If I go over to the console and put my head near it I'm sure I'd hear it, but under normal circumstances (around 10ft from the console) I only ever hear the disc spinning. I'm not the heaviest user (a couple of hours at a time as a rule) and I live in a fairly cool climate (UK).Honestly I think that if you aren't hearing the fans at all, that's cause for concern. If the fan isn't kicking in, then where is all the heat? Still inside the console surely?
Sounds like the Transistor thing is something that should be fixed.