Opt/Coax dissimilar in sonic character, yet useable
Nice AptX HD receiver for the price.
For the test: I am listening to YT-quality audio streaming in the same room from a Samsung Tab S5e, Dobly Atmos selected on "Voice" and system Equalizer set "Normal". In Android's Developer Options I verified AptX 24bit/48kHz with AVRCP 1.6. The tablet is running on a full charge with no optimization. System "Media" volume set at max throughout. For running the TosLink and SPDIF out, the DAC I plug into is a Topping D30 > Topping A30 (Burson V5i) > Headphones, or, 2.1 stereo: 6N3-type Volume controller > Dayton Audio SA100 > Mackie MR524. My tweeters are set at 0dB and bass drivers at -2dB, sub level set very low so its a balance. Small room.
Having A/B/Y'd the tablet's USB-C port direct against the BT 5.0 streamed Coax and Optical into the D30, as well as bypassing the D30 altogether via the BLT-HD RCA outs > FiiO Q1 Line In, here are my observations:
D30 USB: Benchmark. Direct, the dithering is not as noticeable as when streaming aptX HD. To effect this option with the Tab S5e I use a USB-C to USB 2.0 Female adapter. I've tried with a HDMI/USB/USB-C hub, but the micro-controller takes priority and causes the audio to "stutter". In comparison to the BLT-HD RCA out, I do not notice a difference in dynamics or noise over phones, only a slightly wider stereo spread.
Coax: Most notable THD among the three. More pronounced Mids and Highs in comparison to Optical, therefore slightly more fatiguing for prolonged headphone listening. Coax THD is not even perceivable over my speakers or HD 380 Pro 54 Ohm. Any RCA cable will work for Digital Coax runs.
Opt: Very low THD, Mids slightly attenuated, Highs further attenuated and slope before reaching end of the sonic range. Less fatiguing in comparison to the the USB and Coax on headphones. Dithering more noticeable than USB and Coax as well, especially in the symbols. Yet on headphones through the Topping A30 is quite good, minimal fatigue due to the slight high end roll off. Aside from the slight attenuation in the higher band, this option boasts the finest detail throughout the band.
BLT-HD RCA: Impressive DAC. Running an older FiiO Q1 off this seems to be just as good, if not better than the D30/A30 (Burson V5i) over my DT77 Pro 80 Ohm. The EQ is well balanced with a slight dip in high-mids, no "Bass" or "Gain" selected. What is nice about this option is I can select between three EQ "curves" while streaming via aptX HD: BluDentro DAC/FiiO Opamp for a slight dip in the high-mids and BluDentro digital out/Topping DAC for flat, or rolled highs; they all sound great.
Final thoughts: Initially I had only intended to make use of the digital outputs, however, I later realized the onboard DAC with the FiiO Q1 to be a worthy contender to the Topping D30/A30 stack. The onboard DAC, on paper, looks less clean than the D30, however, this is not the case, the PCM5102A can handle up to 32 bit whereas the D30's can only handle 24. Also, there is a difference between the Coax and Optical digital out in terms of their sonic characteristics, yet switching between the two outputs is similar to having a preset "filter toggle" in a sense. With the D30, I can flip between the two on the fly, and appreciate what both have to offer. For streaming YT audio, the BluDentro BLT-HD gives the streaming a Hi-Def feel and texture to the extent that you don't perceive that you are listening to YT quality audio.
Overall I recommend this unit to anyone looking for an aptX HD solution, whether as a stand-alone or intergraded component.
Cons: No ON/OFF switch.
Verified purchase: YesCondition: New