What’s the best mic for a cobra 29 classic ?

[Tokin]

When i key the mic, i can see the carrier raise, but sometimes when i talk it wont modulate,nor can i hear myself on the talk back. Now if i unkey the mic and start over most of the time it works fine. I can also key the mic and move the button around alittle i get some static interference in it as if something is not making up good.

Here is what I just found.
Not all cobra coffin mics are the same. While working on mics today I was having a problem wiring what seemed to be your typical coffin mic with a 5 wire cord, yellow, shield, black, white and red. I finally grabbed another period cobra coffin and opened it up. This one is 4 wire, shield, red, black and white.
In the process I found the 5 wire mic wasnt working properly. Sometimes I key and I had no audio but my mic tester was showing tx. I found the ptt armature was flexing a little and not pushing the switch plunger in far enough and wrapping the end that makes contact with the switch plunger with some black tape fixed the issue. You may want to try some shrink tube for a better repair.
What I also found was there are different designs cobra used over the years. Here are 2 ive found so far.
The one on the LEFT is what I believe to be an original coffin mic. Its stamped "made in Japan", the one on the RIGHT is not marked and has a 5 wire cord.
Wiring is as follows:

4 wire Cobra coffin mic "made in Japan"
Com = Shield
Audio = Red
TX = White
RX = Black

5 wire version "no manufacture stamp"
Com = Black & Shield
Audio = Yellow
TX = Red
RX = White
Bottom pic shows the made in Japan mic on the right and I noticed some mold design differences between the two.
Just wanted to document what I found so others wont pull their hair out trying to wire a simple Cobra stock and hopefully solve what may be a common issue caused by a design flaw.

 

[sunbulls]

Here is what I just found.
Not all cobra coffin mics are the same. While working on mics today I was having a problem wiring what seemed to be your typical coffin mic with a 5 wire cord, yellow, shield, black, white and red. I finally grabbed another period cobra coffin and opened it up. This one is 4 wire, shield, red, black and white.
In the process I found the 5 wire mic wasnt working properly. Sometimes I key and I had no audio but my mic tester was showing tx. I found the ptt armature was flexing a little and not pushing the switch plunger in far enough and wrapping the end that makes contact with the switch plunger with some black tape fixed the issue. You may want to try some shrink tube for a better repair.
What I also found was there are different designs cobra used over the years. Here are 2 ive found so far.
The one on the LEFT is what I believe to be an original coffin mic. Its stamped "made in Japan", the one on the RIGHT is not marked and has a 5 wire cord.
Wiring is as follows:

4 wire Cobra coffin mic "made in Japan"
Com = Shield
Audio = Red
TX = White
RX = Black

5 wire version "no manufacture stamp"
Com = Black & Shield
Audio = Yellow
TX = Red
RX = White
Bottom pic shows the made in Japan mic on the right and I noticed some mold design differences between the two.
Just wanted to document what I found so others wont pull their hair out trying to wire a simple Cobra stock and hopefully solve what may be a common issue caused by a design flaw.
View attachment 37885 View attachment 37884 View attachment 37883 View attachment 37886

I was about to comment on that same issue, but you saved me the trouble by describing it better.

 

[543_Dallas]

Here is what I just found.
Not all cobra coffin mics are the same. While working on mics today I was having a problem wiring what seemed to be your typical coffin mic with a 5 wire cord, yellow, shield, black, white and red. I finally grabbed another period cobra coffin and opened it up. This one is 4 wire, shield, red, black and white.
In the process I found the 5 wire mic wasnt working properly. Sometimes I key and I had no audio but my mic tester was showing tx. I found the ptt armature was flexing a little and not pushing the switch plunger in far enough and wrapping the end that makes contact with the switch plunger with some black tape fixed the issue. You may want to try some shrink tube for a better repair.
What I also found was there are different designs cobra used over the years. Here are 2 ive found so far.
The one on the LEFT is what I believe to be an original coffin mic. Its stamped "made in Japan", the one on the RIGHT is not marked and has a 5 wire cord.
Wiring is as follows:

4 wire Cobra coffin mic "made in Japan"
Com = Shield
Audio = Red
TX = White
RX = Black

5 wire version "no manufacture stamp"
Com = Black & Shield
Audio = Yellow
TX = Red
RX = White
Bottom pic shows the made in Japan mic on the right and I noticed some mold design differences between the two.
Just wanted to document what I found so others wont pull their hair out trying to wire a simple Cobra stock and hopefully solve what may be a common issue caused by a design flaw.
View attachment 37885 View attachment 37884 View attachment 37883 View attachment 37886

How about that Texas Ranger branded mic? It came with a tr-296 and looks like a coffin mic. I never opened it up or had a cobra mic to compare it to. My guess it's made of fine Chineesium alloy.

