On BOTH the IC-718 and the IC-706 (versions) there is a 13 pin DIN plug on the BACK of the radio(s) that when you insert an amplified microphone (aka: power mic) THERE, instead of the front of the rigs, you are thereby bypassing the low level modulation audio input and are entering the audio chain directly into the balanced modulator.
For the IC-718, I wired a 13 pin din plug to an amplified D104 base mic and plugged directly into the back of the rig (balanced modulator) for AM usage. Rig went from approx. 40% low level modulation with backward swing to 90% modulation, crystal clear, and when I set the carrier to 10 watts I get forward swing to approx. 12 watts RMS and 20 watts on a peak reading watt meter.
Since the 718 has RCA jacks for both ALC and amp switching (make sure you use a relay or switching interface or foot key for your amp especially if it's an older one like an SB200 or SB220, etc., but even IF you're using a more modern day Ameritron, etc., it's probably a good practice), this is the way I ran my IC-718 on HF AM with good audio and fwd swing.
Now, the IC-706 (in my case, the 706MKIIG) even though the D104 works in the rear 13 pin DIN, since there are no separate RCA connectors for the amplifier switching and/or ALC, you need to use that rear DIN if you want to run an amp. Therefore, with the compressor OFF in the 706, you can use ANY good electret condenser microphone (RD-104 'Road Devil' works well, as does the $2.00 radio shack electret condenser element, or even an el-cheapo computer microphone) for use on AM, even through microphone RJ connection(s) on the front or back of the radio. You just need to remember to turn your power down to about 5-10 watts to eliminate the propensity for backward swing. There is also a very tiny microphone gain pot IN the radio that you may turn up if so inclined. Just make sure you do NOT run your compressor on the 706, turn your power down, use a good ELECTRET CONDENSER microphone, and you should have good audio AND fwd. swing on the 706.
For the IC-718, I wired a 13 pin din plug to an amplified D104 base mic and plugged directly into the back of the rig (balanced modulator) for AM usage. Rig went from approx. 40% low level modulation with backward swing to 90% modulation, crystal clear, and when I set the carrier to 10 watts I get forward swing to approx. 12 watts RMS and 20 watts on a peak reading watt meter.
Since the 718 has RCA jacks for both ALC and amp switching (make sure you use a relay or switching interface or foot key for your amp especially if it's an older one like an SB200 or SB220, etc., but even IF you're using a more modern day Ameritron, etc., it's probably a good practice), this is the way I ran my IC-718 on HF AM with good audio and fwd swing.
Now, the IC-706 (in my case, the 706MKIIG) even though the D104 works in the rear 13 pin DIN, since there are no separate RCA connectors for the amplifier switching and/or ALC, you need to use that rear DIN if you want to run an amp. Therefore, with the compressor OFF in the 706, you can use ANY good electret condenser microphone (RD-104 'Road Devil' works well, as does the $2.00 radio shack electret condenser element, or even an el-cheapo computer microphone) for use on AM, even through microphone RJ connection(s) on the front or back of the radio. You just need to remember to turn your power down to about 5-10 watts to eliminate the propensity for backward swing. There is also a very tiny microphone gain pot IN the radio that you may turn up if so inclined. Just make sure you do NOT run your compressor on the 706, turn your power down, use a good ELECTRET CONDENSER microphone, and you should have good audio AND fwd. swing on the 706.
