ytrehalf

Gefell MV690 12v-48v modification
« on: August 10, 2004, 10:55:08 PM »
Hello,
     I bought a Gefell MV690 a while ago intending to build a power supply for it. But now I'm considering converting the microphone to use phantom power, instead. I'd like to switch the 7 pin connector to an XLR as well.

Does anyone have any information on this modification?


tony dB

Gefell MV690 12v-48v modification
« Reply #1 on: August 11, 2004, 07:39:07 AM »
have you tried gefell?

Gefell MV690 12v-48v modification
« Reply #2 on: August 11, 2004, 09:10:16 AM »
http://www.lazpro.com
I reserve the right to not sell to idiots

[silent:arts]

Gefell MV690 12v-48v modification
« Reply #3 on: August 11, 2004, 09:27:24 AM »

PRR

Gefell MV690 12v-48v modification
« Reply #4 on: August 11, 2004, 11:33:30 AM »
Edit: this will NOT work (without internal cutting):


Gus

Gefell MV690 12v-48v modification
« Reply #5 on: August 11, 2004, 11:57:04 AM »
I have 2 692s with the Gefell factory 48V phantom change.   I will try to draw the mod tonight.  I forgot about this I told Peter I would do this some time ago.

zebra50

Gefell MV690 12v-48v modification
« Reply #6 on: August 12, 2004, 02:07:29 PM »
here's Gus's sketch



Cheers! :thumb: z50
Ribbon microphone services
http://www.xaudia.com
Microphone blog

ytrehalf

Gefell MV690 12v-48v modification
« Reply #7 on: August 13, 2004, 01:59:03 AM »
Thanks Fellas!

 :guinness:  :guinness:  :guinness:  :guinness:  :guinness:  :guinness:

volki

Gefell MV690 12v-48v modification
« Reply #8 on: August 13, 2004, 02:13:30 AM »
cool silentarts, now i finally have the 690 schem, too... :thumb:

the gefell people are very nice - when i sent them one of my 691's with UM70 for cleaning of the capsule, they said "oh, this 3rd party p48 mod wasn't done quite right, we'd like to redo it. we're also gonna throw out that russian FET, which is too noisy anyway, and stuff. oh, and while we're at, the old chassis looks so worn, we'll provide a new one so it looks decent when it leaves our house."

they did all this at a remarkably low price... great. :green:

mig27

Gefell MV690 12v-48v modification
« Reply #9 on: August 13, 2004, 10:06:26 AM »
I've also had very good experiences with the folks at Gefell.
They once completely cleaned and refurbed a capsule without charging anything for it.

way to go.


Gefell MV690 12v-48v modification
« Reply #10 on: August 13, 2004, 04:00:21 PM »
Gus,
Are you saying that you have a little additional pcb in there similar to this?

Can anyone kindly translate...pretty pretty please.

http://www.lazpro.com
I reserve the right to not sell to idiots

Gus

Gefell MV690 12v-48v modification
« Reply #11 on: August 13, 2004, 04:06:54 PM »
Peter

    I don't have a board in my microphones.  It looks like a factory mod.   I say this because the connector was machined again for the XLR.   The machine work is nice.  I will take a picture of the inside.

Gefell MV690 12v-48v modification
« Reply #12 on: August 13, 2004, 04:13:07 PM »
Marvellous stuff Gus.
http://www.lazpro.com
I reserve the right to not sell to idiots

ytrehalf

Gefell MV690 12v-48v modification
« Reply #13 on: August 13, 2004, 10:34:33 PM »
Gus, in your drawing I see the 12v zener, but what is the value of the other diode?

0.6v?

volki

Gefell MV690 12v-48v modification
« Reply #14 on: August 14, 2004, 02:44:48 AM »
Quote from: "peter purpose"
Can anyone kindly translate...pretty pretty please.
]


"umbau" = modification
"BE-Seite" = main PCB component side

(below) remove C12 (10nF) and D3/2 (SAY60)
(right) insert 48V PCB. note: use extra isolation for both leg C and the whole PCB
(bottom) main PCB solder side

that's all you gotta know.

Gefell MV690 12v-48v modification
« Reply #15 on: August 14, 2004, 08:18:25 AM »
Great stuff...thanks volki.. :thumb:
http://www.lazpro.com
I reserve the right to not sell to idiots

Gefell MV690 12v-48v modification
« Reply #16 on: August 14, 2004, 09:45:26 PM »
Guys.....are we going to an awful lot of trouble here?

12V version


48V version


Won't the variable resistor just take the voltage down to the desired value?

peter
http://www.lazpro.com
I reserve the right to not sell to idiots

Gefell MV690 12v-48v modification
« Reply #17 on: August 17, 2004, 08:34:00 PM »
Quote from: "ytrehalf"
Gus, in your drawing I see the 12v zener, but what is the value of the other diode?

0.6v?


Brendan,
My simulated circuit uses a 1N4007 and all looks pretty good.

peter

http://www.lazpro.com
I reserve the right to not sell to idiots

ytrehalf

Gefell MV690 12v-48v modification
« Reply #18 on: August 18, 2004, 03:40:00 AM »
Thanks Peter!

 :grin:  :grin:  :grin:

Gefell MV690 12v-48v modification
« Reply #19 on: August 18, 2004, 11:31:10 AM »
One other thing.......
I made a connector by taking a neutrik face mount and cutting off the flange. Remove the spring jobbie in the gefell original and ream it out about half a mm, then apply a little glue and slip in the neutrik.

http://www.lazpro.com
I reserve the right to not sell to idiots


 

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