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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.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: ycoop on April 19, 2021, 01:38:11 AM
So I finally got things together and tried putting this together. I can get power to the mics and have them send a signal, but there’s absolutely so channel separation. I bought the capacitors and resistors a while back but remember trying to follow the guidance from that Sony insider post.

Attaching a picture of what I’ve got.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: DavidPuddy on April 19, 2021, 08:28:44 AM
So I finally got things together and tried putting this together. I can get power to the mics and have them send a signal, but there’s absolutely so channel separation. I bought the capacitors and resistors a while back but remember trying to follow the guidance from that Sony insider post.

Attaching a picture of what I’ve got.

Wow those caps are huge  :o

Channel separation issue should be resistor related. What values are you using? Can you give the voltage reading at the input jack terminals?

It looks like you're missing the ground connection from input to output. Otherwise it looks ok as long as your caps are wired in the correct orientation (can't tell from this picture)
Title: Re: building a microphone 9v battery power supply for beginners
Post by: ycoop on April 19, 2021, 01:47:12 PM
So I finally got things together and tried putting this together. I can get power to the mics and have them send a signal, but there’s absolutely so channel separation. I bought the capacitors and resistors a while back but remember trying to follow the guidance from that Sony insider post.

Attaching a picture of what I’ve got.

Wow those caps are huge  :o

Channel separation issue should be resistor related. What values are you using? Can you give the voltage reading at the input jack terminals?

It looks like you're missing the ground connection from input to output. Otherwise it looks ok as long as your caps are wired in the correct orientation (can't tell from this picture)

The resistors are 5.6k ohm. The capacitors are non-polarized (which I think is why they’re so big) so they shouldn’t need a specific orientation.
Are you saying I need to connect the ground on the input jack to the ground on the output jack? Does that also require a capacitor?

Also a side note, the signal from this battery box seemed to be very clean. I was surprised how minimal the noise seemed on my initial tests.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: DavidPuddy on April 19, 2021, 02:32:30 PM
So I finally got things together and tried putting this together. I can get power to the mics and have them send a signal, but there’s absolutely so channel separation. I bought the capacitors and resistors a while back but remember trying to follow the guidance from that Sony insider post.

Attaching a picture of what I’ve got.

Wow those caps are huge  :o

Channel separation issue should be resistor related. What values are you using? Can you give the voltage reading at the input jack terminals?

It looks like you're missing the ground connection from input to output. Otherwise it looks ok as long as your caps are wired in the correct orientation (can't tell from this picture)

The resistors are 5.6k ohm. The capacitors are non-polarized (which I think is why they’re so big) so they shouldn’t need a specific orientation.
Are you saying I need to connect the ground on the input jack to the ground on the output jack? Does that also require a capacitor?

Also a side note, the signal from this battery box seemed to be very clean. I was surprised how minimal the noise seemed on my initial tests.

No capacitor needed for the ground, you just need to connect the black wire coming from the battery to the ground lugs on both jacks. See my picture below:

https://imgur.com/a/QnLToXM
Title: Re: building a microphone 9v battery power supply for beginners
Post by: illconditioned on April 19, 2021, 03:17:23 PM
So I finally got things together and tried putting this together. I can get power to the mics and have them send a signal, but there’s absolutely so channel separation. I bought the capacitors and resistors a while back but remember trying to follow the guidance from that Sony insider post.

Attaching a picture of what I’ve got.
That is excellent.
I love the point-to-point wiring.
What now?  carefully insulate parts, or put it in hotmelt glue ?
Either way, glad to see the hacking....
Title: Re: building a microphone 9v battery power supply for beginners
Post by: ycoop on April 19, 2021, 09:47:12 PM
The lack of ground for the output side was the issue. Grounded that lug and the channels are now separate. I’ll bring t in to work tomorrow and take a reading of the voltage at the input jack. To do that would I be able to plug in a 3.5mm cable to the mic input jack and take the reading from either channel to ground?

