DIY Condenser Capsule noob question

...and how to do so...
jp008
KVRist
44 posts since 15 Oct, 2010

Post Sun Nov 03, 2019 5:06 am

What happens if I connect the two wires from a condenser capsule straight to an XLR plug and then plug it into a preamp with 48v phantom power ? Anything ? :ud: :hihi:

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thecontrolcentre
KVRAF
24973 posts since 27 Jul, 2005 from the wilds of wanny

Re: DIY Condenser Capsule noob question

Post Sun Nov 03, 2019 5:53 am

Try it and let us know if you survive.

jp008
KVRist
44 posts since 15 Oct, 2010

Re: DIY Condenser Capsule noob question

Post Sun Nov 03, 2019 6:20 am

thecontrolcentre wrote:
Sun Nov 03, 2019 5:53 am
Try it and let us know if you survive.
Seriously? Will it totally explode and start on fire ??

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vurt
addled muppet weed
53393 posts since 26 Jan, 2003 from through the looking glass

Re: DIY Condenser Capsule noob question

Post Sun Nov 03, 2019 6:22 am

you probably wouldn't feel it.
for long...

jp008
KVRist
44 posts since 15 Oct, 2010

Re: DIY Condenser Capsule noob question

Post Sun Nov 03, 2019 7:20 am

vurt wrote:
Sun Nov 03, 2019 6:22 am
you probably wouldn't feel it.
for long...
Alright, then what if I didn't apply phantom power. Would sound still come through the mic? How about just a 1.5v AA battery with a simple resistor or capacitor inline? No sound ?

jp008
KVRist
44 posts since 15 Oct, 2010

Re: DIY Condenser Capsule noob question

Post Sun Nov 03, 2019 9:39 am

I guess I'm just going to have to be dangerous and try to design my own microphone here ! Hopefully it doesn't explode. :cry:

Jim Y
KVRist
413 posts since 29 Jun, 2008 from Mid Wales, UK.

Re: DIY Condenser Capsule noob question

Post Sun Nov 03, 2019 10:07 am

Phantom power feeds the same voltage to hot and cold wires - with the same voltage on both wires, the capsule will do nothing. To use the power, you need to go from Hot or Cold to Ground
Standard P48 feeds out via 6.8k resistors, one each to hot and cold. If you connect the capsule between hot and ground, the capsule will work - for a short while but the current will be too high and the little JFET in the capsule won't like anything over 25v.
You can wire the capsule between the hot and cold wires and add a resistor from the cold to ground. IIRC, the resistor is about 33k. It pulls the cold voltage down just enough to get a working DC bias across the capsule.
Although it works, the capsule isn't grounded and will probably need a metal mesh shield to keep interference noise down,
Most Electret capsules are happy if you have about 2 to 3v DC bias on them (measure across the terminals) and the maximum is about 10v.

jp008
KVRist
44 posts since 15 Oct, 2010

Re: DIY Condenser Capsule noob question

Post Sun Nov 03, 2019 12:17 pm

Jim Y wrote:
Sun Nov 03, 2019 10:07 am
You can wire the capsule between the hot and cold wires and add a resistor from the cold to ground. IIRC, the resistor is about 33k. It pulls the cold voltage down just enough to get a working DC bias across the capsule.
Although it works, the capsule isn't grounded and will probably need a metal mesh shield to keep interference noise down,
Thanks for the info. The second option with the 33k resistor sounds interesting, but which wires would go to pins 2 and 3 on an XLR if both the hot/cold wires have the resistor between them?

jp008
KVRist
44 posts since 15 Oct, 2010

Re: DIY Condenser Capsule noob question

Post Mon Nov 04, 2019 1:03 am

.

I should add that the only reason I asked about this is I'm looking for a really easy way to simply use a condenser capsule. Not looking for anything elaborate or fancy and low output isn't an issue either, since I have a stepped preamp that can put out more than 80db of gain. I mean, how hard is it to also add an easy way to reduce noise? These type of things can't be that hard to design.. A. Fewest amount of parts.. B. Make it pass audio and C. Reduce the noise. How hard is that to achieve with a condenser capsule?

Anyone want to create a simple custom design for me? If it works at least half-assed, I would even publicly promote your design and name for my musical group. I will put it on my band page and promote it on video as well ! It would be used strictly for metal vocals.

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