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Stephan Gipp Stephan Gipp is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphonesto modern MP3 player

Good Music wrote:

For Mouser's audio transformer products, they have spec sheets where they
have the "impedance (ohms)" rated on both the primary and the secondary
windings.

If my headphones are 8 ohms and my MP3 player is expecting headphones in the
40-100 ohm range, is it as simple as buying an audio transformer with
reasonably wide-range frequency response, and 8 ohms on one winding, and
40-100 ohms on the other winding?


Pretty much. In the general case you need to worry about watts also, but
in the case of headsphones .. not really. Also, getting something 'kind
of close' might be just enough. At the moment, your 8 Ohm headphone is,
say, a factor of 5-10 away from what the iPod is happy to deal with. So
of you get something 'closer' ... might just be good enough. So if you
look for a transformer that has 8 on one side and 50-200 on the other,
should work. Also, keep in mind that there is no difference between
primary and secondary in terms of what goes where.


And once I buy two transformers (one per channel), is it as simple as (for
each channel) connecting the 8-ohm headphone driver to the "common" and
"hot" leads for whichever winding is rated 8 ohms, and the 1/8" headphone
jack's "common" and "hot" leads to the other winding? Or, is there maybe
some reason I'm supposed to connect it in the OPPOSITE way?


Per channel, just put the 8 Ohm connection on the side of the headphones
and connect the other side with the iPod.


I'd hate to end up reducing, rather than increasing, the "apparent
impedance" of my headphones by 5x, to appear as less than 2 ohms, and fry
the amp on an expensive MP3 player...


That's not how it works. Worst case would be that the iPod sees the 8
Ohm (so there may be a voltag drop) and the headphone is, kind of, twice
as far away. Nothing will break, however.

BTW: did you ever connect the headphone?? What happended?

Stephan