DAC Reviews

R2R, NOS/Or Not
The discrete R2R HoloAudio Spring DAC offers two main operating modes; non-oversmapling (NOS) and a chip-based oversampler (AKM AK4137). You can switch between these modes of operation by simply pushing the front panel "OVER SAMPLING" button. This button offers 4 choices; "NOS" mode which bypasses that AKM chip, "OS Mode" where PCM and DSD are each upsampled to higher rates but remain PCM and DSD, "OS PCM" where all data is "oversampled to PCM", and "OS DSD" where all data is "oversampled to DSD". If you are anything like me, you'll leave the Spring DAC in "NOS" mode, avoiding that Asahi Kasei Microdevices chip like the plague.

Skip The Bits
"Hey, you put DSD in my DAC! You put DAC in my DSD!" The buzz surrounding the T+A DAC 8 DSD is all about octuple-rate DSD; DSD512 (512 times that of CD)/22.5792 MHz. The idea being you use Signalyst's HQPlayer software to convert all of your music to DSD512 before sending it to the DAC 8 so that the latter's "True One Bit DSD Converter" can work its magic. Yea, magic.

A DragonFly Tale
[Parental Advisory Warning] I had an email exchange with my friend Joe about music and movies, as is our wont, and asked—

Me "What are listening through?"
Joe "I have two pairs of Shure 580 in-ear headphones, which are very good headphones and also sit in the ear and cut out 90% of outside noise. About as fidelity as I get."
Me "I like those Shure in-ears too. So you plug them into your computer?"
Joe "Yeah, I just plug them into one Apple product or another."

At the time, I was rich in Dragonflys, having my original and the V.1 version. So I sent Joe the original. Here's the first email I received from Joe after the DragonFly landed at his place:

Subject: Damn!

Fuck Me! Dragonfly!

Engineering Cred
Ed Meitner, the man behind EMM Labs, has some serious engineering credentials. These include a number of patents and a few decades' worth of product design and innovation including preampfification, amplification, and all things digital (like the Meitner Intelligent Digital Audio Translator (IDAT) digital processor from 1993). I owned and enjoyed the Museatex Meitner STR55 Stereo Amp back in the '90s when I was living the life of an IT guy by day and loft-living painter by night in NYC. I can still remember loving the ST55's design and sound, a nice change from the behemoths populating the floors of high-end shops like immovable metal heat generating odes to speaker design gone awry.

There's More Than One Way To Skin A DAC
PS Audio's new NuWave DSD DAC has taken some engineering cues from the company's much-loved DirectStream DAC (see review). While the NuWave does not house the same FPGA-based processing as found in its larger and more costly sibling, it does house a complex programmable logic device (CPLD), a device that sits between a programmable logic device (PAL) and a field programmable gate array (FPGA) in terms of complexity. The CPLD in the NuWave is tasked with one important job; take the incoming bits from the XMOS-based USB receiver and other digital inputs and pass it along to the 32-bit ESS Hyperstream DAC corrected; "discovers sample rate and format, reclocks all incoming data, reduces jitter, waveshapes data output to the DAC chip, and utilizes high speed/low gate count logic to reduce propagation delay for faster throughput". The CLPD accomplishes this in what the company calls "Native Mode" meaning there's no sample rate conversion employed. After the DAC, a passive filter is applied in the analog output stage.

A Rega Story
Back in the early '90s, I was on the hunt for a new CD player. I was intrigued by the Rega Planet for the same reason everyone else was; Rega built turntables and they waited years before entering the CD market with a player they felt sounded analog. Since CDs never really scratched my musical itch very well, this was music to my ears.