Well since you don't have your cable hooked up, an easy test would be just to move the clutch fork so that the TOB is away from the clutch disc. If it still does it, then I would hook up the clutch cable.
Just because that's another easy way of testing. If you push in the clutch like Rick says, then you should be able to hear a differentiation in noise. Also, if you're able to engage the clutch, then that will stop the trans from turning, which will also allow you to rule in/out trans bearings. TOB's should not make noise, even without pressure on them.
Did you install the clutch disc? Did you make sure the flat side went towards the flywheel?