Rotel RDD-1580 Digital-to-Analog Converter

Great Digital Made Affordable

Equipment report
Digital-to-analog converters
Rotel RDD-1580
Rotel RDD-1580 Digital-to-Analog Converter

It’s an amazing time for computer-based audio. It wasn’t too long ago that DACs connected to a PC or Mac were limited to CD-quality resolution and relied heavily on upsampling or multiple conversions to match the capabilities of transports. What’s better than a computer that manages a seemingly unlimited number of high-res songs at 192kHz/24-bit (or higher)? Here’s what: the fact that you can now own an entire computer-based system at a fraction of the cost of components from just a couple years ago, without sacrificing sound quality. As with all facets of life there will always be über-expensive gear that can do it better, but the new $799 Rotel RDD-1580, with its myriad inputs and superb design, represents an affordable option that won’t become obsolete in a few years. Plus the RDD-1580 is more than just a checklist of features; it’s a true hi-fi component with gripping sonics that run with the best of ’em without running you into debt.

Back to Basics
First and foremost, a DAC should have the ability to handle any digital input you could ever hope to use. There’s no point in purchasing one component for your transport, another for your computer, and then another for your iPod. The Rotel RDD-1580 has six inputs: two optical TosLink, two digital coax, one computer USB, and one iDevice USB on the front panel. It’s easy to scoff at that last one, because the front-panel USB input is limited to 48k/16, but it’s a great option when friends come over and want to play “that new song you just have to hear” without the hassle of ripping the music from their iPhone or iPad onto your computer. The front-panel USB input also doubles as a charger, which was super-helpful when my iPad—aka my computer-audio command center—ran out of juice.

For high-res computer audio, I connected the RDD-1580 via USB and TosLink to my iMac with an external 12TB RAID NAS drive, selected the Rotel under outputs, then fired up iTunes with Amarra Hi-Fi. It’s nice that most Macs feature optical and multiple USB outputs, because that not only allows for easy A/B comparisons from the same source, it also allows for comparisons with multiple DACs. Like I said, it’s an amazing time for computer-based audio.

Maybe I’m a bad reviewer for admitting this, but I no longer use a transport for SACDs—I rip all of my SACDs to my computer using a Playstation 3. Caveat: This requires an older firmware version that can read SACDs and convert them into an ISO file, then more software to convert the files into PCM that can be streamed to your DAC, all of which can be a little daunting for a newcomer to computer-based audio. If you have a large collection of SACDs, a transport is still the easiest option; but if you’re up to the challenge it can be fun—yet very time-consuming—to finally transfer those SACDs to your computer and break free of the physical constraints of changing discs. This topic probably warrants an entire article, but let’s get back to the DAC.

Rotel has long been known for high-quality components at an affordable price, and the RDD-1580 is no exception. Unlike most DACs in the same price range, the RDD-1580 features two Wolfson WM8740 converters—one for each channel—a Rotel-designed toroidal transformer, and slit-foil capacitors to supply the DAC with great power. If you’ve been following DAC technology for a while, you’ll know that sound quality is not just about the quality of the converters, but also the digital filters, output stage, and power supply; in this regard the “dual-mono” design of the RDD-1580 really shines. Unless you are getting into DSD, this DAC has everything you need to rule the digital world. Oh, and it has a remote! More on that in a bit (pun intended).

Bits, Bytes, and the RDD-1580’s Sonic Capability
If the world of digital audio were simply eight bits in a byte, any ol’ DAC would do. It’s the aggregate design that counts, not just the mathematical sum of its parts. When I listened to the RDD-1580, it was obvious that Rotel always had high-quality analog sound as its goal. Sound quality seems to be an afterthought for many sub-$1000 DACs that have the capability to handle 192/24 PCM signals; heck, there are $30 DACs that can do this. For those of you who remember the early mindset when turntables were simply something that spins a record, this will be a little déjà entendu.

When testing DACs, my go-to music is always something from the Ultimae record label, purveyors of incredible ambient soundscapes from artists like Aes Dana, Solar Fields, Hol Baumann, and Carbon Based Lifeforms. This type of music is perfect because it’s not only great to listen to, but also pushes the limits of a system in a controlled manner that orchestral movements just can’t touch. Ambient music plays with soundstage width, depth, height, and extreme frequency response with lightning-fast speed. Such ambient music is like a modern-day version of classical music in that it paints a landscape and takes you on a journey, except that the sound is phasey left and right, front to back, and top to bottom.

What’s amazing about the RDD-1580 is that it took the massive amount of sound from Solar Fields’ Movements and translated it into a beautiful soundscape that was far wider and deeper than that of my comparison DAC, which retails for about the same price. On “Sol,” the first track of the album, the bass seemed to rip from the ground and leap into my chair, while simultaneously the high-frequency zips-and-zaps flew from beyond the outer edges of the speakers to land centerstage, dance in mid-air, then retreat well to the rear. With the comparison DAC the effect was “similar,” but the soundstage was truncated, never extending beyond the edges of the speakers, and had about half the depth. This was using the same USB cable, the same computer—same everything. For the same price, the RDD-1580 put the comparison DAC to shame, and was far more engaging in its ability to elicit a visceral response to the music. Several times during the track “Discovering” I caught myself clenching my fists and sliding toward the edge of my seat, all because the RDD-1580 made the music that much more gripping.