Your transceiver should operate properly on 12V. Try it for a while with this setting, which gives you 1.8 volts more for the regulators to do their job. If the hum is reduced, good. As was offered before, check to see if your LM317 is capable of delivering 1.5A with the heatsink that you're using. If it's LM317T it should be. If it is, disconnect the 2N3055. It is costing you overhead voltage and its emitter follower response is letting hum through.
If your transceiver is satisfactory on 12V (it's like running on the battery with ignition off) you should have no hum.