How I connect my Icom IC-7300 to an XLR Microphone

👉I recently purchased a Shure MV7 microphone to use for live streams, but I also wanted to use it for my Icom IC-7300. The Shure MV7 has an XLR output as well as a USB output, so it was ideal for what I wanted to use it for. But I ran into some troubles with noise and buzz when connected to the 7300.
In this video I show exactly what I had to build and how it goes together to get the microphone to work. This should work for any XLR connected microphone you have.
Disclaimer: I bear no responsibility for any damage to your radio, microphone or equipment. Check your model and check for voltage on the mic pin before connecting!
Buy Icom:
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Equipment used:
Shure MV7:
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Heil AD-1-IC:
👉ebay.us/REVp9y (eBay)
👉geni.us/v8IIk7 (Amazon)
connectvk.com.au/product/heil...
Isolation Transformer:
600 ohms to 600 ohms audio:
www.altronics.com.au/p/m1015-...
www.altronics.com.au/p/m1000-...
⏱️TIMESTAMPS⏱️
0:00 How I connect my Icom IC-7300 to an XLR Microphone
1:00 The Shure MV7 microphone summary
1:48 Pieces of equipment required
2:45 Problems I encountered
3:27 Wiring diagram to the Icom IC-7300
6:48 Isolation interface I built
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[@Jeeptalkshow]

It works! Since we do a podcast I have a Heil PR40, mixer, compressor/limiter/gate already, so I just needed this little device from your video and now I can connect to either my IC-7300 or IC-9700 and use the boom mic. The only thing I didn't wire up right from the beginning was the foot switch! lol Thanks for the video!

[@jeffmeyers8726]

The Heil AD-1-I adapter is made for dynamic mics and includes the DC blocking capacitor. I'm using it on my IC-9700

[@k6usy]

Yep, one cable passes the 8v, the other blocks it.

[@DK5ONV]

Good evening Hayden! Nice documentary video! A happy weekend into Downunder Land & keep up good work. 73's de Uncle Günter in SW-Germany

[@HamRadioDX]

Many thanks Gunter! Thank you for watching, I really appreciate it!

[@KX4UL]

Good information! Nice job on the isolation box. Now subbed!

[@HamRadioDX]

Thanks for the sub and for watching!

[@robvandermarel5910]

Thank you for this!

[@andrewhamop6665]

That is a truly smart, yet simple and effective little setup! I'll have to try that at some point, 73 de W8IJC!

[@HamRadioDX]

Thanks!

[@wild-radio7373]

Thank you for this! I really enjoy your work ♡♡♡ 🤜🏻👍🤛🏻

[@HamRadioDX]

Glad you enjoy it! Thanks for always watching and supporting

[@wild-radio7373]

@@HamRadioDX you betcha!♡♡♡ :) be well #hamFam

[@KC1PSK]

I have the handheld push Heil switch. What adapter do I use with the XLR adapter? It's much smaller. Will an adapter work?

[@dimitrismandrakis1161]

Thank you very much for sharing this info.73

[@HamRadioDX]

You’re welcome, I hope it helped!

[@greattime007]

Hi how are you? question i have a ic-9700 and a XLR mic with Phantom and a Focusrite 18i20. I want to connect the ic with the Focusrite line out (430 Ohms) the ic mic is 600 ohms. Is it possible to connect those 2 without any problems? 430 lin out on the ic mic in? thanks.

[@daveycrockett9447]

OR- you could have just bought the CC-1-XLR-I for $40 and used that instead.

[@dougss3480]

So what about the ALC wire. Don't we need to hook that up to the mic? Or dos ALC just still work with out it?

[@gregp74]

My little shack here has both an IC7300 and a Yaesu FT991a. I built a new shelf to hold them both and had planned on simplifying things by having one mic that could run off either one. I was hoping to just get one of those MFJ 1261 boxes to do the job, but it's looking like what I want to do is going to be a whole lot more complicated -- and expensive -- than I had planned.

[@rkguybru8632]

You might find a different mic that functions properly without all that stress. I operate a Rhode Procaster studio mic that, with the adapter cable is plug and play, and is a beautiful sounding setup.

[@markramsay6399]

Excellent video

[@HamRadioDX]

Thank you very much!

[@stankatz01]

I am using a SM 58S and did not have that problem?

[@maxxgabi]

I tested the scheme, but unfortunately I have a low dynamic microphone level... ZOOM Zdm1 and it sounds weaker than the original one from icom 7300.

