Topic: I have built my own battery box and it doesn't work fine....

[tris1979]

Hello, I need your help...
I have bought a pair of AT831 to replace my poor quality sony microphone. I have built a battery box to use them with my pcm-m1. I did some recordings last week-end, and it didn't work fine. I have recorded two concerts, one with a guitar and a voice in a small place and it sounds fine but the other recording it was a rock band: Bass, guitar, drum and vocals, and the result was of bad quality sound, with distortion. I know that it doesn't come from the DAT recorder but from the Battery Box, maybe the voltage is not enough to supply microphone (5V) or the capacitor is to small to cut off  sub bass. The microphone should be able to withstand level is 140 db at 1khz as noticed there http://www.audio-technica.com/prodpro/profiles/AT831R.html
so I does not understand why it doesn't work.
Here is the shematic of what I have built : 
 http://tris19792.free.fr/AT831%20Battery%20BOX.pdf

Here is a shematic of the way to supply the microphone from Audio technica website:
 http://tris19792.free.fr/AT831%20WiringInfo.pdf


I will try to change the value of the resistors and from the capacitor, but if any of you has some ideas, your welcome.
tristan1979@wanadoo.fr

Regards.
Tristan.

Sorry for my english, I'm french....

[dklein]

That first page says you need Phantom power:
Phantom Power Requirements
9 - 52V, 2 mA typical

What kind of box did you build - what voltage, resistors and caps? 

[tris1979]

The AT831R version with phantom power (with TA3F power module) need a Phantom power beetween 9-52V (from the sounboard), but the microphone only need supply beetween 1.1 to 12V to work (http://tris19792.free.fr/AT831%20WiringInfo.pdf)


 my battery box provide a 5V with the DAT connected. Resistor are 10k? and caps 3.3µ....

[super-phat-al]

this may sound stupid but did you plug it in to the line in or mic in on the DAT?  it looks like you know your stuff, but i thought it wouldn'r hurt to ask

[tris1979]

I was plugged into the mic input with a -20dB Pad and the sensitivity was at something like 4 (rec volume from my M1). The Vu-Meter was at something like -6dB (and was not able to move from this position).... Maybe I have to do some test with a -20dB pad before the input or in the line input, but that is strange if the distortion is coming from the mic input of the dat...

Does my battery box schematic looks good for you??
thank you.

[tris1979]

Hello, It seem's that I'm stupid, I did some test at home with the line input, and...... It seem's to work fine....SIC

So If I'm not wrong the sensitivity in the mic input with the pad (-20db) is less important that in the line input, the delivery level from the AT831 is too hot for the mic level....

Did someone experienced that? Does someone has the electrical specifications for the inputs of the PCM-M1, How can I check the output level from my mic?

thank you

[tris1979]

thank you,
If I change the value of the resistors from 10kohm to maybe 5, i should have a highter supply voltage for the mic...
Do you think that 5v is not enough to supply the mics?

[zhianosatch]

I don't speak electrical lingo very well, and I'm always amazed at people such as yourself that do these things,....
That being said, take my comments witha grain of salt,....

The operating range, as stated above, says 9>52 volts for operation.

Pure speculation on my part, as an untrained layperson,....
The higher your voltages the less distrotion you'll get, cuz the mic isn't straining to operate properly.

surely someone can put this into more professional terms.

get jon in here

[Sean Gallemore]

5V is the norm
that's even what the DPAs run off of

the 9-52 is a phantom power only thing, and even then one cannot run it straight to the mics.  Adapters must be used, such as the AT8533/AT8533x/AT8531/SamsonPM4 in this case or the DAD600X in the case of the DPAs

[tris1979]

thanks, so I will let the supply at 5V, and do other test in real condition... I'm not planning to use them with a sounboard phantom power, so I don't need  AT8533/AT8533x/AT8531/SamsonPM4 ...

It seems that mic in input with the -20db "pad" is the noninal level for the mic input, when you use the mic in 0dB position you have a gain of 20dB. So If you want a real -20dB PAD you have to use the line in input.... http://www.sonicstudios.com/d100page4.html

I will do more test next week so I will see if it's OK...
Thank you

[leegeddy]

>>It seems that mic in input with the -20db "pad" is the noninal level for the mic input, when you use the mic in 0dB position you have a gain of 20dB. So If you want a real -20dB PAD you have to use the line in input....

the 20dB pad on the M1 is not in effect with the line-in, only in mic-in.

marc
 

[Sean Gallemore]

+

backatcha big M

[zhianosatch]

der backatchen