Well, if you know the volts, and you know the amps, you can calculate the watts (Ohm's Law don't you know). If I recall, the TM733 is a VHF mobile transceiver. As such, its nominal supply voltage is 13.6. I'm not a Kenwood user, but here's a rule-of-thumb for any solid-state rig. If you know the output power, double it, and divide this by the supply voltage, in this case 13.6 volts. As an example, 50 watts out, doubled is 100, divided by 13.6 equals ±7.5 amps. It's always best to have a few amps leeway, so make sure the power supply can safely deliver 10 amps.
Just as a suggestion, if your purpose is to power this gem as a base station, look at the MFJ-4125. You can buy this unit for $99. It is small (!), delivers 20 amps continuously (25 peak), and in my case has run everyday for 14 months delivering 12 amps continuously without a hickup!
Alan Applegate, KØBG