[@db3mi]

i'd connect the XLR Pin1 on ground and leave the transformer mic side ground lift. Then you have a real symmetric connection to the mic. - Thank you for your work. I enjoy your channel, am not licensed (yet?) but looking for a radio. Can't decide between 705, 7300 and 991a

[@HamRadioDX]

Hope you get your licence soon! All those three radios are great choices

[@DonzLockz]

cool Hayden, good to know when I get a 7300.👍

[@HamRadioDX]

I'd probably do it differently now... I need to do an updated video

[@haydenfoy3]

Best boom mic video I've see so far. Nicely done. One question if the Heil adapter had an XLR connector on it instead of the phone jack would you still need the the isolation transformer? I'm researching a boom setup for my 991a and the Heil adapter for my rig comes with an XLR connector. 73 from KB3GRG

[@HamRadioDX]

Hi Hayden, Heil do make a XLR cable adapter. You may not need the isolation transformer if you’re mic is standalone. I had to use it because the Shure MV7 has a USB connection so I was getting a ground loop. The easiest way to fix was using a isolation transformer. Cheers!

[@donkwietniak5689]

If you are building a box anyway you could add a 1/4" jack for PTT and skip the Heil cable. The DC blocking cap is probably not needed but a good safety item, the DC will not pass through the transformer and is current limited by the radio. The Heil cable appears to be for an ic element so it would not have the cap. Also when I make interfaces like these I connect cold and hot from the mic to the isolation transformer (using a transformer designed for converting from balanced to unbalanced) and keep it isolated from ground on the mic end.

[@HamRadioDX]

Thanks Don. Very good suggestions. I got the Heil adapter anyway, but you're correct. Thanks!

[@thomasmaughan4798]

The transformer will appear as a dead short circuit to the DC. While it is true that the DC won't appear on the microphone side of the transformer, the radio side is a DC short circuit. Hopefully it is current limited. But even if so, the presence of a steady DC current in a transformer can saturate the core and change its characteristics.

[@nicgreek9993]

Could you please suggest me a good little ptt ?

[@stanleylett6649]

Great video. I have an IC7100 and also have 8 volts on the mic line. I have used a 600:600 transformer with a 100mf with the + side toward the radio but, didn't hook up the mic. I am still seeing 8 volts on the - side of the capacitor when I measure it to ground. Won't it burn out the regulator in the radio if it remains hooked up? Thanks for any assistance.

[@RobB_VK6ES]

That is to be expected. A DMM has a very high input impedance and you are reading the charged voltage of the cap. Connecting to a low impedance like the mic amplifier will drag down this voltage and no DC current can pass the cap. So in short assuming everything else is wired correctly you should be OK except 100 millifarads is far too much. Aim for 1 to 5 microfarads.

[@christerpstra6032]

Thanks for the video. I had my microphone going through some EQ stuff via the W2IHY Ibox into the ACC connector in the back of the 9700. Worked fine but when I tried Dstar there were malfunctions, sadly enough. Bought the SM-50. But I was wondering: wouldn't it be possible to use the ACC input on the back? Volume control is only working when the front entrance is use but had that sorted on the external equipment. All the best, 73 Chris PAØTVI

[@HamRadioDX]

Yes the ACC socket would be possible for sure. I didn't look at it as I had already ordered the Heil mic, but definitely a few different ways to interface it for sure. Thanks Chris!

[@justinmadden308]

You will get much better low frequency smoother lows going in thru the back of radio , avoid going in thru the front end its gona kill your audio reaping from that mic .

[@orbiquity]

Are we not just better off getting the Heil adapter that accepts an XLR microphone? It sounds like you had to do a lot of extra steps because you didn’t get the XLR adapter. I have an AT2020 and would like to know if it works with the Heil adapter.

[@k6usy]

Heil sells 8-pin to XLR cables for icom rigs… it’s a one cable solution.

[@TheNoCodeTech]

#ThNHR #TeamReplay for the win. Nice tutorial type informative video, thanks.

[@HamRadioDX]

Thanks No Code, always good to have you watching

[@dm9gp]

Does the radio's manual explain how to switch off phantom power from the radio to the mike?

[@HamRadioDX]

No I don’t think so, but I’ve heard there is an option on the 705 to turn off power to the mic, I think in the menus somewhere, but that’s a different radio altogether

[@daveherron]

I hadnt considered this while looking into something like this for the IC705. Turns out, it has an option to Enable/Disable the 8V output to MIC. I used to have the 7300 but dont recall if it had the option or not.

