WHAT ABOUT THOSE ICOM INPUTS?
Or - "which microphone CAN I use on my ICOM ?"
Early ICOM - that's every ICOM before the great PRO series - had very low
level microphone preamplifiers. Traditionally they are - 15dB down in gain from
the standards set by Collins, Kenwood, Yaesu, etc. years ago. ICOM came to America
in the early 70's with their "zero" models 720, 730 and 740 all which had NO mic
preamps built in. The microphone preamplifiers were in the microphone ! How stupid.
This did not allow you to use any other microphone but THAT mating microphone since
half of the audio circuits were in the mic. With enough outrage and complaints they
finally moved the preamp section into the radio starting with the 735, 745,751, etc.
however, those front ends were -15 dB down in gain from everyone else, still making
it difficult to use anything but the ICOM preamplified microphones.
Our dynamic elements will work with many of those early models (not the "zero" models) by using the compression all the time at a low level. A compressor at low levels actually acts as a low level preamplifier. Adjust the mic gain to about 3/4 open and set the compression about 4 to 6 dB and those great little 735, 751, etc. usually will work with our dynamic elements such as the HC-4, HC-5, HC-5.1 and HC-6.
ICOM AMERICA knew of this problem and a few years ago invited Heil Sound to help solve the problem and solve, we did by developing our high performance Heil "iC" electret. Not the usual 15 cent import electret but a very high quality condenser electret as used in many studio microphones. The electret, by its design has LOTS of output and will drive the early ICOM rigs (not the "zero" models) to full output and sounds terrific. Your 775, 781,761,751, etc. NEVER, and we do mean NEVER has sounded better ! About time !
All of these products work well with the great little IC 706. You need the AD-1IM modular adapter and with one of the new high performance Heil "iC" elements in the "Proset iC, Proset Elite iC, or BM-10iC. If you prefer a microphopne use the iCM microphone. The IC 706 will NOT work well with our HC or PR elements, as the 706 is short on mic preamp gain, so you need to solve the low audio problem with one of the new Heil "iC" products. Be sure and adjust the carrier balance control (Q4 or Q6) for the desired transmit tone. This is VERY important.
So, the bottom line for those wonderful old 735,745,761,765,756,781,775,751, etc... use any of our products using our new high performance Heil IC electret elements. The Proset iC, Proset Elite iC, or BM-10iC, or the wonderful "iCM" microphone. These are the products that should probably be called the "ICOM FIX"
The original 746 (Not the 746 PRO or 7400) was in-between the very low level inputs of the early models and the higher input levels of the great PRO series. The IC-746 works well with our dynamic microphones - BUT you have to adjust the 746 correctly. Mic gain at 3/4 open. Compression at 50% (back panel control) and TCN (tone control network) at + 12dB for the GM and +6dB for the HC-5. The 'iCM' has plenty of drive for the 746 and sounds beautiful also.
ICOM finally got it right with their fabulous PRO series. All of the PRO series have righteous microphone preamplifiers that WILL support any of our low level high performance dynamic microphones. The best combination in amateur audio today is the Heil Classic studio microphone, the GM microphone, the Porset headsets. It just doesn't get any better. Properly adjusted, spoken into at the right distance, this combination is THE overall winner.
For the PRO series, no preamps, no mixers, just the Heil GM or Pr-781 (or any of the headsets using the HC-4, HC-5 or HC-6) plugged straight into the PRO using our CC-1 connecting cable or AD-1x adapter.
For the earlier (pre PRO series ICOM) it's the great Heil "iCM" comes complete with the connecting cable. It makes new life for those early ICOM transceivers.