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Good Music Good Music is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player

Question: Impedance matching:

How can I make an adapter to allow connection of old 8 ohm headphones to a
modern personal audio source (MP3 player, etc) expecting the newer kind of
30-40 ohms or so (?) headphones?

Via google, I saw mention of using audio transformers for other impedance
matching applications: Are there such audio transformers that I could use
one for each headphone channel?

Or if that's not sufficient, where might I find plans for whatever kind of
battery-powered IC circuit I may need to build to perform this function?

(Replacing the original 8-ohm drivers in the headphones is not an option for
this application.)

Thanks in advance,
- Goodmusic




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



Good Music wrote:

Question: Impedance matching:

How can I make an adapter to allow connection of old 8 ohm headphones to a
modern personal audio source (MP3 player, etc) expecting the newer kind of
30-40 ohms or so (?) headphones?

Via google, I saw mention of using audio transformers for other impedance
matching applications: Are there such audio transformers that I could use
one for each headphone channel?

Or if that's not sufficient, where might I find plans for whatever kind of
battery-powered IC circuit I may need to build to perform this function?

(Replacing the original 8-ohm drivers in the headphones is not an option for
this application.)


Don't even bother. Many headphones claiming to be 8 ohms aren't anyway !

Just connect it and see if it sounds ok. You won't hurt anything and in any case
a new pair of headphones will be the cheapest and best option if you're not
happy with the results anyway.

Graham

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Good Music Good Music is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player


Don't even bother. Many headphones claiming to be 8 ohms aren't anyway !

Just connect it and see if it sounds ok. You won't hurt anything and in
any case
a new pair of headphones will be the cheapest and best option if you're
not
happy with the results anyway.

Graham


Thanks Graham, but I'm actually pretty intent on finding a way to
specifically use this specific old set of 8-ohm headphones, though I don't
want to "short out" my expensive MP3 player's amp. The reason is these were
my grandad's headphones - I just like them and am set on using them,
whatever kind of adapter I have to make :-)


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[email protected] westpase-he_ac@hotmail.com is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player


Good Music wrote:

Don't even bother. Many headphones claiming to be 8 ohms aren't anyway !

Just connect it and see if it sounds ok. You won't hurt anything and in
any case
a new pair of headphones will be the cheapest and best option if you're
not
happy with the results anyway.

Graham


Thanks Graham, but I'm actually pretty intent on finding a way to
specifically use this specific old set of 8-ohm headphones, though I don't
want to "short out" my expensive MP3 player's amp. The reason is these were
my grandad's headphones - I just like them and am set on using them,
whatever kind of adapter I have to make :-)


Perhaps you could find the receiver that your grand dad used and
and feed your MP3 player into it on an AUX. input.
Headphones have the right feed and player sees a load.
JMTCW

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Arny Krueger Arny Krueger is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player


"Good Music" wrote in message
m...

Don't even bother. Many headphones claiming to be 8 ohms aren't anyway !

Just connect it and see if it sounds ok. You won't hurt anything and in
any case
a new pair of headphones will be the cheapest and best option if you're
not
happy with the results anyway.


Thanks Graham, but I'm actually pretty intent on finding a way to
specifically use this specific old set of 8-ohm headphones,


I guess someone needs to reiterate Graham's advice: Try it before you raise
a giant dust cloud trying to fix a problem that may not be there.

The headphones may not actually be 8 ohms, since 8 ohms is a very common
nominal figure. Just about every headphone and speaker that is rated at 8
ohms isn't exactly 8 ohms. Most miss 8 ohms by a mile or two.

Your source may not be problematical at all if the moon were blue and the
headphones were actually 8 ohms.

though I don't want to "short out" my expensive MP3 player's amp.


8 ohms isn't excatly a short for a headphone amp. Headphone amps are
generally designed to handle shorts without being damaged.

The reason is these were my grandad's headphones - I just like them and
am set on using them, whatever kind of adapter I have to make :-)


First try the simplist solution of all - see how they work in real life.




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Eeyore Eeyore is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohmheadphones to modern MP3 player



Good Music wrote:


Don't even bother. Many headphones claiming to be 8 ohms aren't anyway !

Just connect it and see if it sounds ok. You won't hurt anything and in
any case
a new pair of headphones will be the cheapest and best option if you're
not happy with the results anyway.

Graham


Thanks Graham, but I'm actually pretty intent on finding a way to
specifically use this specific old set of 8-ohm headphones,


Do you know that they actually measure 8 ohms ?


though I don't want to "short out" my expensive MP3 player's amp.


