Topic: 4.7 Mod Question

[obsidian]

I have used the "search" feature and I couldn't find the answer (I may have overlooked it), so I apologize for starting another topic/thread ...

My Son and I are attempting to make some very amature mics, one of those Father & Son projects, and I have stumbled across some diagrams to add the 4.7k but all I see are for 3 wire mics. Is this possible for a 2 wire mic? If not the 4.7, is there an alternative for a 2-wire mic?  Lastly, where do I find the little resistors and is their one brand any better than the other?

[beatkilla]

While i am no expert i'm pretty sure it is for 3 wire mics only.

[kuba e]

4.7k mod is for 3-wire mics for sure. What capsule do you want to use? I don't know alternative for 2-wire mics except modifying inner electronics inside capsule.  There is possibility to modify 2-wire capsule to 3-wire too (e.g. chopped Naks, Panasonic WM-61A). But you need good soldering skills. See https://www.youtube.com/watch?v=dSPQf42JgbI.

If you use 2-wire capsule, power it with maximal designed voltage. Microphone's maximal SPL stated in datasheet is valid only with maximal designed power. If you use lower voltage, the maximal SPL is lower too.

[obsidian]

These are the caps I intended to use. They do offer a 3-wire version, but I wasn't sure how hard that would be. Like I mentioned, this is just a project for me and my Son. We want it to be successful but not put a ton of money into it "to learn".  Is wiring a 3-wire caps much harder than a 2-wire?

http://micbooster.com/primo-microphone-capsules/133-primo-em184-cardioid-capsule-with-wires.html#/35-matched_capsules-2_matched

[kuba e]

I think the best is to buy caps with already soldered wires. Because soldering wires to cap is difficult. You must be careful, there is risk that you will fry the electronic (FET) inside the capsule . I looked in the datasheet of EM184 and it's max. SPL is 122 db, perhaps it is sufficient for our normal use.

I see on their webpage only two wire caps, one exception is EM173. If you choose EM173, you can try some adjustment on it to improve max. SPL. But if you will record quite sounds/music, adjustment are useless.

[obsidian]

I think the best is to buy caps with already soldered wires. Because soldering wires to cap is difficult. You must be careful, there is risk that you will fry the electronic (FET) inside the capsule . I looked in the datasheet of EM184 and it's max. SPL is 122 db, perhaps it is sufficient for our normal use.

I see on their webpage only two wire caps, one exception is EM173. If you choose EM173, you can try some adjustment on it to improve max. SPL. But if you will record quite sounds/music, adjustment are useless.

I agree completely. I was planning on ordering the matched caps that already have the soldered wires to (hopefully) avoid frying them. I think I will contact them about the 3-wire cap with the soldered leads already. I'm excited about this, I know people might think it's dumb but we (my Son and I) have had a blast looking up all this and we are really into doing it. Thanks for your help.

[kuba e]

I have Primo mics too. I am using Primo EM172 for recording lectures. I choose EM172 (the same as EM173) because it has lower Noise/Signal ration compared to other caps. It has omni pattern. If the arragment of lecture allows it, I will try it as boundary mics too. For music I am using Naks or Chris Church mics.

I understand you, it is nice to make your own mic. It is good experience, I made the same.

I think I will contact them about the 3-wire cap with the soldered leads already.

I am not electrician, I understand only basic theory. When you will speak with seller, ask what all kind of connection you can do with EM173. Let them confirm the following. The first, what values of resistor between source and ground you can choose.  Resistor has influence on mics sensitivity and SPL. The second,  you can use it with 2 or 3-wire battery box. If you have 2-wire battery box, whether you could connect the mic in Linkwitz connection for 2-wire, and icrease max SPL. (http://www.mp3forkidz.com/mic/mod.html).

[goodcooker]

I'm excited about this, I know people might think it's dumb but we (my Son and I) have had a blast looking up all this and we are really into doing it.

Not necessarily - I did the same thing many years back. I built a pair of omnis on a short extension that I could plug right into my recorder instead of using the internals and then built a battery box to go with them. It cost more in parts and time than if I had just bought something from Sound Pros but it was really fun and was a learning experience. At the time I was getting really handy and building my own mic cables and interconnects and also built a few homebrew mic mounts from PVC.