Need help with mic preamp

[Buzzy]

Hi I am building a mic preamp for measurement mic. I am trying to build rod elliot's project 93. The schematic i am building with is figure 6 which is found here Recording and Measurement Microphones

I am using a 9V battery to power it. In the page he says that C5 and C6 should be reversed when using battery power. Is reversing C6 correct ? Its like the positive of C6 is connected to ground. I am confused if it should be this way.

Any help is appreciated. thanks.

 

[Frank Berry]

The instructions are correct. Reverse the polarity of C5 and C6. You must also eliminate R10 and R11.

 

[Buzzy]

Thanks for clarifying. I have built the mic preamp and I am using it. I paired it with a projects unlimited mic. The specs are here AOM-4544L-R

The mic works only when i hold the mic close enough. I actually built the mic to do some measurements of my speaker. I think the mic preamp does not have enough amplification. Is it possible to increase the gain or is this mic just can't be used ?

 

[teleman]

I think you'd be better off using a Panasonic WM61A capsule in Linkwitz mod!
Gives excellent results & is widely used as a measuring mic by many DIYers.The auther,Rod Elliott himself has used this mic in this project.

 

[jorgovanko]

Hi,

if i use this mic preamp ( current URL Recording and Measurement Microphones ) with external power supply which give ~+9V (LM317, discrete PSU or something similar), is this the same as well as to use battery (have to eliminate R10 and R11 and reverse the polarity of C5 and C6)?

Thanks,

 

[tataylino]

Correct! R10 and R11 are only used to get power from mixer's phantom power supply. reverse c5 and c6 also