Eversolo DMP-A6 USB output to SMSL PO100 Pro to Topping D90 III?

[Bo Dacious]

I am trying to setup my Eversolo DMP-A6 to my Topping D90 III DAC.
Eversolo DMP-A6 USB output into Topping DAC works.
If I try to insert and SMSL PO100 Pro in between them, using the IIS output into the Topping, I get no sound. The light on SMSL indicates the correct format (PCM, etc.).
Not sure why it doesn't work. SMSL PO100 settings IIS1/IIS2, etc. (on bottom of unit) are correct (but changes doesn't make a difference). Are there any changes to settings on any of the units that need to be made to make this work?
It is not the SMSL unit (brand new) as a similar unit inserted -- Douk Audio XMOS 316 DDC unit -- does exactly the same thing - no sound.
Switching cables doesn't change things.
What am I missing?
Thanks.

 

[vintageaxeman]

I've had the same thing with a DDC recently. The guy who owns it proved to me that it works in his system, but something in my system just wouldn't allow the DDC to function properly. Maybe it was incompatibility, but it wasn't cables, as I tried a number of input AND output cables, to no avail.
Sometimes, things just ain't meant to be.

 

[thcdru2k]

What are you seeking to gain with the middleman?