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Gear / Technical Help => Microphones & Setup => Topic started by: gazatthebop on November 19, 2020, 02:59:36 PM

Title: building a microphone 9v battery power supply for beginners
Post by: gazatthebop on November 19, 2020, 02:59:36 PM
https://www.church-audio.com/shop/battery-boxes/ugly-battery-box/ (https://www.church-audio.com/shop/battery-boxes/ugly-battery-box/)

Rather than spend money i don't have can anyone explain how to make one of these (CA11 9Vbattery power supply). It looks simple enough!
Title: Re: building a microphone 9v battery power supply for beginners
Post by: ycoop on November 19, 2020, 04:38:29 PM
This should help:

http://forums.sonyinsider.com/topic/14343-how-to-build-a-stereo-microphone-and-battery-box/
Title: Re: building a microphone 9v battery power supply for beginners
Post by: jerryfreak on November 19, 2020, 05:30:21 PM
depends on 2-wire or 3-wire mic of course, the latter being simpler. in general both require a voltage source,a current-limiting resistor, and a smoothing capacitor

a 2-wire design needs a decoupling capacitor in line
Title: Re: building a microphone 9v battery power supply for beginners
Post by: gazatthebop on November 20, 2020, 12:05:59 PM
thanks for replies
Title: Re: building a microphone 9v battery power supply for beginners
Post by: DavidPuddy on November 20, 2020, 12:49:24 PM
This should help:

http://forums.sonyinsider.com/topic/14343-how-to-build-a-stereo-microphone-and-battery-box/

This is great, thanks. I just ordered the parts from Digikey to build a few of these in altoids tins. I will be able to use my MKE2 mics again, finally...
Title: Re: building a microphone 9v battery power supply for beginners
Post by: DavidPuddy on November 30, 2020, 01:21:15 AM
I built the battery "box" from the Sony Insiders site tonight. If you have a soldering iron, you can build this easily. Just watch a few soldering technique videos on youtube to make sure you get a good mechanical/electrical connection or you'll be building this again.

Here's the parts I used:

2x RES 6.8K OHM 1/4W 1% AXIAL
2x CAP ALUM 1.5UF 20% 50V RADIAL
1x Battery Snap
1x 3.5mm Female Audio Jack - Stereo
1x Stripped 3.5mm Male Stereo Plug (from old cable)
1x Breadboard

However, I'm still getting 10.8v at the inputs, so it seems like the resistors are not lowering the voltage from the battery at all. Perhaps I should have used a higher value resistor. Sennheiser says the MKE2s (gopro hack) need ~7.5v, so if anyone knows if seeing the full 10.8v from the Powerex battery will cause problems, I'm all ears. I have some regular 9v rechargables in case i need to use those.

Anyway, I'll be attempting to mount it in an Altoids tin with some hot glue. I'll update with pics if anyone wants to see my admittedly amateur work.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: boa on November 30, 2020, 09:20:14 AM
I'd like to see pics. I am looking for a battery box. Thanks.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: robeti on November 30, 2020, 09:33:42 AM
https://www.church-audio.com/shop/battery-boxes/ugly-battery-box/ (https://www.church-audio.com/shop/battery-boxes/ugly-battery-box/)

Rather than spend money i don't have can anyone explain how to make one of these (CA11 9Vbattery power supply). It looks simple enough!

You don't have $36,- ?
Wow.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: jerryfreak on November 30, 2020, 09:51:11 AM
you can always switch from a 9.6V battery to an 8.4. has more mAh as well...

I built the battery "box" from the Sony Insiders site tonight.

Here's the parts I used:

2x RES 6.8K OHM 1/4W 1% AXIAL
2x CAP ALUM 1.5UF 20% 50V RADIAL
1x Battery Snap
1x 3.5mm Female Audio Jack - Stereo
1x Stripped 3.5mm Male Stereo Plug (from old cable)
1x Breadboard

However, I'm still getting 10.8v at the inputs, so it seems like the resistors are not lowering the voltage from the battery at all. Perhaps I should have used a higher value resistor. Sennheiser says the MKE2s (gopro hack) need ~7.5v, so if anyone knows if seeing the full 10.8v from the Powerex battery will cause problems, I'm all ears. I have some regular 9v rechargables in case i need to use those.

