Subjective Listening - Arrrgh!
For audio playback, we use Foobar 2000 alongside Windows Media Player. All music is transferred first to the hard drive in WAV format using Exact Audio Copy at a 4x read speed. Before we continue with subjective listening impressions, let's take a look at the measured room response of both DACs and listen to a couple of tracks without any DRC engaged.
The lowish output voltage of the passive I/V configured TDA1543 means we have to attempt to balance volume as best we can with the 2V output of the tube/transformer output of the Opus DAC for comparison purposes. After some adjustment and re-attempted measurements, we get a close enough match to see how the room responds to the Opus. Microphone gain and placement was kept at exactly the same point throughout the course of taking measurements. Each measurement was taken a number of times to see if any drastic changes could be observed.
Red=Left speaker, Blue=Right. Due to furniture placement, there is a 10dB offset between the channels at around 162Hz.
The response is of the Transparence speakers with the TDA1543 is pretty much as expected, rolling off sharply under 60Hz and over 13.5k.
Unsurprisingly, there's little to divide the two room sweep responses. The question is how both DACs sound when compared subjectively, both with and without DRC.
Listening tests are conducted using tracks from Maxwell's Urban Hang Suite and Embrya albums. Both albums feature music containing deep articulate bass lines, with vocals and instruments that should stress every part of the Bicone Signature frequency response.
Firing up "Til The Cops Come Knocking" on the Doede DAC first, the thing that strikes me is its directness. Soundstage height and depth can be best described as compact with a focused central image. This creates the perception of the vocalist sitting a couple of feet in front of the speakers. Instruments also have a "hang in the air" factor, without any real overemphasis on the finer details or decay of sounds. If "in your face" reproduction of micro details is important to you, you'll find you'll have to concentrate on hearing them with this unit in the loop. Everything's there, but you don't get buckets of spatial information that enhances micro-detail presence. Maybe that's the way it's supposed to be?
Rendition of high frequency sounds such as cymbals is on the smooth side compared to what I can recall from the Legato DACs of the Pioneer. I guess this may be a trait of non-oversampling. Overall, I'm quite impressed by the sound, considering the uncomplicated approach of Doede's implementation of the TDA1543. Subjectively, the sound has a very neutral character yet still manages to present itself without a fatiguing nature.
Now it's time to check out how the Opus fares in comparison. Both DACs are connected to the preamp simultaneously so that I can switch over quickly between the two while memory is still fresh. I spin up the same tracks from Maxwell and I'm amazed to find the perceived difference in presentation is far more apparent than I'd expected. The vocal forwardness of the TDA1543 is gone; the same vocal rendition sits further back between the speakers but has gained the impression of extending past the height of the baffles, and background instruments seem to have shifted back by a good few feet. The compact soundstage impression that the TDA1543 gave has been replaced with something far more expansive and spatial and the focus is now on all the elements of the recording. The finer details are readily apparent with the Opus; everything is projected in its own space and draws your attention. Mid-bass does not sound as prominent as it did on the TDA1543, the notes seem to be a little leaner and perhaps more analytical. Vocals and cymbals are especially alluring, something that we can put down to the sonic traits of the 3A5s on the output of the WM8741 DACs. To confirm the perceived differences I keep switching back and forth between the two units, each time amazed that the change is so apparent.