Topic: Audio Technica 24 pro and 9v battery box

[peter.star]

Hi Tapers!

I've just purchased a used at 24 mic for my Zoom H2.
Before I've used wm61's and I've made this http://images.suite101static.com/1055511_com_battery_bo.gif for them as a battery box.
Now, I've plugged in the at24 to the b.b. and it doesn't seems to work with it. All I get is very,very low output. The AT mic works fine from it's built in battery and works also fine from the pip of the H2....
What do I miss? Why the AT doesn't like the 9V b.b.?

Cheers!
Peter

[aleal5687]

I thought the atpro24 has a "internal" battery. No need for a battery box.

[peter.star]

Hello!

Yes, it has and it works. I was just surprised, why it doesn't work with the b.b.
And wouldn't be there any benefits from using higher pip voltage than the 1,5 V internal battery or 2,5V's of my H2?

[12milluz]

Hello!

Yes, it has and it works. I was just surprised, why it doesn't work with the b.b.
And wouldn't be there any benefits from using higher pip voltage than the 1,5 V internal battery or 2,5V's of my H2?

Because it uses the 1.5v through a different circuit. That is bias power. The other is phantom power which is (relatively) standard at 48v. Usually the phantom circuit can take 9-48v. It then brings it down to a usable voltage. A battery box will not work with this mic unless it supplies significantly more power than the standard battery box.

[Church-Audio]

Hello!

Yes, it has and it works. I was just surprised, why it doesn't work with the b.b.
And wouldn't be there any benefits from using higher pip voltage than the 1,5 V internal battery or 2,5V's of my H2?

Because it uses the 1.5v through a different circuit. That is bias power. The other is phantom power which is (relatively) standard at 48v. Usually the phantom circuit can take 9-48v. It then brings it down to a usable voltage. A battery box will not work with this mic unless it supplies significantly more power than the standard battery box.

This mic does not operate from Phantom power. The battery box does not work because of the dc blocking caps at the output of the mic are preventing the external battery from powering up the capsules. Remove the caps bypass the 1.2 volt battery and you can externally power these mics with plug in power although I doubt any advantage will be gained from the external battery the mic will most likely overload even after all these modifications more bias power does not necessarily guarantee less distortion.

[12milluz]

Hello!

Yes, it has and it works. I was just surprised, why it doesn't work with the b.b.
And wouldn't be there any benefits from using higher pip voltage than the 1,5 V internal battery or 2,5V's of my H2?

Because it uses the 1.5v through a different circuit. That is bias power. The other is phantom power which is (relatively) standard at 48v. Usually the phantom circuit can take 9-48v. It then brings it down to a usable voltage. A battery box will not work with this mic unless it supplies significantly more power than the standard battery box.

This mic does not operate from Phantom power. The battery box does not work because of the dc blocking caps at the output of the mic are preventing the external battery from powering up the capsules. Remove the caps bypass the 1.2 volt battery and you can externally power these mics with plug in power although I doubt any advantage will be gained from the external battery the mic will most likely overload even after all these modifications more bias power does not necessarily guarantee less distortion.

That's what I get for not actually looking up this mic

[peter.star]

Now I'm totally confused... 
It does work from 2,5 V pip provided by H2, but it doesn't work from 9V provided by b.b.? Huh? If it has caps on the output, how can it work from H2's pip?

[Church-Audio]

Now I'm totally confused... 
It does work from 2,5 V pip provided by H2, but it doesn't work from 9V provided by b.b.? Huh? If it has caps on the output, how can it work from H2's pip?

OK I stand corrected the pro 24 does work from 2 volts to 10 volts plug in power. I personally cant explain why it does not work with your battery box except to say maybe you have an issue with it. Can you provide us with a schematic of the construction of your battery box? Edit : I see the schematic now Looks good to me I thought this mic had an internal 1.2 volt battery. The other thing it could be is there is an issue with your construction of the box. I would check it with a meter on the input * mic input * you should see 9 volts from ground to tip and ring. On the output you should plug in a "load" like your recorder you should see very close to 0 volts or a declining voltage. If you see 9 volts on the output ( its the input ) if you see it on both sides you have a problem with your work. If you see no voltage you have a problem with your work or a dead battery.

[peter.star]

Thanks the advice, I've already checked the mic input of the bb (9V) and output (0V), besides wm61 capsules are working fine with this bb. Quite a mistery for me.

[peter.star]

4,7 k resistor, as in the schematic above.

[Church-Audio]

4,7 k resistor, as in the schematic above.

That value should be fine. You can try 10k but I dont think its going to matter. It sounds like there is an issue with the battery box somewhere.

[peter.star]

Then again, why does it work with the wm61 capsules flawlessly?

[peter.star]

Shorted the bb.: current is 1,98-1,98 mA. Is this okay?