Topic: Help to identify these transformers?

[Chuck]

Do these audio transformers look familiar to anyone?
Possibly Radio Shack or other low to high impedence matching transformers? I happen to have a project that could use just that type of thing. I'm just wondering if anyone knows by looking what they actually are.

Thanks,
Chuck

[it-goes-to-eleven]

Those are the transformers Doug uses in the 148!

[Chuck]

Those are the transformers Doug uses in the 148!

I wish...

[Church-Audio]

Do these audio transformers look familiar to anyone?
Possibly Radio Shack or other low to high impedence matching transformers? I happen to have a project that could use just that type of thing. I'm just wondering if anyone knows by looking what they actually are.

Thanks,
Chuck

There is no way to tell by looking but to me they look like Shure sm 58/57  transformers. Hi to Low imp. The reason why I say that is they have the correct Yellow plastic tape and they use the same wire color scheme as Shure does for the transformers they use

[Chuck]

Thanks for the input Chris. I have been in the "guts" of several SM57's and made the same observation regarding the yellow tape on the transformers in those microphones. I posted the photo because I think these are relatively common transformers that may be recognizable just by sight. Perhaps the transformers that are in the Radio Shack, Hosa, Audio Technica or other popular balanced XLR (low Z) to phono plug (high z) converters?

[Church-Audio]

Thanks for the input Chris. I have been in the "guts" of several SM57's and made the same observation regarding the yellow tape on the transformers in those microphones. I posted the photo because I think these are relatively common transformers that may be recognizable just by sight. Perhaps the transformers that are in the Radio Shack, Hosa, Audio Technica or other popular balanced XLR (low Z) to phono plug (high z) converters?

I think its safe to say that's what you have here is some high to low impedance transformers. The only way to measure them is with an impedance meter (not a cheap toy) If I am correct, the Red Blue side is low the Yellow Green side is Hi imp. The primary colors would be + So red should be + and Yellow should be + Green will be - and Blue will be -

I would try sending some signal though them. But the real question is 1- what is the insertion loss in DB and 2- what is the Frequency response we know these are not high end transformers audio transformers, simply because they are not Faraday shielded. They would be in a metal can of some type. Just to let you know I have seen jensen transformers on eBay sell for as little as $20 a pair, the specs are known for these types and  if your doing anything of importance I would simply look on eBay. Most cheap transformers like these are lucky to do 40hz to 15k Most mic companies Use cheap transformers like this to act as a high pass filter to reduce distortion and obviously impedance matching.

[Chuck]

Thanks for the input Chris. I have been in the "guts" of several SM57's and made the same observation regarding the yellow tape on the transformers in those microphones. I posted the photo because I think these are relatively common transformers that may be recognizable just by sight. Perhaps the transformers that are in the Radio Shack, Hosa, Audio Technica or other popular balanced XLR (low Z) to phono plug (high z) converters?

I think its safe to say that's what you have here is some high to low impedance transformers. The only way to measure them is with an impedance meter (not a cheap toy) If I am correct, the Red Blue side is low the Yellow Green side is Hi imp. The primary colors would be + So red should be + and Yellow should be + Green will be - and Blue will be -

I would try sending some signal though them. But the real question is 1- what is the insertion loss in DB and 2- what is the Frequency response we know these are not high end transformers audio transformers, simply because they are not Faraday shielded. They would be in a metal can of some type. Just to let you know I have seen jensen transformers on eBay sell for as little as $20 a pair, the specs are known for these types and  if your doing anything of importance I would simply look on eBay. Most cheap transformers like these are lucky to do 40hz to 15k Most mic companies Use cheap transformers like this to act as a high pass filter to reduce distortion and obviously impedance matching.

+T, and thank you very much for sharing that information.
I didn't know there are specific rules regarding the color coding of the leads and how it applies to transformers. I do know about Jensen transformers, but was not aware that they can be bought so cheaply. I have seen the quality Jensen transformers in the sheilded cans and figured these were certainly cheap, but perhaps usable for something. I guess I'll have to get out some alligator clips and run some signal through them to see what they do.

[Church-Audio]

Thanks for the input Chris. I have been in the "guts" of several SM57's and made the same observation regarding the yellow tape on the transformers in those microphones. I posted the photo because I think these are relatively common transformers that may be recognizable just by sight. Perhaps the transformers that are in the Radio Shack, Hosa, Audio Technica or other popular balanced XLR (low Z) to phono plug (high z) converters?

I think its safe to say that's what you have here is some high to low impedance transformers. The only way to measure them is with an impedance meter (not a cheap toy) If I am correct, the Red Blue side is low the Yellow Green side is Hi imp. The primary colors would be + So red should be + and Yellow should be + Green will be - and Blue will be -

I would try sending some signal though them. But the real question is 1- what is the insertion loss in DB and 2- what is the Frequency response we know these are not high end transformers audio transformers, simply because they are not Faraday shielded. They would be in a metal can of some type. Just to let you know I have seen jensen transformers on eBay sell for as little as $20 a pair, the specs are known for these types and  if your doing anything of importance I would simply look on eBay. Most cheap transformers like these are lucky to do 40hz to 15k Most mic companies Use cheap transformers like this to act as a high pass filter to reduce distortion and obviously impedance matching.

+T, and thank you very much for sharing that information.
I didn't know there are specific rules regarding the color coding of the leads and how it applies to transformers. I do know about Jensen transformers, but was not aware that they can be bought so cheaply. I have seen the quality Jensen transformers in the sheilded cans and figured these were certainly cheap, but perhaps usable for something. I guess I'll have to get out some alligator clips and run some signal through them to see what they do.

You can try to download a sample program called winaudiomls and see what they do MLS measurements via a loopback thru your computers sound card will give you a frequencey graph of the reponse curve. I would use 65000 sample setting for best resolution here is a link to that free software. I have the lab version, but this will work just fine. http://www.dr-jordan-design.de/Downloads.htm
Also check these auctions out
 
http://cgi.ebay.ca/Jensen-150-600-audio-transformer-PAIR-JE-11SSP-8M_W0QQitemZ110036653694QQihZ001QQcategoryZ67815QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ebayphotohosting

http://cgi.ebay.com/TAMURA-TF-3WL-AUDIO-TUBE-AMP-INPUT-TRANSFORMERS_W0QQitemZ120036429989QQihZ002QQcategoryZ67815QQrdZ1QQcmdZViewItem#ebayphotohosting

http://cgi.ebay.com/TAMRADIO-TAMURA-L1-D-AUDIO-INPUT-TRANSFORMERS_W0QQitemZ120036429647QQihZ002QQcategoryZ67815QQrdZ1QQcmdZViewItem