Infos on the Neumann V476b Inductors / Drossel

[Leslie West]

Hi,
thank you all for this very nice Forum.

I have a question about the Inductors in the V476b Preamp from Neumann.
Are they standart HF Inductors, or special ones. One Inductor (DR 5) is build in the Haufe Output xformer, but the HF Filters at the Input (DR 1+2) and all the other (3+4... i don´t know!

How can help me? Who buit these Inductors? Can I replace them with normal HF Filter Inductors?

Thanks in advance

Leslie West

 

[cayocosta]

Is that really you?

 

[Leslie West]

Yes of course...

 

[NewYorkDave]

Leslie from Forest Hills? Hey, welcome to the board!

--Dave from Ridgewood :wink:

 

[Leslie West]

no no no... That was a joke. Sorry....

I am from Germany. Thats only my nickname, because someone said, i played the same way my guitar.... :grin:

 

[cayocosta]

The power of Leslie compels you!

Sit tight, somone should have some answers for you soon.

 

[Leslie West]

[quote author="cayocosta"]The power of Leslie compels you![/quote]

You mean the "avalanche", or?... :grin:

 

[soundguy]

Leslie-

I love "mountain climbing".

why dont you get off your fat ass, stop arguing with the engineers who are trying to help your career and make another good sounding record, we know you have it in you. There are at least two engineers in NY who havent written you off, come look us up.

dave

 

[CJ]

Yeah, and lighten up on the quarter pounders!
:razz:

Rock and Roll McDonalds
Rock and Roll McDonalds

McDonalds sells Big Macs and Quarter Pounders
They will make you fat

Rock Over London
Rock On Chicago
Dupont:Better Living Through PCB's!

:razz:

 

[Leslie West]

Hi,
now we can "climb the mountain" and try to answer my question... :wink:

Are these resistor-like Inductors ok for use in a mic preamp?

http://www.fastron.de/pdf/Msmcc.pdf

 

[NewYorkDave]

The inductance of those chokes is way, way too low to be of any use at audio frequencies.

The formula for inductive reactance is Xl = (2pi)fL, where f is frequency in Hertz, and L is inductance in Henries. As an example, a 1H choke has a reactance of 6.28K at 1kHz.

The highest-valued choke on that datasheet is only 4700 micro-henries (4700 millionths of a Henry).

As it says right on the top of the datasheet, those are RF chokes.

 

[gyraf]

There's two 330uH as RF-filters at the input. These can be standard RF choke types.

Then there's a 100uH in series with the gain-control shunt capacitor and a 270uH as a second RF filter. Also standard RF choke type, I think.

The last one is a 22mH inductor acting as a high-cut filter just before the output stage. This one I think needs to be an audio type or something - not a RF choke.

You may not even want this high-cut filter at all...

Jakob E.

 

[Leslie West]

[quote author="gyraf"]There's two 330uH as RF-filters at the input. These can be standard RF choke types.

Then there's a 100uH in series with the gain-control shunt capacitor and a 270uH as a second RF filter. Also standard RF choke type, I think.[/quote]

Ok, thank you very much.....

[quote author="gyraf"]The last one is a 22mH inductor acting as a high-cut filter just before the output stage. This one I think needs to be an audio type or something - not a RF choke.

You may not even want this high-cut filter at all...

Jakob E.[/quote]

This 22mH one is built in the output transformer from Haufe. I think i will choose a lower capicator to set the Highcut to a higher freq. Will this be ok?

Thanks for your answer...

 

[gyraf]

[quote author="Leslie West"]
This 22mH one is built in the output transformer from Haufe. I think i will choose a lower capicator to set the Highcut to a higher freq. Will this be ok?[/quote]

I think so - but there are three capacitors around that inductor that takes part in the high-cut..

You may need to experiment a bit to get it right..?

Jakob E.

 

[Leslie West]

[quote author="gyraf"]
I think so - but there are three capacitors around that inductor that takes part in the high-cut..

You may need to experiment a bit to get it right..?

Jakob E.[/quote]

Yes. I have to.. :grin: But the 3. capicator of this three going to ground is a "match it" capicator if the tolarance of the 2 before are to big. So I set the second lower as 39 nF and will see what happend...

btw. Sorry for my bad english. I hope you can understand what i mean.....