If you connect your DC meter to the jack coming out of the SB-220 and it has it's own voltage 12-15 volts it should work. You will need to take the amp out of standby to test the amp terminals, I assume it is an RCA Jack. you just need to be very careful to not short the two wires from the IC-7300 and preferably you should put a fuse in that is 250 ma or something like that so that in the event you do touch them together it will not hurt the radio. The RCA terminals or jacks being male coming from the IC-7300 is perhaps a bit of a design flaw. I am using the AL-811 Ameritron and it has it's own internal 12vdc supply and if you simply connected a foot switch or jumper to the amp key line it would key up. The SB-220 should do the same. I am still using the solid state switch and it works great. I hope I gave you enough information. it is quite simple. you will have to use a meter to check your amp fir polarity of the key line. You should be able to jump the key line and make the TR relay kick on and off. be sure to have it into a good dummy load for safety.
Hello Dear Bruce , very good video. I need to make one like this, I want to connect my IC 7300 with a Heathkit sb 220. Will it work?
If you connect your DC meter to the jack coming out of the SB-220 and it has it's own voltage 12-15 volts it should work. You will need to take the amp out of standby to test the amp terminals, I assume it is an RCA Jack. you just need to be very careful to not short the two wires from the IC-7300 and preferably you should put a fuse in that is 250 ma or something like that so that in the event you do touch them together it will not hurt the radio. The RCA terminals or jacks being male coming from the IC-7300 is perhaps a bit of a design flaw. I am using the AL-811 Ameritron and it has it's own internal 12vdc supply and if you simply connected a foot switch or jumper to the amp key line it would key up. The SB-220 should do the same. I am still using the solid state switch and it works great. I hope I gave you enough information. it is quite simple. you will have to use a meter to check your amp fir polarity of the key line. You should be able to jump the key line and make the TR relay kick on and off. be sure to have it into a good dummy load for safety.