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Gear / Technical Help => Microphones & Setup => Topic started by: Roving Sign on December 18, 2008, 09:20:18 AM

Title: Question about Nak 300 transformers...
Post by: Roving Sign on December 18, 2008, 09:20:18 AM
When using a balanced XLR connection, is the transformer still in the signal path...???

thanks!
Title: Re: Question about Nak 300 transformers...
Post by: SmokinJoe on December 19, 2008, 11:27:35 AM
Yes.

The transformer is in the body... if you are using a traditional Nak300 you are using the impedance transformer.  If you have a "mod'ed active" one, you don't have a transformer.

The Nak literature has some comments about balanced and unbalanced cables... but almost everyone now is using standard balanced XLR cables into a modern preamp.
Title: Re: Question about Nak 300 transformers...
Post by: Roving Sign on December 19, 2008, 12:33:57 PM
Yes.

The transformer is in the body... if you are using a traditional Nak300 you are using the impedance transformer.  If you have a "mod'ed active" one, you don't have a transformer.

The Nak literature has some comments about balanced and unbalanced cables... but almost everyone now is using standard balanced XLR cables into a modern preamp.

Can one run these transformerless without going as far as "active" mods?

I was wondering if the lo-cut switch could be turned into something more useful - like switching in or out the transformer...
Title: Re: Question about Nak 300 transformers...
Post by: Church-Audio on December 19, 2008, 12:37:17 PM
Yes.

The transformer is in the body... if you are using a traditional Nak300 you are using the impedance transformer.  If you have a "mod'ed active" one, you don't have a transformer.

The Nak literature has some comments about balanced and unbalanced cables... but almost everyone now is using standard balanced XLR cables into a modern preamp.

Can one run these transformerless without going as far as "active" mods?

I was wondering if the lo-cut switch could be turned into something more useful - like switching in or out the transformer...

Not with out reworking the circuit you still need an impedance converter. You could make them active and then run them into a phantom power adaptor. That would work

Chris
Title: Re: Question about Nak 300 transformers...
Post by: Roving Sign on December 19, 2008, 12:46:13 PM
Thanks - I was just wondering out loud - trying to think of ways of cleaning up the stock mic or changing the mic beyond the active mod thing...

Like - the ones I've opened, seems like they used about 10 X more solder on those little boards than you might think was necessary...could one clean up that kind of thing? Would it matter?
Title: Re: Question about Nak 300 transformers...
Post by: Church-Audio on December 19, 2008, 12:52:20 PM
Thanks - I was just wondering out loud - trying to think of ways of cleaning up the stock mic or changing the mic beyond the active mod thing...

Like - the ones I've opened, seems like they used about 10 X more solder on those little boards than you might think was necessary...could one clean up that kind of thing? Would it matter?

Its really not going to make any difference. They are very tricky these mics when your putting them back together you have to watch the ground tab on the capsule makes good contact with the mic housing. If not you end up with noise and poor performance.
Title: Re: Question about Nak 300 transformers...
Post by: Roving Sign on December 19, 2008, 12:55:10 PM
Thanks - I was just wondering out loud - trying to think of ways of cleaning up the stock mic or changing the mic beyond the active mod thing...

Like - the ones I've opened, seems like they used about 10 X more solder on those little boards than you might think was necessary...could one clean up that kind of thing? Would it matter?

Its really not going to make any difference. They are very tricky these mics when your putting them back together you have to watch the ground tab on the capsule makes good contact with the mic housing. If not you end up with noise and poor performance.

Same with the threads - they can get gooky after awhile, use your fingernail and some solvent to keep them clean...
Title: Re: Question about Nak 300 transformers...
Post by: giveaway on December 19, 2008, 01:01:59 PM
Sorry to be off-topic, but do any of you have a good book recommendation on microphone technology?  Like, "The Complete Idiots Guide to How Microphones Work" or something?  This thread is interesting and I'd like to be able to follow these discussions in the phuture.
Title: Re: Question about Nak 300 transformers...
Post by: Roger Gustavsson on December 23, 2008, 02:19:32 AM
You can take a look at http://en.wikipedia.org/wiki/Microphone

Roger
Title: Re: Question about Nak 300 transformers...
Post by: audBall on December 23, 2008, 09:39:54 AM
Not with out reworking the circuit you still need an impedance converter. You could make them active and then run them into a phantom power adaptor. That would work

The concept of running naks TL has crossed mind quite a bit.  I do know that certain phantom adapters (dunno if all) incorporate output transformers.  The Samson PM4 does, which I use.  I also noticed that a member on this board has a JK Labs modded PM4.  I'm assuming a different tranny was installed  ???

I think the only way to run them TL is into a bbox or pre like Church's.  Or, if the phantom adapter is TL.  Does anyone know for sure of any that are?

Nice thread... 
Title: Re: Question about Nak 300 transformers...
Post by: Roger Gustavsson on December 24, 2008, 04:54:09 AM
They can be run without the transformer into almost any non-balanced input. Without the transformer the output impedance will rise to about 500 Ohm and the cables should be keept shorter. I have used mine with 12 meter long cables without problems. The output level will rise by at least 10dB without the transformer. Less gain will be needed for a given level.

It is also possible to modify the electronics to a Scheops-like balanced output, with internal battery (12V) or external phantom supply (12, 24 or 48V). Output will be about 12mV (some 18dB above the original ones). The microphone bodies can be cut down in length too. Both examples below, will fit inside the original impedance converter housing.

http://www.twin-x.com/groupdiy/albums/userpics/nakamichi_schoeps.JPG
http://www.twin-x.com/groupdiy/albums/userpics/schoepsmini.pdf

Another way is to use a Chargeamp. In many cases no need for any mic preamp at all.  

http://www.twin-x.com/groupdiy/albums/userpics/mike1.GIF

Here is one following the schematic at the second ciruit, some values changed.

http://www.twin-x.com/groupdiy/albums/userpics/upfrontamp.pdf


Maybe someone can help me with circuit boards?



Roger