neumann v475 pimping ...

[crisotop]

Is mine an A? it just states V475-2 on the connector and the yellow "type panel". Is the only difference then the missing MO-12 LPF Board? Same pinout as the linked "C" Model?

Thanks a lot!
Christoph

 

[[silent:arts]]

sorry, for the wrong link (corrected).
you should have received one without any Letter, sorry for this confusion too.

mhm, I need an A version - or the schematic - to figure out the difference.
must be the same PCB ... :evil:

 

[philkerg]

Christoph,

For what I understand 475-2 & 475-2A are almost the same, but only the A model has gain control.
Appart from the sticker you can recognize them just by looking the Rg pins;
If something on the card is connected to pins 12&13 (Rg ch1) and 18&19 (Rg ch2) it's a 475-2A with gain control ... lucky guy
If those pins are connected to nothing (just empty holes on the board) ... it's a 475-2 unity gain model .... unlucky.
Unlesss you need an isolating amp

475-2A schem :
http://audio.kubarth.com/rundfunk/getfile.cgi?f=%3D%2C3%28P.3DQ%2C%23DR%2C5%5DV%2BVYE%3D6UA%3BFY%3F%3DC0W-2YG%3A68%60%0A

475-2 schem :
http://audio.kubarth.com/rundfunk/getfile.cgi?f=I%2C3%28P.3DQ%2C3%40V%2CE%5DV%2BVYE%3D6UA%3BFY%3F5C0W-2TR7U-C%3A%265M871I8RYP9%268%60%0A

hope it helps,
phil

 

[philkerg]

Volker you write faster than me :wink:

You can check the shems of the 475-2 vs 475-2A .. follow the 2 links of my previous post.


Phil

 

[crisotop]

Hey Phil,

I got a non "A" version as well - which is fine with me, as I usually work with similar levels, so I just need to figure out the correct summing values for 24 channels, to get decent levels back in the daw (I might stick an eQ + compressor after the summing Box, that will provide some extra makeup gain).

cheers
cri

 

[philkerg]

Sorry my links to kubi's website don't work ....

you will find the schem for the 475-2A in the "any sort of amp" categorie and the file is called :
NEUMANN V475
77.19 kBytes, GIF image data, version 87a, 1988 x 1275
Added: Sun Jan 1 00:39:16 2006

for the 475-2 (without gain control) :same place and the file is called :
NEUMANN V475-2
Schematic
1.27 MBytes, PDF document, version 1.3
Added: Sun Jan 1 01:00:46 2006

 

[[silent:arts]]

ok, can't find an "A" version.

but staring at the PCB and schematics, I'm sure you can convert any V475-2 to the V475-2A (and now I'm sure they used the same PCB)

but anyway, the gain control is overrated :green:
(don't use mine very often)

 

[[silent:arts]]

[quote author="crisotop"]I just need to figure out the correct summing values for 24 channels, to get decent levels back in the daw[/quote]
this is 5K11, doesn't matter if you want 1, 24 or 100 Channels.

 

[Benny]

I'm using my 475-2 without any gain control. No problem if you don't clip it with your DAW-levels. I never needed any gain control. I'm using a GSSL after it and therefore makeup-gain is the only control I need. :grin:

 

[crisotop]

this is 5K11, doesn't matter if you want 1, 24 or 100 Channels.

well that sounds good (doesn't matter if there is signal connected to to the inputs (eg. just using 8 or 16 ins) - if you're not using gain control (would this mean Rg "not connected" compared to a normal 475) how much signal do you get back in terms of dbFS? (I know not every converter line input translates to the same levels, but roughly)

slowly getting there....

No problem if you don't clip it with your DAW-levels.

How much is that in your case? Would be nice to have the DAW faders in a sensitive area (your usual 3/4 up)

thanks!
christoph

 

[[silent:arts]]

christoph,

with 5K11 it is just - unity gain.
putting in +4dBu will result as +4dBu at the ouput.

just make sure your AD converter can't take more than +22 dBu and you are safe :green:

 

[crisotop]

everything clear - thanks a lot volker! +13dBu max i think on my rme, probably a bit less on the motu...

good night,
cri

 

[philkerg]

Hello guys,

I had to leave this discussion yesterday for some diy ... in my kitchen

I'm a bit confused because I realize that I'm mixing what Volker is doing here with some other passive summing designs such as those of NYD.

If i get it right, with a 0 ohm amp such as the 475 there is no gain loss in the network : +4dbu in = +4dbu out (after the amp at unity gain)

There is also no shunt resistor accross the amp input.

Can someone make this a bit clear for me or give me a link to some tutorial about this ...
I looked around , I got some inputs but no definitive explanation.

Many thank's & sorry for these silly questions.
Phil

 

[[silent:arts]]

Phil,

read PRRs posts in this thread:
http://www.groupdiy.com/index.php?topic=5253

:thumb:

 

[philkerg]

Thank's Volker, helpful thread.


Cheers,
Phil

 

[crisotop]

another question volker - how did you mount the V475 in the case? the thing is quite heavy and doesn't have any mounting holes?

thanks!
christoph

 

[philkerg]

Hi,
I was also thinking about this point
little boring details

Maybe yo could redrill the fixing pieces of the connector (I think i did something like that for a 672D) and also use the holes of the little plexigass with the 475 sticker.

And a totally different question .... we discussed about the 15K lowpass filter. Is there such a filter on the 472 amp ? Doesn't look like but I'm not sure .... and if yes how can it be bypassed ?
( I using a 472 as a make up amp for an ela 150 stereo passiv equ. Sounds good actually, but maybe I' missing something )

Thank's
Phil

 

[crisotop]

browse a couple of pages back - volker described what modifications are needed to remove the lowpass filter...

cheers
christoph

 

[[silent:arts]]

Christoph,

for the A version I would use something like this:
Europakartenhalter

the B version I used already has four holes from the shielding metal mounted under the PCB.

 

[crisotop]

this looks like a professional solution - thanks a lot volker!

christoph