Opera Consonance Reference DSD1.1 digital converter

Digital-to-analog converters
Consonance Reference DSD1.1
Opera Consonance Reference DSD1.1 digital converter

Opera Consonance is one of those brands that fly perpetually beneath the audiophile radar for no good reason. It’s a company that makes a range of highly respected, multi award winning products, including analogue and digital source components, valve and solid-state amplifiers, even cables and loudspeakers. The models are consistently good to excellent performers, and those who happen across them, love ‘em.

I would like to think Opera Consonance’s Reference DSD1.1 digital converter is the breakout product, the one that gives the brand the recognition it so deserves. The converter is a fully functioning digital hub, capable of processing every PCM signal it’s possible to receive and DSD to DSD256 (all through USB 2.0), as well as good ol’ 16/44 PCM files from a CD transport with any kind of S/PDIF or AES/EBU connection. It even has provision to communicate to iOS and Android devices, and the website describes a Frankenstein-grade three-way clunky way of extracting USB audio from a phone with an add-on power supply (Bluetooth is available too). The Reference DSD1.1 also has the option of being a very capable headphone DAC/amp, alongside the solid-state XLR balanced line outputs and single-ended RCA outputs that also pass through an E88CC-based triode output stage. There are also  five PCM filter settings, absolute phase adjustment, two DSD high-frequency brick wall filters, and three undefined ‘sound mode’ settings, all selectable from the front panel.

Opera Consonance is somewhat hazy on the subject of what internal architecture is used in the Reference DSD1.1, but it appears to be based around an AK4490 DAC/filter chip from Asahi Kasei Microdevices. This is a 32bit chip that can decode DSD without any internal conversion to PCM, sports those five aforementioned filters, and supports PCM files up to a notional precision of 32bit, 768kHz. It’s becoming popular as the chip of choice in some decidedly top-end devices, such as the Astel & Kern AK380 and Esoteric’s K-05X/07X disc players.

The five filters for PCM are ‘short delay sharp’, ‘short delay slow’, ‘sharp roll-off’, ‘slow roll-off’ and ‘super slow roll-off’. The term ‘sharp roll-off’ in the first and third filter equates to the standard brickwall filter found in ‘traditional’ CD replay. The three slow roll-off filters reflect the more recent trend in digital audio to reduce high-frequency digital ‘hash’ and post-ringing from an impulse response, and are often called ‘soft-knee’ filters. The two ‘short delay’ filters replace the standard linear phase filter design with a minimum phase design. This is useful in reducing pre-ringing to an impulse response. The choice of filter is largely system dependent, offering a mild tailoring of the upper registers of your player. My take on this – experiment! Start with the standard sharp roll-off, then try with the slow roll-off and switch between the two a few times over the course of a week or so. If you conclude the system sounds slightly too ‘energetic’ or ‘bright’ with the sharp roll-off, stay with the soft-knee filters; if it sounds too ‘dry’ or ‘dull’ with the soft-knee, stay with the sharp filter. Then try the appropriate ‘short delay’ filter setting over a similar time period, again listening out for the right balance between ‘energetic’ and ‘dry’. Eventually, you’ll find the right setting for your system. Note that this doesn’t change the underlying tonal qualities of the Reference DSD1.1; it’s more about fine-tuning.

The concept of a DSD cut-off filter might at first glance seem to run counter to the very concept of DSD, but in fact it’s a handy ‘get out of jail free’ card in some systems. Some DSD recordings are not as good as hoped and high-frequency component can – in extreme cases – trigger noise that filters down into the audio band. A filter at 150kHz and 50kHz can usually prevent this. Also, there are some systems where a super wide bandwidth source ‘upsets’ the input and gain structure of an amplifier designed for 20Hz-20kHz sound, and you might not discover this until you power up the DSD1.1: rather than give back your shiny new converter, this allows you to remove the high-frequency component until the next amp comes around.

The missing element in the Reference DSD1.1’s line up is any form of DLNA/UPnP or Internet streaming. However, a close inspection of the Opera Consonance line shows that task is taken up by another product in the line – the Reference 8-20 anniversary music player. The DSD1.1’s role in life is to decode, not to act as a half-way media player. Given many companies seem to think streaming means adding an off-the-shelf display, Wi-Fi board, and media player circuit to an existing DAC, and letting the end user pick up the pieces, I applaud Opera Consonance for sticking to its guns. A slightly more cynical reading of the situation is home streaming has still to make its mark in China where the company is based, and Opera Consonance’s line-up reflects that scene. However, I think the company has a more international outlook at its core, and the Opera Consonance Reference DSD1.1 is part of a wider plan. Also, if you plan on streaming, it’s a perfect match for Foobar 2000 or J River.

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