It's *very* unlikely that'll happen. The internal amp produces such a tiny
amount of power that it won't be bothered.


The reason is these were
my grandad's headphones - I just like them and am set on using them,
whatever kind of adapter I have to make :-)


Any adapter using a transfomer will alter the sound anyway.

If it's really important, an external buffer amp will be best.

Graham


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Good Music Good Music is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player

Thanks Graham, Arny, Dave, & Stephan -

Ok! "Survey Says," connect the phones directly!

When I pick up the 1/8" L-shape replacement plug tomorrow, I'll also just
grab a couple 10-ohm resistors & see how the phones sound with & without,
and if there's no major sound difference other than slight volume drop, will
use them with (even if that means I'm "stuck on stupid" (Stephan, I
saved your info on transformers just incase.)

Thanks,
- Goodmusic

"Eeyore" wrote in
message ...



Good Music wrote:


Don't even bother. Many headphones claiming to be 8 ohms aren't anyway
!

Just connect it and see if it sounds ok. You won't hurt anything and in
any case
a new pair of headphones will be the cheapest and best option if you're
not happy with the results anyway.

Graham


Thanks Graham, but I'm actually pretty intent on finding a way to
specifically use this specific old set of 8-ohm headphones,


Do you know that they actually measure 8 ohms ?


though I don't want to "short out" my expensive MP3 player's amp.


It's *very* unlikely that'll happen. The internal amp produces such a tiny
amount of power that it won't be bothered.


The reason is these were
my grandad's headphones - I just like them and am set on using them,
whatever kind of adapter I have to make :-)


Any adapter using a transfomer will alter the sound anyway.

If it's really important, an external buffer amp will be best.

Graham




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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:
Question: Impedance matching:

How can I make an adapter to allow connection of old 8 ohm headphones to a
modern personal audio source (MP3 player, etc) expecting the newer kind of
30-40 ohms or so (?) headphones?

Via google, I saw mention of using audio transformers for other impedance
matching applications: Are there such audio transformers that I could use
one for each headphone channel?

Or if that's not sufficient, where might I find plans for whatever kind of
battery-powered IC circuit I may need to build to perform this function?

(Replacing the original 8-ohm drivers in the headphones is not an option for
this application.)

Thanks in advance,
- Goodmusic




Have a look at www.mouser.com and look for 'audio transformer'. And
don't be surprised about some of the prices :-)
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Good Music Good Music is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player

More questions:

From: "Stephan Gipp"
Have a look at www.mouser.com and look for 'audio transformer'. And don't
be surprised about some of the prices :-)



Thanks, I see them. But, I'm not sure how to choose one for my application;

_HELP_?:

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?

Or is there more to it than that? (I'm a total beginner in electronics)
For instance, I don't know if maybe I need to calculate the RATIO of
impedances I want, like 8:40 -- 1:5, and get a transformer with 5 times as
many windings on the secondary coil as the primary, or some other such
intermediate calculation...

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?

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...

Thanks,
- Goodmusic


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Dave Dave is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player


"Good Music" wrote in message
m...
and fry
the amp on an expensive MP3 player...

One more voice: YOU ARE NOT GOING TO FRY YOUR AMP. MP3 players are, for
the most part, designed for use by teenage kids who do things like stick
paper clips in the headphone jack. The power generated by your player is
miniscule compared to the power ratings of the vast majority of output
transistors.

If you are that concerned why don't you put a 20-ohm resistor in series with
each headphone lead. Total cost maybe 50 cents.




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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
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JANA JANA is offline
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Default Question: Impedance matching: adapter for onnecting 8 ohm headphones to modern MP3 player

Your best and cheapest and easiest option is to buy a good quality 30 ohm or
greater impedance headphones.

If you start messing with transformers, and or amplifier circuits, then you
start getting in to having to carry around more equipment, and also
batteries to run the add-ons. This is not practical. Also, adding
amplification, or devices will start to degrade the sound quality, unless
you spend a fair amount, or you spend a lot of time to design and test what
you build.

--

JANA
_____


"Good Music" wrote in message
...
Question: Impedance matching:

How can I make an adapter to allow connection of old 8 ohm headphones to a
modern personal audio source (MP3 player, etc) expecting the newer kind of
30-40 ohms or so (?) headphones?

Via google, I saw mention of using audio transformers for other impedance
matching applications: Are there such audio transformers that I could use
one for each headphone channel?

Or if that's not sufficient, where might I find plans for whatever kind of
battery-powered IC circuit I may need to build to perform this function?

(Replacing the original 8-ohm drivers in the headphones is not an option for
this application.)

Thanks in advance,
- Goodmusic





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