 

[Tokin]

View attachment 37887

How about that Texas Ranger branded mic? It came with a tr-296 and looks like a coffin mic. I never opened it up or had a cobra mic to compare it to. My guess it's made of fine Chineesium alloy.

Here, hold my doobie...
On the LEFT is a coffin style mic named Colt and made in Japan.
In the MIDDLE is another coffin style mic named Texas Ranger and made in China.
On the LEFT is yet another coffin style mic named CB Microphone also made in China.
The TR and the CB Microphone looks a lot like the 5 wire cobra so im going to assume its also chinese made.
The Colt is interesting, it has larger wire gauge and has a somewhat different case design. A couple squirts of deoxit and it works like new. I miss Japanese manufacturing...

 

[Tokin]

Im also seeing a Thailand made cobra coffin mic. Ill buy one and open it up.
Update: I see a Taiwan one too...
Im finding a Japan made Cobra branded single screw like the Colt.
There seems to be many different Cobra coffin mics. Looks like im starting a new collection hahaha!
So far ive found:
2 made in Japan, one 3 screw which appears to be the more rare and a single screw which of the Japan made are much more abundant.
One made in Thailand and one made in Taiwan.
I would like to believe the Taiwan model to be the last of the quality Cobra branded coffin mics. Many chinese copies after that.
I need to try to research the mic element's...

 

[sunbulls]

Teaberry radios also used Japanese coffin mics, particularly the early 23ch models. If the cords are worn or bad on any of those Japanese mics, I never tossed them. Replacing the cord I feel is always worth the effort. The cord is usually replaced with the longer, thinner and more flexible type.

 

[Low_Boy]

The best? The one you like the most, that’s the best.
The most popular? With the trucking crowd it’s the Astatic 636L, especially if talkback has been added in.

The best sounding? That depends on who is talking on it, you might sound good on a 636L, I might not. And we both might sound the same but ole Joe might say differently while listening to us talk. It’s a matter of opinion.

I rarely see bad switches in mics but I certainly see a bunch of broken wires, especially at the plug. Like elements, very rarely have I seen one go bad, maybe 1 out of 100?

The best? The one you like the most, that’s the best.
The most popular? With the trucking crowd it’s the Astatic 636L, especially if talkback has been added in.

The best sounding? That depends on who is talking on it, you might sound good on a 636L, I might not. And we both might sound the same but ole Joe might say differently while listening to us talk. It’s a matter of opinion.

I rarely see bad switches in mics but I certainly see a bunch of broken wires, especially at the plug. Like elements, very rarely have I seen one go bad, maybe 1 out of 100?

X2

 

[Handy Andy]

I didn't know if you caught this...

​

Since you were mentioning Quality - I thought showing this might help others later when it comes to how the attention to small details somehow gets lost in subsequent generations...

Some of the makers of the mics' like you have above, used to apply the Elements GROUND or Return to the CENTER of the DPDT Pole that handled the Speaker to TX switch grounding.

They wired the ground of the mic to the same wire that was ground to the Speaker and the TX switching.

This reduced the problem of shielding as well as the "scratching" noise the wiper would make. The Element was soldered to the same Ground, so the only source of noise would be from the other pole and it's wiper action and any dirt in-between.

This level of thinking somehow never left their shores and the ones that took over simply followed letter by letter and post to post - of the schematic. They never thought to look inside or question the schematics references nor the assembly that you needed to pay attention to that showed the levels of quality assembly between generations and locations of manufacture. That is, the SAME Manufacturer.

Some even went as far as to use the Shield - tied the Elements Return to it, and simply let the DPDT poles handle the Ground to Speaker or to TX.

Several Midland Radios I've owned - required you to use the Limiter - because they placed both Element wires on their respective poles. so when the RX to TX switching occurs, the radios switching then killed the Limiter bias and opened up the Mic line.

