Neumann V475 adapted in its own box to go after standard passive summing?

Basically as the headline asks, is this possible?

I read in the V475 summing threads that it likes 5.1K resistors for the resistor network (based on 24 ins I think) and doesn't need a resistor across on the end as far as I remember it.

Is there a way to adapt it so it can go on the back of any passive summing for amplification, say like  Folcrom?

Any wise thoughts very appreciated.

Why would you like to do this?

5K1 resistors are channel independent. Up to 100+ Channels.
You could do a box with the 5K1 summing network, and do the shunt resistor switchable.

karloff70 said:

Basically as the headline asks, is this possible?

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I don't see why it wouldn't work, somehow. But it may not be optimized.

I read in the V475 summing threads that it likes 5.1K resistors for the resistor network  (based on 24 ins I think)

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It is just that it's unity gain when the injection resistors sum at about 10k. If they sum at about 20k, the gain would be -6dB.

and doesn't need a resistor across on the end as far as I remember it.

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Since it's a VE input, a shunt resistor would not change the gain; it would just increase noise.

Is there a way to adapt it so it can go on the back of any passive summing for amplification, say like  Folcrom?

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The only adaptation would be to remove the shunt resistor; since the Folcrom is spec'd at 10k balanced, it should be adequate for the V475.

> it's a VE input

So then this is not "passive" summing, eh?

I don't have a religious opinion one way or the other. But people who say "passive summing" would be offended if summed actively.

PRR said:

> it's a VE input

So then this is not "passive" summing, eh?

I don't have a religious opinion one way or the other. But people who say "passive summing" would be offended if summed actively.

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You're the one calling things by their proper names  ;D
I managed not to tread this potentially controversial minefield 

I also like to call the things by their proper names, sometimes I know I don't know the right english term so I put '...or whatever you call it' or something, I think it's good practice to do so so we understand each other better. In this case we understand anyway but still, could cause confusions when it starts to get more detailed.

JS

So if one was to put a V475 on the end of a passive resistor network it would be a good idea to remove the shunt resistor. And the resistor network values merely affect gain, 5.1K making it unity throughout. Correct?

And yes, once the Neumann is involved it is no longer passive......worms, back in the can, please.....

karloff70 said:

So if one was to put a V475 on the end of a passive resistor network it would be a good idea to remove the shunt resistor.

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Definitely. The shunt resistor , to a limit, doesn't change the signal gain, but it makes the opamp work harder, resulting in more distortion, more noise and impaired frequency response.

And the resistor network values merely affect gain, 5.1K making it unity throughout. Correct?

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That's 2x5.1k for balanced bus or 1x10k for unbalanced.

So if I have an already built passive summing box wired balanced with 10K's in it, if I remove the shunts I can strap the V475 after it, only the level won't be unison?

karloff70 said:

So if I have an already built passive summing box wired balanced with 10K's in it, if I remove the shunts I can strap the V475 after it, only the level won't be unison?

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Level would be -6dB, but there is some adjustment possible via the internal trimmers.

Done deal, I'll have to try that out then.....

Thanks everyone!