Gus

Gefell conversion confusion
« Reply #40 on: March 03, 2006, 09:57:35 AM »
IIRC first schematic  I removed D1/1   and D1/2,C12

I picked a resistor to install in D1/2,C12 place so I had 12V at the C9 R6 node.  I believe I ended up at 12K I started at 33K.

This would be R8 in the 2nd

I also upgraded a few caps.


DerEber

Gefell conversion confusion
« Reply #41 on: March 03, 2006, 12:17:58 PM »
Quote from: "rodabod"


The only slight problem is that I measured one of my (crap) preamps and it only gives 40V on-loaded.... Hopefully this would only cause less SPL handling and poorer S/N ratio though.



Or it would cause more mods to do  :green:

rodabod

Gefell conversion confusion
« Reply #42 on: March 03, 2006, 12:22:48 PM »
Quote from: "Gus"

I also upgraded a few caps.


Do you think changing the caps is worthwhile?

I heard that the op-amp-like thing that Gefell used (you know, the white SIL chip) is a bit crap and that there is no known replacement because it was a custom part...

I suppose the electrolytics could be quite old on my mics....
Quote from: tv
punchy fat bastard chip

buschfsu

Gefell conversion confusion
« Reply #43 on: July 16, 2007, 02:49:43 PM »
can someone post the complete mv692 schematic?  

also since the 692 supposedly can take 48v is there any advantage to modding it?

i should just be able to replace the 7 pin male with a 3 pin male and connect pin 4 to ground? does that sound right?


thanks
PRR said...
OHM'S LAW. Not as an abstract thing: you should be able to glance at a small circuit and "instantly" know I and V, the way a soccer player glances at the ball and knows the angle and kick

tarandfeathers

Gefell conversion confusion
« Reply #44 on: July 17, 2007, 11:16:41 AM »
I was told that the 'V' in MV692 meant that it would accept 48 V. I tried it once and it made an awful noise so I went back to my 12 V supply. I'd like to convert it for XLR/48 V at some point but other things are taking precedence since it works fine as is. Anyway, my point is, exercise caution when attempting to power these off standard phantom! It might not work!

buschfsu

Gefell conversion confusion
« Reply #45 on: July 17, 2007, 01:56:18 PM »
good advice.  after tracking down the german contact email.  (us site doesn't respond)

i got this reply...................

You can’t power the MV692 with a 7pin connector with 48V.

This MV692 is normally for 12V power.

If you want to operate with 48V you have to converse this microphone.

I can offer you a conversation to 48V with XLR-connector.

The costs are 95€ without German tax.

And it includes the following parts.

 

-new XLR-Connector

-new XLR-Housing

-new preamp-housing

-a regulation IC for 48V-power

-change of some old electronic devices

 
Best regards

 

Michael Militzer

Sales Engineer    

 

 

 

Microtech Gefell GmbH
PRR said...
OHM'S LAW. Not as an abstract thing: you should be able to glance at a small circuit and "instantly" know I and V, the way a soccer player glances at the ball and knows the angle and kick

DerEber

Gefell conversion confusion
« Reply #46 on: July 18, 2007, 06:34:14 AM »
So now you have options. They could mod them for you.
Wich is not DIY, but you will get a new housing, they will change the old noisy FET or OV to a newer one
and you do not have to find a old 7-Pin conector but can use standard XLR cable.
You also could build 12V supply or make some own changes to the mic.
Here are some schematics for you:





 

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