Else you'd have a "squeal" or tone out of the radio from the Mic elements wire live with the Mic amp and without the limtier - the mic amp was active all the time - causing the squeal.

 

[Low_Boy]

The best? The one you like the most, that’s the best.
The most popular? With the trucking crowd it’s the Astatic 636L, especially if talkback has been added in.

The best sounding? That depends on who is talking on it, you might sound good on a 636L, I might not. And we both might sound the same but ole Joe might say differently while listening to us talk. It’s a matter of opinion.

I rarely see bad switches in mics but I certainly see a bunch of broken wires, especially at the plug. Like elements, very rarely have I seen one go bad, maybe 1 out of 100?

I second the 636L. Good sounding and they are loud with not a lot of background noise. Only problem if used mobile you will be replacing the cord in a year.

 

[oldtymer]

You stated radio was peaked & you did not want a power mic.
A lot of people I talk with locally use a Superstar stock mic available on Flea Bay for
a good price. They come pre-wired for different radios.
Sound pretty good on RCI, Cobra,& Uniden radios.

 

[Tokin]

I didn't know if you caught this...

View attachment 37913​

Since you were mentioning Quality - I thought showing this might help others later when it comes to how the attention to small details somehow gets lost in subsequent generations...

Some of the makers of the mics' like you have above, used to apply the Elements GROUND or Return to the CENTER of the DPDT Pole that handled the Speaker to TX switch grounding.

They wired the ground of the mic to the same wire that was ground to the Speaker and the TX switching.

This reduced the problem of shielding as well as the "scratching" noise the wiper would make. The Element was soldered to the same Ground, so the only source of noise would be from the other pole and it's wiper action and any dirt in-between.

This level of thinking somehow never left their shores and the ones that took over simply followed letter by letter and post to post - of the schematic. They never thought to look inside or question the schematics references nor the assembly that you needed to pay attention to that showed the levels of quality assembly between generations and locations of manufacture. That is, the SAME Manufacturer.

Some even went as far as to use the Shield - tied the Elements Return to it, and simply let the DPDT poles handle the Ground to Speaker or to TX.

Several Midland Radios I've owned - required you to use the Limiter - because they placed both Element wires on their respective poles. so when the RX to TX switching occurs, the radios switching then killed the Limiter bias and opened up the Mic line.

Else you'd have a "squeal" or tone out of the radio from the Mic elements wire live with the Mic amp and without the limtier - the mic amp was active all the time - causing the squeal.

Interesting, ive been having issues with a squeal when trying to pair the cobra coffins with my eq/29 combo. The chinese knock offs work great but the second i put a stock cobra coffin on it squeals...

 

[Tokin]

I like this t747 mic test station. Ive tested 20+
Mics and to be honest I dont hear much difference between the different Cobra coffins, chinese or not and the best sounding, cleanestic so far is the Diesel 4-3 Noise cancelling mic I have. A 636L chrome but like the cobra mics it squeals on my set up.
The only mics ive been able to use are the chinese but to be honest I get good audio reports from everyone. Right now I have a "Galaxy" branded chinese mic on it now.

 

[Handy Andy]

I think the "squeal" has more to do with Open Mike Night - that being they tie all of the Audio and TX ground to pin 1 - leaving Pin 4 floating somewhere - acts like a nice little antenna for RF...

But then, if you have Wi-Fi - Hi-Fi installed - the excessive capacitance usually rears it's ugly head and you'll have to shrink down a range of cap input to keep the Mic Amp stable - doesn't mean loss of fidelity - just the drive - you can compensate somewhat by adjusting resistance the Mic amp uses amongst the 3 pins it uses for the Mic's feedback - Power feed and EQ (offset Pin).


In the circuit above R164 sends power into Pin 3 to power this side of the Mic amp - it uses a 10K but the divider is a 12K - this places more "power" on the high side than to make it closer to Class A amp - you might want to "tweak these two resistors" to find your right balance of drive and "fidelity" for as it stands, the divider is not truly "balanced"

the best sounding, cleanestic so far is the Diesel 4-3 Noise cancelling mic I have.

Oh geez, Diesel 4-3?

Did some work on a 4-2 brother of his...

​

 

[144inBama]

I've been pleased with the RK56.....but honestly it's the only aftermarket mic I've ever used for any length of time on any of my radios.