As title suggests, are the Preamp outs on the Topping headphone amps, just a alternate type of Socket of their headphone jack? Are they connected in parallel? Or is there are dedicated Preamp stage specially designed inside those amps? When I checked the specs of their headphone outs and Preamp outs all of them are same in terms of crosstalk, distortion etc. So Cant we then just use a 3.5mm to RCA from the heaphone out to get the same functionality ?