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Realistic CB Power Microphone Wiring to Cobra 4-pin

Microphone Information Wiring etc, or if you just need help with choosing a good microphone for your radio.

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Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Foxhunter » Wednesday, 24 February 2010, 19:35 PM

Radio Shack Realistic CB Power Microphone Wiring to Cobra 4-pin





Asking about wiring up a Realistic CB mic for standard Cobra 4-pin wiring. Has anyone wired and hooked up a Radio Shack power mic to a Cobra CB radio and could post what the exact wiring order was, color to pin ?

I have a Radio Shack Realistic Noise Canceling With Pre Amp Cat. No. 21-1175 CB power mic and really like the sound of it. It sounded good during an initial test on my former Dalcomm MTC-101 Microphone Test Center. To my surprise, the Realistic power mic sounded good-----even without the 7V 23-601 battery that's supposed to be in it. If I paid attention to the Midland layout I could've compared it against the Cobra and had it, but I didn't. To make a long story short, the mic was wired for Midland and I went and snipped all the wires, re-tinned them, and tried to wire the mic a number of times and somehow didn't get it right.


Didn't figure out what mistake I made, and since I had trouble-----I went and checked the forum's MICROPHONE INFO section here, and didn't see anything for the mic that would help. I viewed Big Bopper's thread: Mic wiring unknown wire configuration viewtopic.php?f=32&t=12444&start=0" onclick="window.open(this.href);return false; but when I did the various tests, step for step, they didn't jive with the results from the mic wiring at all for finding the common & receive. I didn't get continuity to the remaining wires in any combination while depressing TX. I never was big on mic wiring but have done a few OEM mic's and never had a problem so far, this is the first one I've run into that's given me trouble with plug wiring.





The Realistic 21-1175 has FIVE wires and originally would have had the notorious "Realistic 5-pin DIN" connector on the mic cord.

The wire colors are as follows:

White & Braid (would be audio & shield, they are intertwined)
Black
Red
Blue (often seen listed as "unused")


Realistic Noise Canceling Mic with Pre Amp Cat. No. 21-1175.jpg


Hand Held Noise (210-1175) Pinouts Faxback Doc. # 15888
Cancelling Microphone

Pin 1.....Shield/ground (rec)..........Shield/ground (trans)
Pin 2.....Connected to Pin 4 (rec).....Floating free (trans)
Pin 3.....Floating free (rec)..........Grounded to Pin 1 (trans)
Pin 4.....Connected to Pin 2 (rec).....Audio "hot" (trans)
Pin 5.....Grounded to Pin 1 (rec)......Floating free (trans)

1 = GND/GND
2 = CONNECT PIN 4/FREE
3 = FREE/GND 1
4 = CONNECT 2/AUDIO "HOT"
5 = GND 1/FREE

1 = NO COLOR LISTED
2 = BLUE
3 = RED
4 = WHITE
5 = BLACK
http://support.radioshack.com/support_e ... /15888.htm" onclick="window.open(this.href);return false;





I wanted to wire this mic to my Galaxy DX2517. While fiddling around with this blasted mic last night, our little puppy jumped right up on my lap and knocked my mic test center down to the floor and broke it. So not only couldn't I figure out the wiring routine, but now I'm out a good mic tester as well. I'm going to throw this in a box and have it done later, but first trying to see specifically what color wire goes to what # position on the 4-pin plug. If someone would post the correct information, I'm sure it will help many others besides me out. It's frequently asked about online all over the place, but only links given to the usual wiring sites. I'd leave it up in the hopes that it would help future online visitors, otherwise I'll get it figured out eventually and just delete the post. Thanks in advance.

Anybody have a Realistic power mic wired to a 4-pin Cobra or Galaxy and can describe the wiring ?
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by tecnicoloco » Friday, 26 February 2010, 23:18 PM

Hello:

Hope this help to figure it out amigo :geek:


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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by tecnicoloco » Friday, 26 February 2010, 23:33 PM

Hello again:

I could not edit the last post :twisted:
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by tecnicoloco » Friday, 26 February 2010, 23:41 PM

oopppss galaxy wiring :geek:
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Saturday, 27 February 2010, 9:42 AM

Realistic Power Microphone 21-1175 to 4 pin Galaxy Cobra Uniden

1- Shield

2- Audio White

3- Red Transmit

4- Black Receive

Blue N/C
No Connection


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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by outlaw0814 » Sunday, 28 February 2010, 10:14 AM

you can also put the blue wire to the sheild or pin 1 this is what makes it noise canceling otherwise its just a power mike
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Sunday, 28 February 2010, 10:22 AM

outlaw0814 wrote:you can also put the blue wire to the sheild or pin 1 this is what makes it noise canceling otherwise its just a power mike
How by doing that does it make it noise canceling?

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by outlaw0814 » Sunday, 28 February 2010, 10:31 AM

it grounds out the element case some how -- i remember reading on these mikes but it was a while ago i wrote that down in my book of tricks--- dont remember exactly where i got that from think it may have come from tandy corp. when my dad had the store
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Sunday, 28 February 2010, 10:54 AM

When the ptt switch is depressed on transmit the blue wire is floating so how is that possible?

