I understand in theory anyway USB should not use or benefit from PLL as the clock for both or either (USB clock vs. PLL clock) are both in the May, if not the very same clock. For SPIDF and IS2 definitely as the May is ‘slave’ to the clock in the sending unit and PLL has been measured to effectively negate jitter to levels below the noise threshold of the measuring device.
You lost me there. Does that mean that usb is better than I2S, the opposite of the DS?
USB should not benefit from PLL circuit being enabled but it does, for me, though the measurements I’ve seen don’t support this apparent improvement. I’ve not run I2S into the May beyond a quick test with a Matrix DDC and a Singer SU-1 as they are limited to 384/768 respectively.
Better is a difficult term. I like different more. Both interfaces have pros and cons as do the other inputs.
My goal with the May was to be able to feed it 1.5Mhz PCM and ultimately 3Mhz once USB supports it. With the DS I ran I2S but was limited to 192kHz PCM by the I2S PC interface board.
My PC can only manage DSD256 over USB with less-than EC modulators and sounds too nice, lacks punch and depth. I don’t want a power hungry PC with GPU that is required to approach DSD512 let alone DSD1024. The bandwidth for max PCM and DSD is about the same ~110Mbps I think, don’t quote me.
The difference between 768k and 1.5M PCM is significant. You want it. I2S is limited currently to 768kPCM/DSD512. Not the May but any PCI sources I’m aware of.
Intel USB ports are the only sure fire way for the May to run at top PCM rates.
I have a Nucleus + running Roon, a Lumin U1 and a Matrix. Based on your experience, how should I « feed » the Holo ? Usb from Lumin ? Usb from Lumin to matrix then i2s to dac ? Usb from Nucleus (possibly with matrix) to dac? The permutations are daunting !
Upsampling in Roon ?
Thank you for sharing your experience with a Holo beginner 
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I would set it up as simple as possible and put 500 hours of playtime on it. Then experiment with your different options and see what you prefer. 3-4 combinations isn’t bad. Imagine different power supplies, power cords and USB and IS2 cables oh my…that’s a lot of potential combinations.
Roon won’t really upsample with the sophisticated math as compared to HQPlayer but is certainly just a few clicks to try and you should.
The journey with HQP will be daunting. Make sure you like the dac before considering going down this path.
I would start out with the simple path, AES or USB straight from the U1 to the May. You may find yourself happy enough that way. The Lumin software itself is very good.
So @dawkinsj , if I get this right, you own 3 DACs, the Holo Audio May, DSD Sr and La Voce S3?
Hummm … very interesting as I own the DSD Sr., but I was always intrigued by the May and the S3.
Which one, in your opinion, sounds the most effortlessly natural and non-edgy (especially the voices) ?
I owned the Aqua in it’s S2 version when it was based on the Burr Brown 1704 chipset and the DS Sr. knocked it out of rotation. When I sent the Aqua back to Italy for the S3 update they changed pretty much the entire DAC with the exception of the case and the twin power supplies. It returned as an FPGA based DAC and after a full break-in took the place of the DS Sr. Very similar voicing just more extension on both frequency extremes while remaining slightly warm and non-edgy. While the upgrade of the DS with Sunlight has brought them closer I still prefer the Aqua which is also completely modular and easily be updated in the field if needed. As to the May it is still to early to tell how it will end up at the end of the break-in period but so far I don’t find it to be forward in either of the two systems I have tried it in. My feeling at this point is that in the end the May will win out but as I have a dedicated room in two houses in two different states there is room for at least two of them and maybe all. I suspect that when it is all said and done I will order the transformers from Edcor and let WCT do the upgrade on the DS Sr to see what that does.
There are currently two La Voce S3’s for sale on US Audiomart for a good price, one silver and one black if you wanted to try it out and not lose if you decide to sell.
Like you, I have tried the S2 version (and also the La Scala MkII Optologic DAC) and at the time, I preferred the DSD Sr. In fact, I was a bit disappointed by those two Aqua DACs.
I did find out later when the S3 came out, but my memory of the S2 was not good so I did not investigate further. However, in the recent months, while searching for a DAC with a more natural tone (I was using Windom at the time), I read some reviews of the S3 and was surprised to hear the good comments, which is why I was intrigued when you said you own it.
I also read about the Holo Audio May DAC and the comments were also very good.
The problem is buying a DAC based on reviews - I know now, after listening to the well reviewed Aqua DACs and the well reviewed Bricasti M3 DAC, that I cannot trust reviews: only my ears.
While I have the possibly of listening to the S3 in Montreal, I would not be able to listen to the Holo Audio May, which is why I value your opinion as an actual owner of the DSD Sr who was able to compare it against the S3 and the Holo Audio May.
Thank you for your comparison comments: it is much appreciated.
I’ll keep you updated on the May as the process continues. At the current 24/7 rate I should be over the recommended 500 hour mark at the end of next week. As to the La Voce the S2 and the S3 are completely different animals and from several people I have talked to who have owned both the S3 and the La Scala everyone in the end preferred the S3 and moved on from the La Scala. When I bought the La Voce in 2016 Mark Sossa of Well Pleased AV was still the US distributor as well as a retailer. He recommended the La Voce to me over the La Scala even back then. Another way to get a perspective on how the three candidates fair against each other is from the two reviews David Abramson of Stereo Times did of the S3 and the May KTE. David personally owned the S2, the DS Jr., the S3 and then reviewed the May KTE. He would have bought the May if he had not just paid to order an Aqua Formula. Reviews yes but from someone who has followed the path with his own money and his opinions closely resemble what I have heard. Also contrary to some of the opinions floating around on Audiophile Style the cable used with the May does make a difference. For USB I have tried both the Inakustik and the Triode Wire Labs and the final sound is different. Same with two different brands of AES cable.
Thank you for your suggestions, Jack and Brett, they are much appreciated.
I may (pun intended) be wrong, but I think that the Holo default has DSD channels swapped, but ALT2 is identical the ps audio standard?
I don’t recall. One of the settings is compatible. I didn’t check if the channels are swapped.
Houston, the Eagle has landed 
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That’s a lot of quality (big bang for the buck) kit you have there.
Great choices all IMO, for what its worth.
Enjoy.
I’ve been experimenting with this lately. This being converting DSD to PCM on the fly. Prevailing thought usually has PCM being converted to DSD, so why not try the other way around? In my system, and to my tastes, using HQPlayer with the poly-sinc-long-lp setting, I’ve found that DSD converted to 24/88 sounds every bit as good as my DSJ/Matrix/I2S days. Sinc-M or EXT2 were good, but not as good as poly-sinc-long-lp.
I’ve been missing the exceptional ability of the DSJ to play DSD. My current Border Patrol DAC doesn’t do DSD at all. Thankfully that particular HQPlayer setting has brought the magic back out of my DSD collection.
Ideally you’d push it up to at least 352/384k (and the higher the better), why limit to 88k? Push that noise way out so its reflections don’t alter the audio band.
I’m a fan of poly-sinc-lp when I need to mellow things a bit. ext2 is like a high voltage charger and is great for mid day stuff. I find sinc-m to also be quite a bit softer/mellower vs ext2.
Ext3 and sinc-mx are both quite good but ext3 is very demanding on cpu and I’m limited there for rates beyond 768k.
Because Border Patrol only goes to 24/96. Though supposedly it can do 176, I ought to give that a try…
