Electro-Voice 602T noise cancelling microphone

The 602 had four elements in them, the F version is a noise canceling directional element with a 5k top end and a 2000 hz top end noise canceling capabilities. The FL is a emi/rfi element to prevent interference from radio and is like the F version. The T version if I remember right is the noise canceling directional mic element with 5k top end response which has noise canceling below 1500 hz. The E/EL version are omni-directional elements with a 7k top end response and above 2000 hz noise canceling - this is more common in PA systems.

The M109 is like a 602 but is more or less a NSN designation.

The 602 series high impedance mic usually has the three wire cable while the low impedance has the four wire cable. There is a catch, MOST of those four wire cables are double shield audio cables and do not have the common ground (need to be rewired) that the common poorly design CB has. IF at all possible, you could use the four wire double shield mic cord, do so but that would mean actually modifying the radio.

I don't get the tuning of the radio that would make it sound better. The audio strip is set until it is injected into the RF, so tuning may not matter. Modifying the audio strip would be a better choice but that's me.

 

This goes for all of them.

You may think you have every version but I bet you don't have a G or LH model. I know you don't have a VR model. They produced something like 70 different types of mics based on the same engineering.

No there are elements that are in the 200 ohm range. What Telex/EV/Turner/ETC. ... did in the past was obsolete models and parts, superseding them to another model. In the case of elements, they would produce a production run of an element for one model and add to the number for estimated replacement parts. SO to explain it if they made 25,000 mics, they would estimate through past parts sales to see what number of elements they would need to have in inventory to service those mics. So say they made 25,000 then they would need 1500 elements in inventory for replacement parts for that mic production run. When they ran out, they would use a newer element as a replacement.

Each mic has a different characteristic to it, so as I said there are some with a 5k top end response and others with a 7k.

That may be true I don't know. I abhor the way these CBs are switched, it is a poor and cheap design. The old simple three wire switching or three wire switching with balanced audio was much much better.

 

Well that's the problem with these radios, poor design.

However, if you don't understand why your d58 has a lower level, then you need to learn a thing or two about mics and impedence. Your point of a transformer goes away with the understanding how they work, the difference between balanced and unbalanced (that is what the low impedence ev mics are setup to be) and how to actually get good audio out of a radio.

By the way, the d58 is an ok mic, it isn't the best or worst of the mic world, I would not use it. Just because it is a paging mic, does not mean that it is an effective one. I have used on my am gear one of a few mics, the best is a $1.59 mic that replaced my heil disaster. The other ones range from a broadcast RCA 44a to a Marconi 46ex.

 

I opened up my oldest Telex RK56 from my collection and this is what I found inside. I had the switch replaced about 8 yrs or so ago cause the spring had broke.

 

Inside look of my SRA 198