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by outlaw0814 » Sunday, 28 February 2010, 12:24 PM

ok ill have to go back and see if i can figure this out --this is what i remembered and what ihad writen down from years ago! i have one of those here somewhere ill see if i can figure it out and repost-- like i said i remember this from years ago -- havent touched a radioshack mike in a long time-- young kids always bought them to put on other radios ---god i wired so many cobra and midlands in the 80s with these things--- the one i remembered most was a trucker with a midland who had a lot of background noise and we were told to use the blu wire--
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Sunday, 28 February 2010, 13:18 PM

outlaw0814 wrote:the one i remembered most was a trucker with a midland who had a lot of background noise and we were told to use the blu wire--
Did it work?

If it did I don't see how.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by outlaw0814 » Sunday, 28 February 2010, 15:24 PM

actualy did forget 1 thing have to put a cap between white wire and blue thats where it will cut out background noise but blue still goes to shield -- yes it did work for that guy --- (and looking deeper in old boxes of paper this was in my dads handwriting and said it was from the tech at tandy corp. in 1982) god bless dad he always wrote down where and when info was gotten
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Sunday, 28 February 2010, 16:14 PM

outlaw0814 wrote: 1 thing have to put a cap between white wire and blue
Ok so what's being done is a capacitor is being added from the white audio wire to the blue wire after it's connected to shield which is the ground.

What that will do is limit the some of the high frequency response of the mic depending on the value of the cap which should eliminate some of the background noise.
Got it.

But wouldn't a simpler way to do it is just put a capacitor between the white audio wire and shield?

If you look at the schematics for RS mics the blue wire is just floating and serves no purpose.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by outlaw0814 » Monday, 01 March 2010, 15:50 PM

i would guess you could-- i am just stateing the way we have always done it -- by the way we were told to do it -- i dont have a schematic handy to really look at im using notes that i have written down
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Foxhunter » Monday, 01 March 2010, 19:03 PM

Night Crawler:

Realistic Power Microphone 21-1175 to 4 pin Galaxy Cobra Uniden

1- Shield

2- Audio White

3- Red Transmit

4- Black Receive

Blue N/C
No Connection





That is indeed it. The Radio Shack Realistic Noise Cancelling Mic with Pre Amp Cat. No. 21-1175 can be wired to a Cobra Uniden and Galaxy in this manner like said above. For some reason I struggled that night with this mic, and then when the mic tester broke I got really frustrated with it. On top of that, the continuity test results didn't match the instructional page, which puzzled me even further. Was having one of those days and felt like it was the microphone from hell.

Well I took a spare 4 pin mic plug from my extra parts case. I then soldered four 8-inch lengths of surplus telephone wire to each of the four plug pins. Now I have a dedicated 4 pin microphone test plug. I can insert the test plug into a radio (or mic tester) mic jack, and then quickly twist the microphone cord's wires to the test plug leads, and more easily do any checking & verifying before actually doing any actual soldering.


Since it's is a power mic, I'm very surprised it works like it does without a 7V battery. It sounds a little "muddy" while doing self on-air listening on a station monitor, not quite as good as it was on the mic tester, but that's to be expected. The next time I'm at a "Dollar Store", I'm going to try and grab one of those big packs of inexpensive watch batteries and make up some 7V microphone tube batteries. I think the mic might sound better once I get the preamp powered up.

All you guys----Night Crawler, Technicoloco, and Outlaw0814, I appreciate the time taken to take a look at it, posting the images & diagrams, and detail the wiring pin & color order. And again I think the information will also be entirely searchable-------for many future online viewers and visitors. Thanks for helping get it wired clearly and correctly.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Tuesday, 02 March 2010, 8:23 AM

Foxhunter wrote:Since it's is a power mic, I'm very surprised it works like it does without a 7V battery.
Foxhunter
Isn't there a switch on the microphone that allows you to take the preamp in and out of line?
If that's the case with the preamp out of line it wouldn't need a battery.

That's what it shows on the schematic for that mic.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Foxhunter » Tuesday, 02 March 2010, 8:35 AM

Top of the morning to you Night Crawler and thanks again. I see a 1-10 volume dial on the mic's upper right corner, and also a "batt test" button with an indicator light on the mic face near the grille. It just seems pretty responsive for a power mic without a battery. I'll go get a pack of the button cell batteries in the next couple of days to see if the mic is decent or not. This mic is "supposed to be" one of Radio Shack/Realistic's better microphones, along the lines of the Realistic base mic that looks an awful lot like the Cobra CA-61 etc.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Tuesday, 02 March 2010, 9:12 AM

If you look at the schematic you'll see the DPDT switch I'm referring to it's marked Power/ Normal
http://www.cbtricks.com/mic_manuals/rea ... ic_sch.pdf

Mabe you have a different version of that mic or the switch is inside.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Foxhunter » Tuesday, 02 March 2010, 10:07 AM

I see what you mean on the diagram. I'm not sure if the M1310H is an in-house number for the mic ? I wonder if possibly there were two power mic versions, one with noise cancelling and one without ? The one here is definitely a Realistic 21-1175 but there could've been more than one type or version available. Out of curiosity, I went and looked for another older Realistic CB power mic I'd acquired a few months ago to check it out. It's a "Realistic Pre-Amplified Microphone Cat. No. 21-1171". This mic is older, reminiscent of an old Sears Roebuck power mic once available, and doesn't have either noise cancelling nor a on/off switch. Similarly, it does have a 1-10 thumb wheel variable knob for output though.