[@HamRadioDX]

I didn’t know that, where is the option to disable the 8V?

[@daveherron]

@@HamRadioDX For the 705 at least, its under Menu, Set, Connectors, MIC Jack 8V Output - On / Off. After looking at the manual though, if its set to Off, it sends 3.3V instead of 8V. Not sure if that would eliminate the hum.

[@qw-]

This is a dynamic microphone, you need at least 25 dB of gain. A single transistor preamp circuit is needed to raise the level a bit

[@clems6989]

Radio has built in compression / gain adjustable.

[@HenryYong]

Can you connect from dynamic microphone to an audio recorder (eg Zoom H5) for preamp, and output Line Out to Heil 3.5mm socket?

[@thomasmaughan4798]

Line out from a Zoom (I have H4N) is too strong for a microphone input but you could take the line out of the Zoom and put it in the rear audio line input jack.

[@FFdo.]

I have th H5 and have used it for years with the 7300. I use the INPUT 1 and 2 with the PR-781 and a AudioTechnica BPHS1 and I can switch between the two microphones by pressing the button 1/2.

[@scottnaples1512]

I stand corrected. The IC 7300 does in fact have voltage on pin 1, the audio. My apologies for creating any confusion. 73's.....

[@Jeeptalkshow]

The AD-1 adapter on the mic input side says "with cap" Does that mean the 1 mf electrolytic cap isn't needed for connection to the audio transformer?

[@HamRadioDX]

That's correct, if it says with cap then that isn't needed. My adapter didn't have one

[@Jeeptalkshow]

@@HamRadioDX Thanks for the quick reply. It's only a cap, but I didn't have one and was going to have to order a bunch to get one. ;)

[@daveduffy2292]

This is a great tutorial. How does it work with 400watts output

[@HamRadioDX]

Don't have an amp that does it.

[@JohnVK5JAK]

Question/suggestion. Why did you use an RCA Socket on the isolation box? An RCA to 3.5mm jack cable isn't a 'common' item. Had you used a 3.5mm socket, you would have more chance of finding a 3.5mm to 3.5mm cable in an emergency (out in the field) should you forget the RCA cable. Also, when you had the hum (before you made the iso box) how did you stop the 8 volts getting to the mic?

[@HamRadioDX]

RCA socket was in the junk box. I also was not planning on using this in the field, just in the shack where it never gets touched. I used a cap to block the 8V DC which was built into the Heil adapter tail. The hum came from a ground loop when the USB from the mic was plugged in.

[@rohnkd4hct260]

When I did video editing all my sound was XLR.

[@JaazznMaannn]

Finally a video for my liking, yeeea ;) Question, does this box work for a mixer to. My Mixer a Beringer Xair18. My dynamic mic is connected to the mixer and want to use a AUX for my radios, IC-9700 and IC-7300. So I guess i need 2 boxes one for each radio, connected to AUX 1 and 2? Looking for at schematic of mixer connection like the one you showed us in your video ;) Keep up the good work ;)

[@HamRadioDX]

It should work yes. It’s a fairly simple box, it’s just the capacitor to stop voltage from the radio coming down the mic line and isolation transformer to isolate the radio from the mic electrically (done to prevent ground loops with the USB). I would experiment but I think it would work, just make sure no phantom power is traveling up from the mixer toward the radio!

[@JaazznMaannn]

@@HamRadioDX Yea phantom 48v is probably not good for the radio ;) Grounding is an issue i guess. So grounding Radio, mixer and PC would probably be a good thing ;) Thanks for your videos ;)

[@HamRadioDX]

@@JaazznMaannn yeah 48V might hurt! Grounding may help, although be wary of ground loops which is the problem I had

[@paulhastings3109]

What lead you to the shure over the Heil tnxs 73 down under

[@HamRadioDX]

I use a normal XLR male to female cable to the box that I made up that has the transformer in the box. From the transformer box to the Heil is a RCA to 3.5mm mono.

[@thomasmaughan4798]

Heil microphones are difficult to obtain right now and Shure is considerably less expensive depending on which one you use.

