Wear headphones guys, there's clearly a whirring noise when the clutch is pushed in.
As per @
MisterSheep's comment, I do not believe this is correct. If you push the clutch in the noise occurs because there is load on the TOB, releasing the pedal also relieves the load and therefore no noise.
The noise that disappears when you disengage (press in) the clutch is usually flywheel/gear rattle, which is not what this sounds like.
To the OP, as previously mentioned you have to drop the transmission in order to access the TOB in the bell hosing. This is labour intensive (about $400-600 labour alone) so most people opt to change the clutch, pressure plate, and flywheel (or resurface it at least) at the same time.
This thread is the one you want to read.