neumann geffel m73 and the gefell 691 or 692
« on: May 14, 2005, 03:32:09 PM »
hello,
I'm trying to get some mics together so I can finally record.
My ribbons seem to be going as planned and will soon be finished. I'm still working on my cmv7156. (waiting on funds for new tube and parts is more like it)
I have these power supplies for these mics and i have one m73 shotgun capsule made to fit these mics.

I would like to build a mic body to recieve these different capsules from gefell. geffel says the design has not changed in many years.

the 691 MUST have 12v phantom (i know weird) but the 692's will handle 48 volt phantom power.
Both schematics woudl be helpful...the 692 makes a better DIY for obvious reasons....but I have these poser supplies already.

I have 2 power supplies one is wired for XLR the other is the proprietary gefell connections. (and a brand spankin new ps direct from gefell)

I have also DIY'd a regulated ps for these but never implemented it.

I will try to find these schematics but if anyone can offer them that would be great.

I think they would make great DIY mics

ALSO I want to remove the capsule from this m73 so that I can use it for a cardiod mic....it is too big to be practical...of course if anyone has a UM70 head they want to work out a trade for that would be super. :grin: there are a number of quite nice capsules for these mic bodies still available on the market for cheap. This m73 is quite nice i have owned them all at one point and the UM70 rocks completely.

as always your kind comments and suggestions/help are sincerely appreciated.
thanks
ts
I need help with  RCA BA-43/ BA-45. RCA BA-25a, RCA BC3 mic pre's, Gates Level Devil, Federal AM-864u, DIY la2a stuff, Altec 436b


pucho812

neumann geffel m73 and the gefell 691 or 692
« Reply #1 on: May 14, 2005, 04:45:16 PM »
YOu 691 is designed to work with the precursor to phantom power which was known as T power.

Quote
.T-power (short for Tonaderspeisung, also called AB or parallel power, and covered by DIN spec 45595) was developed for portable applications, and is still common in film sound equipment. T-power is usually 12 volts, and the power is connected across the balanced pair through 180 ohm resistors. Only T-power mics may be connected to T-power inputs; dynamic or ribbon mics may be damaged and phantom powered mics will not operate properly
You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is.

neumann geffel m73 and the gefell 691 or 692
« Reply #2 on: May 14, 2005, 05:16:24 PM »
yep that's right pucho....thanks for the additional info on the history/spec for the 691's and T power is definitely short for T..(insert long name here) lol
ts
I need help with  RCA BA-43/ BA-45. RCA BA-25a, RCA BC3 mic pre's, Gates Level Devil, Federal AM-864u, DIY la2a stuff, Altec 436b

neumann geffel m73 and the gefell 691 or 692
« Reply #3 on: May 14, 2005, 06:13:56 PM »




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

neumann geffel m73 and the gefell 691 or 692
« Reply #4 on: May 15, 2005, 12:03:58 AM »
totally sweet pete!!!!
thanks for the schemo's
don't ya'll think this would make good DIY?
Now lets see about sourcing the parts.
I'll look at it and see what I can do.
any help ther would be great too.
thanks
ts
I need help with  RCA BA-43/ BA-45. RCA BA-25a, RCA BC3 mic pre's, Gates Level Devil, Federal AM-864u, DIY la2a stuff, Altec 436b

chriss

neumann geffel m73 and the gefell 691 or 692
« Reply #5 on: May 15, 2005, 06:50:55 AM »
1) I'm not sure if it makes sense to clone these mics since they are so cheap on the s/h-market that parts for a DIY would probably be much more expensive. And it could be difficult to get the specs for the coil.
I'd find it more interesting to know how to mod these mics for lower noise-level.
2) Neumann Gefell never made any of the mentioned mics. Although it's common on ebay to claim that everything manufactured in Gefell is from Neumann these Mics are 'RFT - Mikrofontechnik Gefell'. On the other hand one could say that the Microtech Gefell mics produced today are Neumanns since after the german reunification the company was given back to the Neumann-family. But then Neumanns are Sennheisers really?!...
3) I don't believe that the MV691 uses 'Tonaderspeisung'. You can either use 12V-Phantompower or direct powering with 12V. Phantom or not has nothing to do with the voltages used. F.e. some AKGs have P12-48 stamped on them. So you can use different voltages.

Chris

pigeon

neumann geffel m73 and the gefell 691 or 692
« Reply #6 on: October 25, 2005, 01:12:40 AM »
I just ordered a  Neumann/Gefell MV691 and M70 Capsule a few days ago.  Can i use it with most of my outbaord gear that has 48v phanotm power or do I have to modify it or get a power supply?

Where can i get more info on it and what other capsules can I use with it...really excited about this mic, seem like a versatile tool.
Eddie

chriss

neumann geffel m73 and the gefell 691 or 692
« Reply #7 on: October 25, 2005, 06:25:10 AM »
Eddie,

someone was fooling you. Neumann never ever made a MV691. This was a product from RFT Mikrofontechnik Gefell.
And it should be modified with a voltage-regulator that pulls the 48V down to 12V. You need to remove three parts inside the mic and place the regulator instead. There was another link on the forum with the schamtics for the MV691 and the regulator. Do a search on 'Gefell'.

regards

Chris

jensenmann

neumann geffel m73 and the gefell 691 or 692
« Reply #8 on: October 25, 2005, 09:46:44 AM »
If Eddie ordered it new (yep, still available) then it comes with XLR connector and +48V phantompower. If it´s a used one he has to have a look. There are a lot of modified MV690 around. The mod usually includes an XLR connector.
Jens
Quote from: PRR
The tubes of course don't care what frequency they distort

chriss

neumann geffel m73 and the gefell 691 or 692
« Reply #9 on: October 25, 2005, 03:19:58 PM »
Jens,

are you sure about this? I know the MV692 is still available, but the 691 too??? I don't believe so.


pigeon

neumann geffel m73 and the gefell 691 or 692
« Reply #10 on: October 25, 2005, 03:33:46 PM »
I see, thank you gentelmen.

Eddie

jensenmann

neumann geffel m73 and the gefell 691 or 692
« Reply #11 on: October 25, 2005, 05:09:47 PM »
ok, chriss is again right, the MV692 is available, not the MV691 :oops:
I should think first and talk later :green:
Jens
Quote from: PRR
The tubes of course don't care what frequency they distort

chriss

neumann geffel m73 and the gefell 691 or 692
« Reply #12 on: October 26, 2005, 04:59:08 AM »
Quote
ok, chriss is again right,


Did I win a price? :cool:

By the way if anyone is interested in modding the MV692 to XLR/P48 I stronly recommend to send it to Gefell. A friend of mine just did so and they changed the housing-tube to a new one that looks awesome. Silver with engraved MG-Logo, not white silk-screen on black laquer as the earlier ones. I don't remember the exact price but it was not very much. 70 Euros or so?

Chris


 

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