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Project Specific Discussions => Magnetics => Topic started by: tofufo7 on April 22, 2020, 09:59:51 AM

Title: LEM audio transformer questions
Post by: tofufo7 on April 22, 2020, 09:59:51 AM
Hello everybody,
I would like to know if anybody has ever seen that kind of transfo. I think it should be an input one... but... if any detail...
Thank you
Title: Re: LEM audio transformer questions
Post by: CJ on April 24, 2020, 04:52:13 AM
had to resize, comp is not hooked up to local drive in movie screen,  :D

no, never seen it, did you google it?

looks like you need to have someone take it apart.
Title: Re: LEM audio transformer questions
Post by: abbey road d enfer on April 24, 2020, 07:27:01 AM
Hello everybody,
I would like to know if anybody has ever seen that kind of transfo. I think it should be an input one... but... if any detail...
Thank you
LEM was a French company that distributed microphones from various mfgrs and also transformers made by Melodium. The Melodium company is extinct now since about 25 years. No documents were saved due to the contentious nature of the termination. Most transformers were custom jobs. unless you can identify what piece of gear they come from, you need to evaluate them by yourself. The methods have been discussed here already. PRR and me have proposed two methods.
Title: Re: LEM audio transformer questions
Post by: CJ on April 24, 2020, 04:36:55 PM
could be ribbon xfmr, which some people use for moving coil carts

think i hacked one,
Title: Re: LEM audio transformer questions
Post by: tofufo7 on April 24, 2020, 05:11:32 PM
Hi and thank you so much for your replies.  ;)
In fact, it comes from a card with 8 of them, and I have 2 cards. So, 16 in total.
It was taken from an avintage udio-video system, I think.
LEM was a French company that distributed microphones from various mfgrs and also transformers made by Melodium. The Melodium company is extinct now since about 25 years. No documents were saved due to the contentious nature of the termination. Most transformers were custom jobs. unless you can identify what piece of gear they come from, you need to evaluate them by yourself. The methods have been discussed here already. PRR and me have proposed two methods.
Would be happy to have the link of your two methods, thank you.
Title: Re: LEM audio transformer questions
Post by: CJ on April 24, 2020, 11:59:35 PM
yeah  i did hack a Melodium, different from yours,

ust measure DC resistance and turns ratio if you have a generator and report back

https://groupdiy.com/index.php?topic=67907.msg862950#msg862950
Title: Re: LEM audio transformer questions
Post by: mjrippe on April 25, 2020, 12:15:04 AM
And maybe move this to the Magnetics section?
Title: Re: LEM audio transformer questions
Post by: CJ on April 25, 2020, 12:27:36 AM
yes, the poor and lonely Magnetis section.

i don't know, people check in there but they never checkout ,

like hitch hiking in death valley, you might have to wait for a response and die of dehydration,  :D
Title: Re: LEM audio transformer questions
Post by: tofufo7 on April 27, 2020, 04:25:02 PM
Hi everybody,
thank you for your advices and link.
Will measure DC resistance and turns ratio... will see.
Best!
Title: Re: LEM audio transformer questions
Post by: ruffrecords on April 27, 2020, 05:57:34 PM
If you can it would be worthwhile also measuring inductance at 100Hz (typically) as this will give you some indication of the kind of impedances it expects to work into/outof.

Cheers

Ian