ecwl
500+ Head-Fier
Upon re-reading your post, I understand it better. Could the Blu Mk II do more than 164,000 TAPS with another DAC (like the MSB Select or even a Mojo)? This would be interesting if it did as the combo would effectively be superior to DAVE by itself. It would also give non-Chord DACs the potential to be better than the DAVE and so it would be very surprising to me if that's the case. I will know more tomorrow as I will get to hear the Blu Mk II for myself at CES.
Rob Watts can probably explain it better and more accurately. I think of taps as a surrogate of the processing power used to do the upsampling or a surrogate of how accurate the digital waveform is to the original recorded analog signal.
So Chord DAVE uses 164000 taps to upsample from 44.1kHz to 704kHz and then from 704kHz to 11.2MHz. So that's 256fs. The 11.2MHz is further upsampled to 104MHz using simpler FIR filters.
Blu Mk II uses 1 million taps to upsample from 44.1kHz to 704kHz. And that's 16fs.
If you hook up Blu Mk II to DAVE, you'll probably end up using 1 million taps to go from 44.1kHz to 704kHz from Blu and then another 82000 taps? from DAVE to go from 704kHz to 11.2MHz.
If you hook up Blu Mk II to another DAC that takes 352kHz signal, you're probably using 750,000 taps from the Blu. If it's hooked up to an MSB or other R2R DAC, it's all you'll get because R2R DACs can't switch faster the 352kHz. If you hook up the Blu Mk II to say a Berkeley Alpha Reference DAC, it'll probably take the 352kHz signal and just use simple FIR filter to upsample to say 5MHz and output that signal. So essentially, you're only getting the 750,000 taps from the Blu up to 8fs and virtually nothing from the other DACs.
Rob Watts already said that part of the reason why Hugo and subsequently DAVE's timing sounds better is because he want from 4fs WTA filter to Hugo's 16fs to DAVE's 256fs. So using Blu's 8fs 750,000 taps with other DACs probably would lose some timing accuracy compared to using them with DAVE.
Moreover, as we know, DAVE is not just about the tap length and the upsampling WTA filter. It has very sophisticated 17th order noise shaper. It uses a unique DC servo with the FPGA to remove extraneous capacitors for better transparency. I see this technology is now incorporated into the Hugo 2. And it's 20-element pulse array DAC has low noise floor and no noise floor modulation. Moreover, it has a sophisticated power supply and goes for a very transparent low noise circuitry and components.
Hence, I doubt people would prefer Blu + non-DAVE DAC over Blu + DAVE. Heck, I even suspect most discerning people won't prefer Blu + non-DAVE DAC over DAVE alone. That said, we have seen in the forums that many people have different preferences for DACs. As much as Rob Watts try to espouse the sonic and technical advantages of DAVE over DSD/R2R and SDM DAC chip designs, we see people swear by their favorite DSD/R2R/SDM DAC chip DAC. That's why I suggested that for those who just love their non-Chord DACs, they may still be able to benefit from the Blu.
