The EtherRegen does get very hot. It actually was extremely disappointing with my Krell K-300i integrated when used with the built-in RJ45 streaming. The KRELL has the very best ROON READY implementation I have ever used.
I was about to ditch the EtherRegen when I came across John Swenson’s posts or white paper on the best way to do streaming. I was under the impression fibre optical directly out of a network switch into my Sonore OpticalRendu was the best way. However, Swenson, who designed the EtherRegen and OpticalRendu recommended using a fibre conversion just before the OpticalRendu.
There are many devices that can do this such as the Sonore OpticalModule. However, since I had the EtherRegen handy I tried that, in reverse order B > A, and I noticed a slight improvement in sound, as predicted in Swensons writings. So, the EtherRegen has stuck around running hot. There are other cheaper ways to do this conversion.
I have heat issues with another LPS I bought used with my 3rd OpticalRendu. That thing runs like fire, and I no longer use it due to concerns about fire. The EtherRegen in comparison is like air conditioning.