Anyway, I'll be attempting to mount it in an Altoids tin with some hot glue. I'll update with pics if anyone wants to see my admittedly amateur work.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: DavidPuddy on November 30, 2020, 10:37:45 AM
Here are the pictures. As you can see, there's not really much to this box and it looks like if you don't need any voltage attenuation, you can simply skip the resistors (unless i'm missing something to do with channel separation - please correct me if so). The altoids tin is probably 33% too big for this but it's easy to put together and common enough to not get a second look. I'm going to shrink wrap the ground connection and hot glue everything to the board as this board does not have pads to stabilize the components.

https://imgur.com/a/QnLToXM

https://imgur.com/PRS7wRt

https://imgur.com/uvUmr2x

https://imgur.com/SiOe1XQ

EDIT: Under load it looks like the voltage drop across the resistors is adequate. Measuring 10.8v from the battery (powerex 9.6v) and 8.2v at tip and ring. Running this on a Tenergy 9v gives the mics under 7.5v, so I'll use the Powerex for this application.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: kuba e on November 30, 2020, 03:34:06 PM
David, thanks for the pictures. The voltage drop across the resistor corresponds to the current  that flows to the microphone. The function of the resistor in 9V battery box is to limit the current. What I read here on the forum, the current is more important than the voltage of 9V. You could calculate the value of that resistor according to the parameters of a specific microphone (I am not able to do it). Or if you have chosen a value that others use, that will be fine.

Roberti, sometimes it's good to try to do it yourself, because you can learn something extra. Of course, there are cases where I blame myself for not giving it to a professional.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: DavidPuddy on November 30, 2020, 04:17:58 PM
https://www.church-audio.com/shop/battery-boxes/ugly-battery-box/ (https://www.church-audio.com/shop/battery-boxes/ugly-battery-box/)

Rather than spend money i don't have can anyone explain how to make one of these (CA11 9Vbattery power supply). It looks simple enough!

You don't have $36,- ?
Wow.

Some people prefer to build something that they can service themselves in the event of a failure...

David, thanks for the pictures. The voltage drop across the resistor corresponds to the current  that flows to the microphone. The function of the resistor in 9V battery box is to limit the current. What I read here on the forum, the current is more important than the voltage of 9V. You could calculate the value of that resistor according to the parameters of a specific microphone (I am not able to do it). Or if you have chosen a value that others use, that will be fine.


Thanks for the post. I bought a used intro to electronics textbook and will be slowly making my way through it.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: seethreepo on November 30, 2020, 07:11:47 PM
David, thanks for the pictures. The voltage drop across the resistor corresponds to the current  that flows to the microphone. The function of the resistor in 9V battery box is to limit the current. What I read here on the forum, the current is more important than the voltage of 9V. You could calculate the value of that resistor according to the parameters of a specific microphone (I am not able to do it). Or if you have chosen a value that others use, that will be fine.

Roberti, sometimes it's good to try to do it yourself, because you can learn something extra. Of course, there are cases where I blame myself for not giving it to a professional.

This 
Title: Re: building a microphone 9v battery power supply for beginners
Post by: seethreepo on November 30, 2020, 07:23:38 PM
I'd like to see pics. I am looking for a battery box. Thanks.

Check Yer PM's
Title: Re: building a microphone 9v battery power supply for beginners
Post by: goodcooker on December 02, 2020, 12:11:01 PM

I built a battery box years ago just to see if I could do it. It was kinda fun. The parts cost more than an already finished box but learning some simple circuit design and construction was beneficial. I'll see if I can find the schematic I used and some pics of the finished product.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: jerryfreak on December 02, 2020, 02:47:08 PM
David, thanks for the pictures. The voltage drop across the resistor corresponds to the current  that flows to the microphone. The function of the resistor in 9V battery box is to limit the current. What I read here on the forum, the current is more important than the voltage of 9V. You could calculate the value of that resistor according to the parameters of a specific microphone (I am not able to do it). Or if you have chosen a value that others use, that will be fine.

Roberti, sometimes it's good to try to do it yourself, because you can learn something extra. Of course, there are cases where I blame myself for not giving it to a professional.

This
This kind of made me think of an average fan saying to a taper with thousands of dollars of gear set up to tape, “Dude, you don’t have $15 to buy the soundboard?”
Title: Re: building a microphone 9v battery power supply for beginners
Post by: kuba e on December 02, 2020, 03:36:58 PM
 ;D

Yes, Robeti is right, sometimes our hobbies are very strange.