Now we are preparing to build a mic from scratch, pretty much, using the MP-V57 PCB KIT also from Microphone-parts.com. For a donor mic we have two options:
1. An MXL-910 that we picked up on Ebay for $40
2. A BM700 cheapo Chinese microphone
The MXL 910 we may save for either a second MP-V57 kit or for a customer Ribbon Microphone build.
The BM700 is smaller than the MXL 910 with a shorter head basket which presents issues. When I got the BM700 I did a capsule test fit of sorts and found the basket was too short by about two millimeters or so. It also does not have a normal platform for attaching a capsule mount either.
In order to mount a capsule into the BM700 I removed the post from the mount and shaved off the rubber. This allowed the capsule to fit without touching the top inside of the basket. I also had to shave down the outside of the capsule so that it would fit into the basket. On top of that I had to also glue the mount to the platform because none of the mounting holes matched.
There is a BM800 out there on Ebay which is similar to the BM700 but with a different style head basket that is more like the MXL 910 in that it's a barrel shape and looks to be a little taller. My reservations about the BM800 is that it's the same as the BM700 but with a taller head basket. It probably has the same platform as the 700 which means you should stay away from the 800. Currently I am looking for a cheap alternative in China.
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We ended up using the MXL 910 as the donor. The circuit boards from the MP-V57 kit fit it perfectly and it sounds great.
It helps to organize the parts. I laid them all out on a sheet of card stock which was very helpful. I pretty much lad them out as shown in the manual which is very well written.
There was a couple issues to deal with which were all human error. One was the fact I installed the JFET backwards even though I was certain I was putting everything in the right positions. Luckily I was able to solder suck that part and turn it around. The other was the small switch. That switch has to be handled very carefully because the leads are easy to break. I made the mistake of bending two of the leads up to get them out of the way and when I bent them back down they snapped, leaving nothing to solder to.
Matt at microphone-parts.com was fantastic and for $5 he shipped me a new switch which I installed and then finished the assembly and adjustment.
Let me tell you, if you have a Multimeter like mine that does not have clips on the ends of the leads be sure and get them.. It will make it much easier to adjust the power setting. With clips you can adust real time but I had the needle-like ends on mine and it was a matter of turn the pot and test and repeat. A multimeter is a must have for this build, you cannot complete the kit without it.
I painted our MXL 910 because it is no longer a MXL 910. All of the guts of the original microphone are gone leaving only the body of the mic.
Capsule - We ended up going with a AK47 capsule from Advanced Audio Microphones in Canada. Now that microphone-parts.com has a complete kit I would do that in the future. $259 for the body, boards and components with a capsule is a great deal. We paid a total of $279 for our microphone when all was said and done with the MP-V57 kit, the AK47 capsule, the donor mic, the replacement switch and paint.
Below are pictures of the microphone and parts.
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| MPV57 Circuit Boards |
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| MP-V57 Circuit Boards |
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| MP-V57 Circuit Boards with parts |
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| MP-V57 Kit Assembled |
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| MP-V57 and MXL 910 Body - Note the hole for access to the switch. |
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| MP-V57/MXL 910 Repainted and on the mic stand. |