Tandy Radio Shack Realistic Pre-Amplified Microphone Cat. No. 21-1171
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Tuesday, 02 March 2010, 10:23 AM

There was a base mic that RS made during the 70's it looked like a plus 2 except it was black and made out of plastic.\
I tried to find a picture of it on the internet with no luck

I cracked it open and it just had a one stage transistor preamp and a dynamic mic element about the size of a quarter.
I think it went for around $19.95

I beefed it up a little bit by adding a second transistor stage of amplification and changing the mic element and no one could tell the difference between it and a plus 2.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Foxhunter » Tuesday, 02 March 2010, 11:01 AM

Is this the one below ? It sounds like it is, and if so, then I wish I could list a model number for it-----so the next person looking for an online image of one would find it. You're absolutely correct, it is indeed a plastic Radio Shack Realistic Turner +2 (plus two) CB desk microphone. It has the variable control knob on the back of the base, and a 1&2 two position selector switch on the base underside. Takes a typical 9V battery. It's funny, neither of these mic's have plugs on them yet and aren't wired.

Also shown here is a Radio Shack Realistic Amplified Dynamic Microphone Cat. No. 21-1173 ---- from researching I found looks identical to the Cobra CA-61 desk microphone, except the head is square on the Radio Shack version and round on the Cobra version. Also, the same exact identical mic was made and branded for Hy-Gain.

Radio Shack Realistic Turner +2 Plus Two and Radio Shack Realistic Amplified Dynamic Microphone Cat. No. 21-1173
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Radio Shack Realistic Turner +2 Plus Two and Radio Shack Realistic Amplified Dynamic Microphone Cat. No. 21-1173
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Radio Shack Realistic Turner +2 Plus Two and Radio Shack Realistic Amplified Dynamic Microphone Cat. No. 21-1173
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It's funny (not), neither of these mic's have plugs on them yet and aren't wired for anything, I always manage to get the mic's that need wiring before I know if they even work or not. I've bought the spare mic plugs, but never have even tried these mic's out yet after a year. Think they're the same wiring as the Realistic hand mic ?


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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Tuesday, 02 March 2010, 12:30 PM

That's it!
:biggrin:

The hand mic uses a intergrated circuit for the preamp the base mic that looks like a plus 2 used a one stage transistor.

I know the plus 2 look alike did not have a lot of gain to it over the stock hand mic that's why I added another stage of amplification to it.

I don't know what the other base mic uses for a preamp.

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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Foxhunter » Thursday, 04 March 2010, 14:38 PM

Well Night Crawler you're the best. And I appreciate the help the other guys had posted too. I'm nearly certain that anything you had was modified for better or maximum performance, and the right way too. Wish I had your knowledge and experience, I'd be a happy man. That Realistic Turner +2 CB base microphone has that two-position switch on the underside, but for what ? Is it similar to the older Astatic D104 mic's, one position for electronic switching and another for relay switching ? Or for something different ? I have no idea what Realistic model number the mic is exactly either, it's not marked or labeled. Any wiring-coloring to pin #'s for either of the two Realistic base mic's that you would be willing to give ? I didn't get anywhere with them yet and would certainly save some headache, you can tell I haven't yet done a lot of mic wiring but have done only a few successfully so far. Either way it was great getting the help and getting this posted online, I'm sure many more aside from me will be thankful, it already comes right up in the search results from Google and other major search engines, so you all have helped me and countless others out with your supplied wiring information!

Thanks,
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Re: Realistic CB Power Microphone Wiring to Cobra 4-pin

Post by Night Crawler » Thursday, 04 March 2010, 15:10 PM

Foxhunter wrote: That Realistic Turner +2 CB base microphone has that two-position switch on the underside, but for what ? Is it similar to the older Astatic D104 mic's, one position for electronic switching and another for relay switching ? r
That's what it's for.
Foxhunter wrote: Any wiring-coloring to pin #'s for either of the two Realistic base mic's that you would be willing to give ?
If the colors of the wires are White, Red, Black, Blue and Shield and RS still uses the same color code over the past 30 or so years since that mic was manufactured then

White - Audio

Red - Transmit

Black - Receive

Shield - Ground

Blue N/C

Then apply those colors to the pins that correspond to the radio that's being wired.


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