wire a Shure 577B mic

My ranger SRA 198 out performs my RK 56 which are the originals from "Nebraska", so makes me wonder how much better they are built. I don't plan on cutting my 2 " 56's" loose anytime soon either. But now I'm on a quest to conquer a EV602F. What puzzles me though the modification to be done on them to make them work outstanding on my Galaxy Pluto radio.

 

I know a couple guys that bought them from barjunk, I'm gonna ask them if they let me open one up.

 

That would definitely solve a mystery. I know the company that made the original Transformer is no longer in business and that when Telex sold Turner to DAS they sold the complete inventory of parts to build the Road King microphone so the first batch of microphones that came from DAS had genuine American made parts in them until their inventory ran out probably within the first few months.

 

I bid on a EV 602F last night for $35.00 and the seller has to pay the shipping, I'm still waiting for a reply. Also I did some research on the CR577, it looks like its a power mic with a battery in it. I'm done with Mic's with a battery in them. I had my fair share with them 30 years ago, had a Turner 76 I believe, battery wouldn't last squat. My Galaxy Pluto has a RFX75 behind it, had to replace the stock finals so I just had them replace with a little more kick. Now back to the EV602F mic, if I do pick one up, what will need to be done to make it work on export radio (Galaxy Pluto)? I read on this thread that besides eliminating certain thing in the mic, they had modify them with putting something else from a RK56. Did I read it correctly ?

 

1 shield
2 audio
3 transmit
Only 3 wires for your radio

 

I can guide you through the process whenever you get it taken apart in front of you

 

OK, thanks. I'm still waiting for a reply from the seller. I will let you know on the outcome.

 

Who tuned the radio? How your Road King performs is going to be determined by who tuned the radio. Different technicians do different things to radios and the same microphone will perform 10 different ways on the same radio tuned by 10 different technicians.

 

On a stock unmodified Radio fresh out of the box the original RK56 generally provides louder audio and perfect clarity than an Astatic 661 or whatever it is called. And the reason for this is the impedance mismatch between the 150 ohm element of the Astatic microphone and the 600 ohm input of the radio. The RK56 has an element almost identical to the other brand, but the advantage is the 4 to 1 step up transformer which matches the impedance perfectly to the input of the radio. It also has a .1 microfarad capacitor in line with the audio wire which acts as a high pass filter which increases the efficiency of the transmitter. It chops off a little of your bass and it might sound a little higher pitched but higher frequencies travel further than lower frequencies. I'm not sure if you've ever noticed a man and a woman driving in a truck talking on the same radio and the woman's voice carries a lot further than her husband's voice on the same radio. It's a similar principle.

 

C.B. radio shop in Ontario down the street from the T.A. has always done my work. The RK 56 I had for over 30 years has been flawless except for the spring on the key(wear and rear). When I bought the SRA 198, I switch it back and forth with the 56 and ask the other drivers for the opinions and which if the two sounded better and all said hands down on the SRA 198. I did this while driving down the road. They have always said to me the RK 56 was a good sounding mic before I bought the 198, but it improve it better. I'm also running the old Wilson 1000 which I had for 25 years.