The Microphone

Last year sometime W4PWB purchased a pair of condenser microphones from Musician's Friend for a reasonable price. They were 1/2 off at the time and he had some big plans for what to do with the studio microphone pair.

We like to play guitar and since he has some decent recording equipment we decided that we'd use one of the microphones solely for that purpose. The second would perhaps be for vocals or additional backup recording done at the same time while we laid track after track down on the digital recorder.

Shortly after receiving the MXL V63M condenser microphones we discovered that they required 48v of phantom power. This was definitely something that was a let down for both of us. Instead of sending the microphones back to Musician's Friend Phil decided that we would get the required phantom power from a PA amplifier that we'd been using for the electric guitar and other vocals going to yet another PA for final output. In short it worked great and we were on our way to having a stage presence. The recording software was installed into a laptop and although the input was horrible we did make some decent recordings using that method.

It was later decided that the use of an EQ was going to be needed to get a line level for the computers input and remove unwanted noises from the recording. We headed down to the local music shop, who is owned by the same people as Musician's Friend and he decided on a Mackie 402-VLZ3 mixer with EQ. We now had a pretty good setup going for recording the music we were playing.

Much discussion went on about using one of the microphones on his Yaesu FT-900. I was unsure about the whole phantom power issue and had heard a lot of issues about using condenser microphones on amateur radio. We had both read many articles of both delight and disgust with the different setups that people were using.

There is an impedance difference of 300 ohms, but that is easily overcome with a transformer. It has been my experience that such a small amount when it comes to audio isn't going to make an appreciable difference.

We'd played with digital SSTV for hours, moved to digipan, and then to CW. The night was starting to get stale but still to early for calling it quits. Then it hit me! The Mackie wasn't going to allow that 48v of phantom power to come back out the other side since it was just using it to drive the element preamplifier in the MXL V63M.

I quickly looked up the wiring diagram for the FT-900 and relayed the information back to Phil. He was reluctant at first, but sensing that what I was telling him was probably right he decided to give it a try. Gathering the items we were going to need to hook it up he came back to the radio. "I've got all the items we need, but are you sure this is going to work?". I told him yes, but we might not like the way it sounds.

The FT-900 has an 8 pin modular jack on the front of the radio. Pin 4 is positive mic and pin 5 is negative. I'm not sure what he used, but history tells me it was just a piece of Ethernet cable that only had a connector on one end of it. These are fairly well shielded and carry a signal better than you might think at first glance. Since this was a temporary hookup nothing was soldered and the entire thing was sort of pieced together just to test it out. After all, that is what we're supposed to do isn't it?

With all of the connections in place Phil began to test the microphone. Initially there was a huge buzzing sound heard on my end. After about 20 minutes of adjusting audio was being transmitted. Although adjustment of the VOX and other related settings seemed to be unlikely because of the wire Phil had strung all over the place, we still continued to word towards good clean audio.

It was not after 5am and Phil's house was starting to get moving to work and school. Even Phil had to get some sleep before getting up to work the late shift he had the following day. We'd spent so much time playing with other things that our time was short.