ZappaMan
Headphoneus Supremus
Regards poly using optical, according to roon, it says it’s using a usb aspect. So I think it’s not using optical - otherwise how would it play dsd etc.. only know a little so could have it wrong.Thanks for all of your input.
I didn't know about the timing issues with USB-SPDIF converter.
I see the following options to connect a source with the mojo:
(a) Android Smartphone which connects to the Mojo via USB cable. Additional investment required: USB OTG micro B - B cable (5$ to 150$)
(b) DAP which connects to the Mojo via an optical cable. Additional investment required: Ibasso DX80 (cheapest DAP I found with optical out) for 200 USD used + 15-100$ for the Toslink cable (e.g. the lifatec toslink cable for 90$).
(c) USB-SPDIF converter which connects the source via USB first and then via optical or coaxial to the Mojo. Additional investment required: I have seen USB-SPDIF converters ranging from 20$ to 120$ for the Schiit Eitr to....
(d) Chord Poly which connects to the Mojo via optical cable (I read somewhere that the data transfer from poly to Mojo is via optical but I can't find that reference any more). Additional investment required: 400$ used.
(e) Less viable options: PC (Lenovo Laptop) is not really an option because it has more noise than a smartphone and no optical out. The conventional/cheap DAPs I have (Sansa Clip, Sony, Samsung; all no optical out) don't seem to provide any benefit over (a) and have worse UI.
Advantages and disadvantages as I see them for the options above:
(a)
+ cheapest
+ most compact (no additional unit)
- noisy USB cable which may decrease SQ, the theory is that of course bits are bits but RF noise is audible, see FAQ in https://www.head-fi.org/threads/chord-mojo-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/ (Spoiler: Is one the the inputs better than the other?)
(b)
+ optical cable should sound best (compared to coax and usb) also acc. to Rob Watts (designer of Mojo), see http://www.the-ear.net/how-to/rob-watts-chord-mojo-tech
- more expensive than (a) by ~ 200$.
- a little less compact than (a) because of an additional unit
(c)
- I am confused by the above feedback: My original assumption was that what matters is that there is an optical input to the mojo and nothing else really matters and a USB-SPDIF converter would provide for that. But if there is a timing issue as described here https://www.head-fi.org/threads/chord-mojo-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/page-2386#post-14149141 and other issues as described here https://www.head-fi.org/threads/chord-mojo-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/page-2386#post-14149215 then this might not be an option because it's more expensive than (a) but might produce worse SQ than (a).
+ But it could be a great solution as there are compact, inexpensive USB-SPDIF converters. The effect on SQ of such an USB-SPDIF converter is just unclear to me at this point.
- If quality of these units matters in some way and it's not only as simple as "SQ is great as long as there is an optical cable feeding the mojo" than the selection of quality units gets smaller and less compact possibly, the Schiit Eitr for example is already not really portable anymore.
(d)
+ Should sound at least as good as (b) given that it uses an optical connection to transfer data to the mojo (I forgot where I read that. Would be nice if someone had a link to confirm that). I am not sure if there are other factors that effect sound quality built into the Poly other than the fact that the mojo is fed by an optical connection.
- This post https://www.head-fi.org/threads/chord-electronics-☆-poly-☆-wireless-microsd-module-for-mojo-☆★►useful-info-on-1st-page-◄★☆.831347/page-34#post-13161612 put forth a few arguments that the Poly could be noisy in itself and effect SQ negatively. I have not seen a rebuttal to that. Has anyone?
- more expensive than (a) by ~ 300$.
- a little less compact than (a) because of an additional unit
My criteria are (from important to not so important but still relevant): Audible sound quality, compactness (I live in hotels mostly), price.
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