Aloha Guys, New to the forum and havent had the opertunity to get my ticket for HAM. But I wanna upgrade my audio on my Cobra 146GTL base station..Im currently running a Silver Eagel Pwr Mic. I got a Nandy RMX-6 mixer here that I wanna use.
Just want to know how do I hook it up to my radio like wiring it to the radio. What pin goes where into the 4 pin mic plug. Do I use a studio mic or any XLR mic. Im planning to use ither the XLR output or the Phono jack to transfer the audio to my radio.
I heard some ofmy friends running a Bheringer or some kind of a mixer on SSB and AM 11M, sounds pretty awesome. Just wanna play w/this Nandy here see what I can do w/it.
New to Voodoo!!! ???Nandy RMX Mixer Install!!!
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15MINIGRASS
- Audio Head
- Posts: 3
- Joined: Sat Aug 07, 2010 2:19 pm
Aloha, Minigrass:
I considered doing that with my CB at one time. That is - get a real mic and hook it up to a CB with a Behringer, Nady, or some other brand of mic preamp. But then - I got my Ham ticket a couple of years back, and never thought about doing it since then.
The problem with many CB radios is that they don't have enough filter width built into them to allow for a real wide hifi sound on SSB. The are just too narrow on SSB, which keeps them sounding a bit 'nasal' or 'pinched' sounding at best. Even with some great mics or preamps; it is like trying to push a 5 foot wide/500-pound man thru a 2 1/2 foot wide doorway - the door is just too narrow for the wide guy to get in. Only a part of him will ever get through/in that doorway. It will still sound MUCH better; but one cannot expect 'True ESSB' hifi sound from it. Some of the guys you might be hearing on CB SSB using hifi audio aren't using radios like a Cobra. Many Hams using "ESSB' are using certain models of radios - like Kenwood, Elecraft, Flexradio, Icom, and Yaesu. Not even all of those radios can do ESSB; only some can - and some need to be modified as well. Mostly Kenwood are chosen - which can be as wide as 6khz on SSB!
What will happen with a CB radio on SSB, is that much of the bass and highs sound will get clipped out of the transmitted sound.
But AM is different...
You can get the AM to sound hifi with a CB; because it is twice as wide as either USB or LSB is. (But the best part of CB radio -to me- was using SSB/27.385 LSB!) Most CB radios are 2.5khz wide on SSB; and most hifi SSB that you hear is ~5khz wide. But the same CB radio you have will be capable of a 5khz width in AM mode! It is legal to do on AM/CB as well because the filters will cut it off and not allow it to exceed bandwidth. Provided that you do not exceed 100% modulation - of course! What you will have is audio that is potentially much better than a stock Cobra mic - by a far cry! The quality of the mic will define what you get. A better mic is sure to help considerably.
If you are going to do this hifi thing on AM/CB; then you will have to wire the mic audio pin and ground pin from the radio to the output of the mic preamp. You may need to include an audio transformer to convert a 'balanced output' (the mic preamp is a balanced output) to the 'unbalanced' input of the radio. Without the transformer, it might get some unwanted 'hum' in the transmit. Then you have to find the PTT +/- pins on the radio and use either a foot switch or a hand switch wired to close that contact. And therefore complete the PTT circuit in order to TX. The mic cable to the mic preamp should be a 3 pin XLR connector. You might find that the cost of a nice mic preamp and a nice mic is probably worth more than the Cobra 148GTL. You could get a cheap ~$30 tube mic preamp from a music store and find a nice used condenser mic from the same place for ~$75, and wire it all up yourself with another ~$30. A transformer can be cheap or very expensive - depending on what type and brand you choose.
If you have the mic preamp too high going into the radio; you might fry a transistor or even the audio chip itself. Find a local tech to help you work out the details if you want to do it right the first time and not damage your radio.
Mahalo Aloha!
I considered doing that with my CB at one time. That is - get a real mic and hook it up to a CB with a Behringer, Nady, or some other brand of mic preamp. But then - I got my Ham ticket a couple of years back, and never thought about doing it since then.
