Perhaps at this point this update will be a needed soporific.
I used the enterprise switch with a fiber optic out into to an EtherRegen and then out of Regen into ye old steamer with a dang fine ethernet cable. Sound was very very clean...a bit too clean. So.....
Removed switch (again this time a "good" one) and tried EtherRegen first with ethernet cable in and fiber optic out and then with ethernet in and ethernet out. With my gear the all ethernet sounds best. YMMV
Clean any and every thing a reap the rewards. Maybe even get a gold star?