Transformer options for the g7 circuit

hejsan

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Hello.
I've tried a search for this, but the results were to confusing.

I'm going to build three different g7 mics, and I am wondering what transfomers I could use. I'm going to use the "classic" lundahl for one, but I would like to get different types to have different flavours without having to do circuit mods (not my strong side), unless someone has a complete mod available.

Does anyone know which cinemag will work (and sound good) in a g7?
Is there some sowter that could work?
What's the price difference?
Something else?

I've just bought 3 different capsules from peluso (the three double sided ones) And suddenly started wondering if they will all work for this circuit?

Any info appreciated, thanks,
Hejsan
 

sbranco

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Hey good luck with your project. i have thought about the same thing.

I am not an expert but I think you just need to go to the Lundhal site and see what ratio the recommended Lundhal transformer is (I forget now) and get another transformer from Cinemag or Sowter that is close to that ratio. I am sure that both companies make a suitable replacement for it and it should work fine.
 

mcs

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I think some people have used the OEPs also.

Best regards,

Mikkel C. Simonsen
 

hejsan

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Ok thanks.
But aren't there some other parameters than the ratio that need to be the same, like current and voltage handling and whotnot?

Anyone with experience in the field care to make a more specific suggestion, like part numbers that would definetly work and maybe what to expect sound vise?

It would be great to hear of cinemag and sowter types since I kind of get the feeling that they are more reputable in the pro audio scene than OEP and others. I figure there must be some reason for their vibe :?:
 

sbranco

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I am only parroting what I have heard on this board and I may be talking out of my derrier so take what I say with a grain of salt. We are trying to convert a mic into a G7 using a cinemag transformer.

The lundhals are supposed to have just a little color but very clean.

The cinemags have color as do the sowters.

All are thought of as very good transformers. You could also use a Jensen but supposedly they are more expensive and no better than the Cinemags.

Cinemag has a website. I think its cinemag.biz but you can google cinemag and you'll find it. They are helpful at choosing transformers for a specific app but they also actually list mic output transformers on their web page. The web also lists sizes and specs for the transformers.

I think Lundhal also lists their mic output transformers with specs on their website. It was greek to me but maybe you could use the Lundhal specs and then compare them to the products offered by Cinemag and Sowter.

My understanding is that the G7 circuit is pretty forgiving and even different ratio transformers might work just fine for you. We are going to try a 10:1 ratio transformer when I think the recommended Lundhal is a 5:1. And I am pretty sure there will not be a problem! (with that at least)

I think the operative thing is that you buy a quality transformer that is at least in the realm of what you need. The original Royer mic mod for example used a Jensen transformer that is recommended for direct boxes, not microphones! The current you are talking about is super small so I don't think that is an issue. A higher ratio will actually give you less signal opposite of what you would think. But the lower ratio transformers are also bigger and size gets to be an issue.

The Cinemag guys sell lots of mic transformers to manufacturers and may be better able to answer your questions. You'll probably want at least one transformer from them anyway.
 

hejsan

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Oct 3, 2005
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Iceland
Thanks for the info :grin:
I have been thinking about the CM-2461NiCo which they ab tested against a neuman transformer. That one is 6.5 : 1 which is pretty close.
I'm going to ask them for a quote, and also ask them about other possible substitutes. This didn't actually strike me as a very coloured, it seemed very crisp compared to the neuman, but I don't really have enough experience to tell.
 
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