I2S Input - Is It Better?

Contacting the manufactures is the best thing to do. If I had I2S capability on both devices I would want to try using it.

Go to the Jay Audio CD-2MK2 page and copy the pinout of the I2S, send it to the Holo May support and they should be able to tell you the position the dip switches need to be. I personally don’t see the point since the player only puts out redhook any of the connections would be fine I would use the AES/EBU.

I wrote to Tim Connor at Holo Audio about this and here is what he wrote in response (My question was in regards to using a Jay's Audio CD Transport with the May DAC):

"The May dac has two i2s inputs and they are both configurable to any i2s pin out if you want. But come standard holoaudio type pin out which is indentical for psaudio except dsd channel left and right are reversed. But if you are using cd the dsd channels are not used anyhow. Most likely it’s psaudio i2s pinout. But you can refer to the manual for the jays Device.
Also the May dac has a Manual too, it’s downloadable from the product page. And explains how to set up i2s if you need to change it to something different."

I also asked Tim if there was any significant improvement using I2S vs. AES/EBU and here is what he said:

"Personally I’m all about i2s. It’s the best all around. With a good Hdmi i2s cable it’s definitely a step up. The aes/eBu is as good as spdif gets bit imo Spdif is a bit dated. We have overcome a lot , if not all usb shortcoming and i2s is just beyond that. I personally use i2s always"

My May DAC is supposed to arrive next week.  I'll plan to start using the AES/EBU input with my transport at first.  Once I get familiar with the sounds I will probably give the I2S a try.  

Cheers

The best thing to do is try out both. I asked mojo audio if they could add an i2s input to their dac and they felt strongly that it would be a mistake. The basic gist of the reasoning is that if we know clock timing/syncing is essential, why would you use a technology that has three separate data streams that all need to be synced for perfect audio? This cued me to try my streamer's SPDIF output and it was indeed superior to the i2s. And that was with a 15yo monster cable vs a mid-range well-reviewed hdmi. Obviously ymmv.

Agree with what Tim said (really good dude). 

Broadly speaking AES/spdif will have a less focus in terms of imaging and staging, but the tend to have a bit more body/warmth. Bass will be a bit more bloated as well. 

I find USB in the middle and i2s on the opposite end - presenting a much cleaner sound but can be lean if your equipment downstream is.