Ok to run high-end headphones with amp output?

[The Paulinator]

I was recently told that my top-of-the-line MB Quart headphones would probably sound better (because of my Sony receiver's weak headphone amp) if I wired a 1/4" female headphone jack to the 'B' left and right outputs of my reciever. Apparently the ohm load the headphones put on the amp lowers it's output significantly and will not damage them, and the perceived output relative to the volume knob will be pretty close to how it is using the headphone jack.

Is this fact or fiction??

[mjarve]

I've blown up many a fine set of cans trying that... Many mass-market receivers seem to run the phones off the speaker outputs anyways, with a set of substantial resistors in series. You might want to try it that way.

[ultrachrome]

I can't really answer your question but Rod Elliot's Headphone Adaptor for Power Amplifiers may shed some clues.

[maylar]

Normally, headphone outputs are taken right from the speaker output circuits on an amplifier, with 220-330 ohm resistors in series with them. Without the resistors the volume control is really touchy, since they need very little voltage to operate.

Headphone impedances range from 32 to 300 ohms nowadays. The series resistor may be different for optimum volume control resolution with different impedances.

Whether it'll sound any better than through the headphone jack you have? Just gotta try it and see.

[lucpes]

You may want to try building one of these. By using low value resistors (forming a voltage divider) you can keep a good ratio between amp out impedance (keep it smallish!) / headphone impedance.

[sreten]

If your headphones are high impedance this is indeed true.


sreten.

[The Paulinator]

These are 300 ohms per side, would any resistors really be necessary? I tried to run it the way that picture shows, but without the resistors, but there was a short somewhere. The volume was about what I would expect with the knob at that position if I were using using the headphone jacks, but there was a short somewhere in my solder connections (I knew it was a short because one side was louder than the other) and after about 5 or 6 seconds the amp went into protect mode.

[Steve Eddy]

Why not just build yourself a dedicated headphone amplifier? There's a bunch of them to choose from on the projects page over at http://www.headwize.com.

se

[destroyer X]

This way i burn the last "neuronium" i had to use.

You near to turn crazy!..... if you found a completely flat audio point inside your amplifier..... put their an good capacitor... two for stereo of course..... ihhhhhh!....my last neuronium is almost dead!!!...... lets run fast till he died!..... and construct an small class A amplifier that uses batteries and the headphone voice coil connected in series with the colector.....put also an emitter resistor, this way if your transistor became shorted (very difficult to happen that) the amount of current will not burn your headphone.... this way..... "a direct drive, flat, and class A amplifier in a very good headphone" will send you to heaven.... the quality you will hear will make you trow your speaker out off the window and to saw you big and complicated amplifier or to use it as a heater generator to cold mornings!

This way you be thinking why so big technologies..... why so big expenses of money..... why so much power?....... that's all those things will appear stupid for you and you will became a sad and unhappy person...

I think............ aaaaah!...... its burning last functional 52 years old last neuronium!.......better not do do!......you will look to yourself in the mirror and will think that's a crazy world!

Carlos, the destroyer X likes you

[peranders]

I think the best solution is to have a separate headphone amp with low gain, low noise, low distortion, low everything. In some cases you can connect the headphones directly to line out if the headhone has rather high impedance and/or the output has good drive capability.