I have been using the optical output from my “cheap Korean TVs” for about 5 years with a variety of DACs (Topping DX7s, D70, E30) and, most recently, a Soncoz SGD1. I use a 5m fibre (far longer than the TOSLINK specification is supposed to support) and I have never experienced a glitch down to a failure of any of these DACs to lock to the incoming stream.Will be interesting to see if the other devices from topping like E30, D50s or other models have the same issue
The Topping E30 appears to use the same SPDIF input device (AKM4118) as many of the more upmarket models, so unless something else is going on here.... is it possible that, in certain territories, something deliberate is being done to render the digital (i.e. optical) output unusable with certain programme material as an anti-copy weapon?