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Author Topic: Countryman B3 modification question  (Read 497 times)

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Offline one8ung

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Countryman B3 modification question
« on: November 01, 2022, 12:37:17 PM »
There was recently offered me two separate Countryman B3 Omni Lavalier Mics (B3W5FF05LNC) with a Lemo1 plug.

I want to make a stereo pair out of them and terminates into a 1/8" jack and power them with a ca-ugly battery box.

Question: do i need to make a 4.7k modification and if yes, how can i do that myself?

Think they are "Low Sens" microphones...

Thanks for any help!
« Last Edit: November 01, 2022, 12:49:36 PM by one8ung »
Mics: Countryman B3 - DPA 4061 - OKM II

Power: A3 Adapter - CA-UBB

Recorders: Tascam DR-2d (3x)

Offline Gutbucket

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Re: Countryman B3 modification question
« Reply #1 on: November 01, 2022, 02:57:47 PM »
Plenty of folks use them wired directly to a 3.5mm (1/8") stereo plug.  However, Richard stated the following in an older TS thread about them-

You need a source resistor - between black wire and ground, one for each channel.

I use a 2.2k sometimes, for moderately loud stuff.  This works with both plug-in-power and a battery box.  For absolute certainly, use a 4.7k resistor, but in that case, you'll probably want a 9v battery box (or preamp) instead of plug-in-power.

  Richard

[snip..] I'm definitely planning to record some really loud shows in the future. There isn't really any benefit to powering the B3s with 9v without the resistors, is there?
OK, you should have 4.7k in there at all times.  For quiet shows (or ambient stuff) use Plug-in-power.  For loud shows use a regular (2-wire) battery box.

  Richard
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline one8ung

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Re: Countryman B3 modification question
« Reply #2 on: November 01, 2022, 09:36:41 PM »
Thanks...

Which Resistors can i best use, a Carbon Film or Metal Film Resistors.

And what about the tolerance?
« Last Edit: November 02, 2022, 01:47:39 AM by one8ung »
Mics: Countryman B3 - DPA 4061 - OKM II

Power: A3 Adapter - CA-UBB

Recorders: Tascam DR-2d (3x)

Offline Gutbucket

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Re: Countryman B3 modification question
« Reply #3 on: November 02, 2022, 08:54:23 AM »
I'm not sure the answer to either. But I don't expect tight tolerance to be critical.
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline commongrounder

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Re: Countryman B3 modification question
« Reply #4 on: November 02, 2022, 10:27:31 AM »
Thanks...

Which Resistors can i best use, a Carbon Film or Metal Film Resistors.

And what about the tolerance?

Metal film resistors have the lowest self thermal noise, and are preferred for audio signal paths. The tolerance doesn’t matter in this application. Metal film has inherently tight tolerances anyway.

Offline kuba e

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Re: Countryman B3 modification question
« Reply #5 on: November 02, 2022, 02:40:18 PM »
I think two resistors that have the same value should be used. I read somewhere that you should buy multiple resistors and then choose the pair that is the closest to each other. But I could be wrong,  I have no experience with this.

Offline illconditioned

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Re: Countryman B3 modification question
« Reply #6 on: November 02, 2022, 08:18:34 PM »
Plenty of folks use them wired directly to a 3.5mm (1/8") stereo plug.  However, Richard stated the following in an older TS thread about them-

You need a source resistor - between black wire and ground, one for each channel.

I use a 2.2k sometimes, for moderately loud stuff.  This works with both plug-in-power and a battery box.  For absolute certainly, use a 4.7k resistor, but in that case, you'll probably want a 9v battery box (or preamp) instead of plug-in-power.

  Richard

[snip..] I'm definitely planning to record some really loud shows in the future. There isn't really any benefit to powering the B3s with 9v without the resistors, is there?
OK, you should have 4.7k in there at all times.  For quiet shows (or ambient stuff) use Plug-in-power.  For loud shows use a regular (2-wire) battery box.

  Richard
Have you got a multimeter?  Measure resistance from both wires to ground (shield).  I think one is already grounded and mods are not needed.
Please DO NOT mail me with tech questions.  I will try to answer in the forums when I get a chance.  Thanks.

Sample recordings at: http://www.soundmann.com.

Offline illconditioned

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Re: Countryman B3 modification question
« Reply #7 on: November 02, 2022, 08:19:56 PM »
Plenty of folks use them wired directly to a 3.5mm (1/8") stereo plug.  However, Richard stated the following in an older TS thread about them-

You need a source resistor - between black wire and ground, one for each channel.

I use a 2.2k sometimes, for moderately loud stuff.  This works with both plug-in-power and a battery box.  For absolute certainly, use a 4.7k resistor, but in that case, you'll probably want a 9v battery box (or preamp) instead of plug-in-power.

  Richard

[snip..] I'm definitely planning to record some really loud shows in the future. There isn't really any benefit to powering the B3s with 9v without the resistors, is there?
OK, you should have 4.7k in there at all times.  For quiet shows (or ambient stuff) use Plug-in-power.  For loud shows use a regular (2-wire) battery box.

  Richard
Have you got a multimeter?  Measure resistance from both wires to ground (shield).  I think one is already grounded and mods are not needed.
Please DO NOT mail me with tech questions.  I will try to answer in the forums when I get a chance.  Thanks.

Sample recordings at: http://www.soundmann.com.

Offline one8ung

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Re: Countryman B3 modification question
« Reply #8 on: November 02, 2022, 09:40:56 PM »
Have you got a multimeter?  Measure resistance from both wires to ground (shield).  I think one is already grounded and mods are not needed.

Will try it after removing the Lemo connector.

But for now it seems that I am not measuring resistance.
« Last Edit: November 02, 2022, 09:47:42 PM by one8ung »
Mics: Countryman B3 - DPA 4061 - OKM II

Power: A3 Adapter - CA-UBB

Recorders: Tascam DR-2d (3x)

Offline one8ung

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Re: Countryman B3 modification question
« Reply #9 on: November 03, 2022, 04:41:49 AM »
I removed the connector and have a red and white wire and a shield.
I have a connection between the shield and white wire.
Between the red and white wire I measure 11 KΩ
Mics: Countryman B3 - DPA 4061 - OKM II

Power: A3 Adapter - CA-UBB

Recorders: Tascam DR-2d (3x)

Offline commongrounder

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Re: Countryman B3 modification question
« Reply #10 on: November 03, 2022, 11:19:45 AM »
I think two resistors that have the same value should be used. I read somewhere that you should buy multiple resistors and then choose the pair that is the closest to each other. But I could be wrong,  I have no experience with this.

The resistor value should definitely be the same for both mics. Hand matching those resistors with a multimeter isn’t necessary for this application. Most metal film resistors have a tighter tolerance than the reading uncertainty of a DYI-grade multimeter anyway.

Offline kuba e

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Re: Countryman B3 modification question
« Reply #11 on: November 04, 2022, 04:35:33 AM »
commongrounder, thank you for the addition.

 

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