[@bradclark8528]

KN60UT - Question - I heard on the video that a link would be posted to go through the isolation transformer connection in more detail. Where can I find the link. I'm a brand new ham and this is going to be fun! Thanks all. Brad

[@HamRadioDX]

Hi Brad, there are links to the transformers in the description that I used. There is a schematic in the video, but I have made a change. Send me an email for more info and I can also send photos. Thanks for joining as a member! 73 [e-mail]

[@bradclark8528]

@@HamRadioDX Thanks so much. [e-mail]. have a great weekend!!!

[@bradclark8528]

@@HamRadioDX Thanks. My e mail address is [e-mail].

[@nicknitro4420]

None of this is necessary if you use the 13 pin din connector out of the back of the radio.. You will override the front mic circuitry.. Pin 2 (GND) and pin 11 (MOD).. straight into your mixer..

[@frankjohnson7204]

The 13pin ACC socket only has a "line" level" audio input. There is insufficient gain for a microphone without an external pre-amp.

[@nicknitro4420]

@Frank Johnson Correct when using a mixer or pre amp.. kzbin.info/www/bejne/bKKoZq2abNeMrZo

[@M0JHN]

In music industry that’s called a DI box

[@TangoOscarMikeN3WS]

#teamreplay Well done.

[@k2icc]

Sound sample test?

[@HamRadioDX]

Have a look back through my live streams where I've been contesting such as this one here - bearing in mind that audio is taken off the audio monitor on the radio - kzbin.info/www/bejne/o3OteGOIl7itgrs

[@k2icc]

@@HamRadioDX I used the Shure SM7B, and also a condenser mike, but everyone says the factory mike sounds a lot better, amazing and louder. Just wondering what results others are having. Thanks a lot. 73.

[@kevinkc3onohelijeepworld953]

That cap should be part of the Heil cable from what I remember hearing ? Send Bob a email asking 😉 thank god for that 7300 keeping torroid makers in business with rf squeezing in every where 😔 never seen a rig that needs so many input/output chokes. Yikes 😬😲

[@HamRadioDX]

It should be, but my packaging had "no cap added" sticker on it

[@kevinkc3onohelijeepworld953]

@@HamRadioDX scary without that blocking cap you will cook sum elements 😳

[@HamRadioDX]

In my setup I wasn't too worried about cooking elements in mics, but cooking the regulator in the radio. With the isolation transformer, the other side goes to ground, so effectively you'd have a short across that +8V line to ground!

[@timjohnson5250]

@@HamRadioDX The AD-1-I8 is the correct cable with the cap.

[@scottnaples1512]

Actually, there is no 8 volt going thru the Heil Mic Adapter. It utilizes audio in and ground only for the audio. The 8 volt pin on the main connector is used only for Icom mics. If you're connecting other mics then yes, you need to be careful not to use that pin. You will still need an audio ground isolator to eliminate any possible hum and stop any ground loops. Good video though and I enjoyed it.

[@radiotvgod]

Could you please clarify this by stating the pin numbers?

[@ess2870]

@@radiotvgod There's 2 styles of adapters. AD-1 AND AD-1C. One style is for dynamic, the other is for cart/electrec mics. Not sure which so verify what you need...

[@radiotvgod]

@@ess2870 I need both but which is which?

[@radiotvgod]

In other words, what are the pin numbers?

[@ess2870]

@@radiotvgod counterclockwise they are 1-8. With the indent at the 12oclock position. 1. Mic Input 2. 8v DC OUT 3. FREQ +- 4. Main readout squelch switch 5. Ptt 6. Ptt ground 7. Mic Ground 8.(center) Main Readout AF output

[@thomasmaughan4798]

It is better to NOT ground either side of the microphone balanced cable. Three pins for a reason; ground the shield but not either of the signal wires.

[@pburgvenom]

yup

[@chrystalsmith8732]

You're going to way to much trouble. Use the AD-1-I and that's all you need. It has the blocking cap in the adapter.

[@Pivotal_Moment]

Why would I "Like" and subscribe at the very beginning of the video, if I haven't watched it yet?? (Maybe that should be suggested at least halfway thru the presentation. Just saying 😉)

[@paulwithers1803]

L

[@jeromegrzelak8236]

to much stuff

[@HamRadioDX]

Glad you liked the video!

[@mewcomm]

He takes 3 minutes to get to the point. This is mostly about selling his channel. If you’re interested in relevant information quickly this video is a waste of time

[@HamRadioDX]

Glad you liked the video! Lucky you didn't waste too much time typing this comment, I know it's valuable beyond comprehension.

[@pburgvenom]

SM-7 is a great mic

[@pburgvenom]

Bal vs Unbal