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 on: Yesterday at 09:36:31 pm 
Started by Donn - Last post by soapfoot
Tom Onofrio is a great Neumann tech, as well.

 on: Yesterday at 10:45:04 am 
Started by Donn - Last post by mbrebes
I could probably do it for you.  I am in the Los Angeles area.

 on: April 22, 2019, 07:46:26 pm 
Started by Donn - Last post by Donn
"I just looked at the two different version schematics.  It looks like something a good tech should be able to do."

Yes, that's what Klaus said in the quotation in my original post. I'm hoping for suggestions as to where to send it for the work. Tom Onofrio says he mostly just does Neumann repair to stock, not modifications forward or backwards.


 on: April 22, 2019, 05:35:52 pm 
Started by Donn - Last post by mbrebes
I just looked at the two different version schematics.  It looks like something a good tech should be able to do.

 on: April 22, 2019, 01:24:13 am 
Started by Donn - Last post by Donn

In another post, Klaus made mention of a modification to remove the daughter board of a U87 and do the following modification to versions 03 through 05 (mine is an 04). Can someone recommend to me a U.S based tech (including forum members capable of doing the job). I know Klaus is very busy, and it's apparently not that hard (but not easy enough for me to do myself).


(Klaus' Quote):

So if you want to keep the mic stock, you can keep the coupling cap but you may want to throw out the daughter board of versions #03 though #05 and replace with discrete FET, 47kΩ drain resistor, source cap and resistor (which needs to be biased) and add a 1 gig Ω shut at the FET gate.

All this is fairly easy to do (at least for a mic tech)

 on: April 21, 2019, 09:25:06 pm 
Started by afterlifestudios - Last post by David Satz
They were available until not long ago. But if Bernhard says that the factory doesn't have any more, he would know best about that.

You could try contacting any dealers or distributors who you think might still have one or two in stock. Alternatively, they should be easy enough to make with a 3-D printer, no?

--best regards and good luck

 on: April 21, 2019, 03:08:22 pm 
Started by afterlifestudios - Last post by afterlifestudios
Firstly, I found an old thread here touching on this topic, but could not reply to it (perhaps it is archive only?)  http://repforums.prosoundweb.com/index.php?topic=35503.0

I am in search of a pair of the plastic phase rings for cardioid use of the m934 capsules with m221b microphones.  I have contacted Bernhard Vollmer at Schoeps and he assures me that he cannot provide them.

Do any of you know of a source, or have two that you would be willing to sell?

Thanks in advance,

 on: April 20, 2019, 10:52:08 pm 
Started by Spindrift - Last post by klaus
In the 414EB, the conversion from 9-12VDC to 48VDC phantom powering is achieved by cutting a wire shorting bridge right at the line from the transformer center tap. This activates an 8.2kΩ resistor in series with the 330Ω resistor already present.

The 451also has the 330Ω resistor in the same position, but does not have the 8.2kΩ resistor option for phantom.

I am missing the parts supply sheet for the 452, but its schematic-identical with the 451- also shows one resistor in the same position as the 451's 330Ω resistor. I assume that resistor is an 8.2kΩ value, or thereabouts.

Conclusion: replace the 330Ω resistor in your 451 with an 8.2kΩ - 1/4 watt resistor, and your mic should be well suited for phantom supplies.

 on: April 20, 2019, 04:10:43 pm 
Started by Spindrift - Last post by David Satz
I've been reluctant to reply to this posting because I don't have the specific information at hand. The C 451 was basically a 12-Volt microphone with protection to let it work safely with higher supply voltages as well. But when fed at 48 Volts it drew about 5.5 mA, back when the DIN standard prescribed only 2 mA per microphone.

The page shown below is from AKG's 1979 catalog. A few years after the C 451 was introduced, after problems and complaints arose, AKG introduced a variant model C 452 exclusively for 48-Volt phantom powering. It drew 3 mA--still greater than the value set by the DIN standard--but it brought fewer power supplies to their knees. I remember looking at its circuit and noting that it differed from the C 451 in the value of just one resistor.

Unfortunately I can't find the schematics right now, so I can't tell you which resistor to change to what value. But someone else here probably will know that--and if so, I hope that they'll post here in reply. The changeover can be made quite easily.

--best regards

 on: April 18, 2019, 04:14:17 pm 
Started by klaus - Last post by klaus
... for a pre-1966 Rosewood Strat.
Thought I had one nailed a week ago: a '61, its paint stripped, but with original frets and pickups (both a must, the rest I don't care).

So I am asking here again, exploiting my forum ONCE only, and for a truly charitable cause: playing keeps me sane in an otherwise insanely hazardous field of work. I don't even keep track anymore of how many mic specialists have died prematurely, become alcoholics, drifted into insanity, or permanently froze up under their unmanageable work load.

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