The problem with many CB radios is that they don't have enough filter width built into them to allow for a real wide hifi sound on SSB. The are just too narrow on SSB, which keeps them sounding a bit 'nasal' or 'pinched' sounding at best. Even with some great mics or preamps; it is like trying to push a 5 foot wide/500-pound man thru a 2 1/2 foot wide doorway - the door is just too narrow for the wide guy to get in. Only a part of him will ever get through/in that doorway. It will still sound MUCH better; but one cannot expect 'True ESSB' hifi sound from it. Some of the guys you might be hearing on CB SSB using hifi audio aren't using radios like a Cobra. Many Hams using "ESSB' are using certain models of radios - like Kenwood, Elecraft, Flexradio, Icom, and Yaesu. Not even all of those radios can do ESSB; only some can - and some need to be modified as well. Mostly Kenwood are chosen - which can be as wide as 6khz on SSB!
What will happen with a CB radio on SSB, is that much of the bass and highs sound will get clipped out of the transmitted sound.
But AM is different...
You can get the AM to sound hifi with a CB; because it is twice as wide as either USB or LSB is. (But the best part of CB radio -to me- was using SSB/27.385 LSB!) Most CB radios are 2.5khz wide on SSB; and most hifi SSB that you hear is ~5khz wide. But the same CB radio you have will be capable of a 5khz width in AM mode! It is legal to do on AM/CB as well because the filters will cut it off and not allow it to exceed bandwidth. Provided that you do not exceed 100% modulation - of course! What you will have is audio that is potentially much better than a stock Cobra mic - by a far cry! The quality of the mic will define what you get. A better mic is sure to help considerably.
If you are going to do this hifi thing on AM/CB; then you will have to wire the mic audio pin and ground pin from the radio to the output of the mic preamp. You may need to include an audio transformer to convert a 'balanced output' (the mic preamp is a balanced output) to the 'unbalanced' input of the radio. Without the transformer, it might get some unwanted 'hum' in the transmit. Then you have to find the PTT +/- pins on the radio and use either a foot switch or a hand switch wired to close that contact. And therefore complete the PTT circuit in order to TX. The mic cable to the mic preamp should be a 3 pin XLR connector. You might find that the cost of a nice mic preamp and a nice mic is probably worth more than the Cobra 148GTL. You could get a cheap ~$30 tube mic preamp from a music store and find a nice used condenser mic from the same place for ~$75, and wire it all up yourself with another ~$30. A transformer can be cheap or very expensive - depending on what type and brand you choose.
If you have the mic preamp too high going into the radio; you might fry a transistor or even the audio chip itself. Find a local tech to help you work out the details if you want to do it right the first time and not damage your radio.
Mahalo Aloha!
Last edited by SawzAll on Sun Aug 08, 2010 12:21 am, edited 4 times in total.
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15MINIGRASS
- Audio Head
- Posts: 3
- Joined: Sat Aug 07, 2010 2:19 pm
And yes one of the guys I heard w/great audio was using an HF Rig. Didn't know all that was included in a HI def audio. -
15MINIGRASS
- Audio Head
- Posts: 3
- Joined: Sat Aug 07, 2010 2:19 pm
Sorry been a long ti,e I didi manage to get it to work I got the hum out but feedback was a pain. Is a direct box goood to make a balanced to unbalaced line into my radio?
The output from my Nandy mixer is phono but here is also a XLR output. I think I can connect a transformer inline with the XLR output then to the phono to my shield and audio on the mic pins. I was using a stock cb mic then connecting the shield and audio connecting to the internal mic elemenet of the cb mic.
Any sugestions. My friend is also running a bheringer mixer, his music comes out clean on the recieving end but the channel with the mic that he talks on sounds muffled. any idea why? Heres a short gate.
Aloha James. Saw it is a Nandt RMX 6 rack gear/
The output from my Nandy mixer is phono but here is also a XLR output. I think I can connect a transformer inline with the XLR output then to the phono to my shield and audio on the mic pins. I was using a stock cb mic then connecting the shield and audio connecting to the internal mic elemenet of the cb mic.
Any sugestions. My friend is also running a bheringer mixer, his music comes out clean on the recieving end but the channel with the mic that he talks on sounds muffled. any idea why? Heres a short gate.
Aloha James. Saw it is a Nandt RMX 6 rack gear/