My next step is to make holes in either side of a plastic housing I purchased, align the jacks with the holes and fill with hot melt glue.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: illconditioned on April 19, 2021, 11:51:04 PM
The lack of ground for the output side was the issue. Grounded that lug and the channels are now separate. I’ll bring t in to work tomorrow and take a reading of the voltage at the input jack. To do that would I be able to plug in a 3.5mm cable to the mic input jack and take the reading from either channel to ground?

My next step is to make holes in either side of a plastic housing I purchased, align the jacks with the holes and fill with hot melt glue.
Tip, from someone well versed in the use of hot melt glue.
You can glue in a few places only, to secure components inside the case, then cover with tape or cardboard.If you ever need to fix gear later on, it is great to have access.
If you don't want access, epoxy can be used.  That is what Chris used I think.  Two part epoxy.

Please post pics of finished product :)
  Richard
Title: Re: building a microphone 9v battery power supply for beginners
Post by: ycoop on April 20, 2021, 06:33:33 PM
So I finally got things together and tried putting this together. I can get power to the mics and have them send a signal, but there’s absolutely so channel separation. I bought the capacitors and resistors a while back but remember trying to follow the guidance from that Sony insider post.

Attaching a picture of what I’ve got.

Wow those caps are huge  :o

Channel separation issue should be resistor related. What values are you using? Can you give the voltage reading at the input jack terminals?

It looks like you're missing the ground connection from input to output. Otherwise it looks ok as long as your caps are wired in the correct orientation (can't tell from this picture)

Voltage reads 8.7 V
Title: Re: building a microphone 9v battery power supply for beginners
Post by: ycoop on April 20, 2021, 11:48:35 PM
Must have weakened a loose connection when I was setting the glue as the box now doesn't pass a signal.

Going to start from scratch with new components from digikey as opposed to the local electronics supply shop. Going to go with mounted jacks and housing with a battery compartment. Will update once everything arrives and is assembled.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: jerryfreak on April 21, 2021, 02:12:18 AM
no substitute for doing... the only way to learn!
Title: Re: building a microphone 9v battery power supply for beginners
Post by: illconditioned on April 21, 2021, 02:36:32 AM
Must have weakened a loose connection when I was setting the glue as the box now doesn't pass a signal.

Going to start from scratch with new components from digikey as opposed to the local electronics supply shop. Going to go with mounted jacks and housing with a battery compartment. Will update once everything arrives and is assembled.
Before you start over...
Look for "cold solder" joints.  Easy to detect by wiggling the wires and see where the break is.
Can you get hot melt glue away or have you completely encased the circuit?
Title: Re: building a microphone 9v battery power supply for beginners
Post by: ycoop on April 21, 2021, 12:35:28 PM
Must have weakened a loose connection when I was setting the glue as the box now doesn't pass a signal.

Going to start from scratch with new components from digikey as opposed to the local electronics supply shop. Going to go with mounted jacks and housing with a battery compartment. Will update once everything arrives and is assembled.
Before you start over...
Look for "cold solder" joints.  Easy to detect by wiggling the wires and see where the break is.
Can you get hot melt glue away or have you completely encased the circuit?

Circuit is completely encased. TBH I welcome the opportunity to force myself to do it from scratch.
Title: Re: building a microphone 9v battery power supply for beginners
Post by: illconditioned on April 21, 2021, 03:11:47 PM
Must have weakened a loose connection when I was setting the glue as the box now doesn't pass a signal.

Going to start from scratch with new components from digikey as opposed to the local electronics supply shop. Going to go with mounted jacks and housing with a battery compartment. Will update once everything arrives and is assembled.
Before you start over...
Look for "cold solder" joints.  Easy to detect by wiggling the wires and see where the break is.
Can you get hot melt glue away or have you completely encased the circuit?

Circuit is completely encased. TBH I welcome the opportunity to force myself to do it from scratch.
LOLZ
Welcome to the club.
Nothing wrong with point to point wiring though.  It is the best.