500, I would easily reach first for the DAC•iT. All of the DACs in this list have little blemishes in various spots, includ-ing the DAC•iT, but the Peachtree’s flaws are more than buried under the sheer beauty of the music it makes. With other DACs in its price range, I’ve always sensed a subtle cheapness to the sound, but not with the DAC•iT. (Both the

Musical Fidelity V-DAC and Cambridge DacMagic have since been released in revised editions that I haven’t heard, so you may want to check them to be sure.)

Manufacturers put their preferences out there for the public to hear, then cross their fingers. Peachtree Audio

Digital Sources Digital Sources Apple MacBook Pro computer (2.66GHz Intel Core 2 Duo, 4GB RAM, 320GB HDD) running OS 10.6.7, iTunes 10.2.2, Amarra Computer Music Player 2.2, Songbird 1.9.3, and XLD; Oppo BDP-83 universal Blu-ray player; Meridian Sooloos Music Server (Control 15, TwinStore x3); Apple iPod Touch 1G; Benchmark DAC1 USB, Peachtree Audio iDac.Preamplifier Marantz AV7005 in Pure Direct Mode.Power Amplifier Classé CAM 350 monoblocks (2).Loudspeakers MartinLogan Prodigy, MartinLogan Descent subwoofers (2).Cables USB: Cardas Clear. S/PDIF: Cardas Neutral Reference. Line level: various Kimber Kable, XLO HT Pro & S/PDIF. Speaker: Kimber Kable BiFocal XL.Accessories Dedicated 20A line for amplifiers, dedicated 15A lines for digital & analog components.—Jon Iverson

a s s o c i at e d e q u i p m e n t

If you’re spending under $500, or even up to $1000, this is a DAC you have to hear.

Posted with permission from the May 2012 issue of Stereophile ® www.stereophile.com. Copyright 2012 Source Interlink Media. All rights reserved.For more information about the use of this content, contact Wright’s Media at 877-652-5295

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