C12 VR boost switches position

[ghiatorino]

I searched some info and found that the VR has an internal  boost control via 3 small switches. Mine are in this position (picture attached), anybody knows if the boost is engaged or not? Since i bought it used i would like to know the standard position of the 3 switches and the +10dB position of the individual switches. Many thanks, T.

 

[ln76d]

http://cloud.akg.com/7740/c12vr_manual.pdf

 

[RuudNL]

How to change the sensitivity of the microphone?
The circuit design incorporates the facility to increase the nominal
sensitivity of the microphone by 10 dB. This basic change
to the microphone’s data may be made by the user in the following
manner:
1. Open the microphone according to the description in the last
paragraph.
2. On the top left corner of the transformer board are three
small p. c. board switches placed next to each other. Change
all three switches to the opposite position with a small
object, like ball-pen or similar.
3. Close the microphone in reverse order of the opening procedure.

 

[ghiatorino]

I have read that info, but don't know if the position i found is the way the mic is in stock version, since it's a second hand purchase

 

[ln76d]

I really don't know, where's your problem

You have only two positions -> 0dB and +10dB. Definately +10dB isn't factory setup.
If you don't know which position is 0 and which +10, just change it and listen, you will hear the difference, if not i would sold that microphone
You can always trace circuit it isn't complicated.
http://www.filmsoundsweden.se/backspegel/akg-c12vr.html

 

[ghiatorino]

No problems of course, the question is just if anybody knows in which position the switches are as AKG sells it. You have 2 operating ways  (0 / +10) but 3 switches make 6 possibilities, i don't want to play around randomly, and it's not trivial to understand it from the schematic. My question is just because the mic isn't sounding as i was expecting. furthermore i saw pictures of the switches all the way up or down, not like they are in my mic, so here's the suspect something isn't properly right. Anyway thanks for jumping in

 

[ln76d]

I have read that info, but don't know if the position i found is the way the mic is in stock version, since it's a second hand purchase

Read again:

"Change all three switches to the opposite position with a small
object, like ball-pen or similar."

You have 2 operating ways  (0 / +10) but 3 switches make 6 possibilities,

and again:

"Change all three switches"

Now you get it?

There's no 6 possibilities - still only two, but you need to operate with all three switches simultaneously.

 

[ln76d]

If there still would be something unclear, here's something for you
You need to click on the picture

 

[ghiatorino]

One switch is up, other 2's are down, and i found that is not a correct configuration (so switching all together will be another mistake).
Anyway i found the answer in the service manual drawings. 3 switches all the way down is 1mV/Pa . Up is +10dB .
Thanks for helping
t

 

[ln76d]

and it's not trivial to understand it from the schematic.

Here's how it works if you would like to know what change in the circuit it makes.

One switch is up, other 2's are down, and i found that is not a correct configuration (so switching all together will be another mistake).
Anyway i found the answer in the service manual drawings. 3 switches all the way down is 1mV/Pa . Up is +10dB .
Thanks for helping
t

You need to switch it all together but always all need to be in the same position as on the gif.

 

[davidmen]

First switch enables the second stage of the 6072, giving you a 10db boost.
Second switch disconnects the output tx of the first stage 6072.
Third switch flips the polarity (and connects the tx to second stage) of the tx since if you engaged the second stage
will be out of phase, so this switch corrects this.

 

[RuudNL]

I think by now (6 years later) he will have found how to do it!

 

[davidmen]

I think by now (6 years later) he will have found how to do it!

Ha! I didn't notice the date!