Head phone question

[joecoin]

I must clarify something here before I get in trouble.

I measured the RESISTANCE of my headphones, not the IMPEDANCE. As FOD points out , they are not the same thing. However, I believe a static resistive measurement will give you enough info to make a decision.

In a purely resistive circuit, impedance = resistance. However, there are few if any practical purely resistive circuits AS FAR AS I KNOW.

Having said that, you measure the headphones unplugged from the unit. You set the meter to measure resistance (ohms). Place either probe tip on the very end of the plug, then put the other probe tip on the end of the metal plug closest to the wire end. If you have stereo headphones, you will have two small bands on the plug. The very tip of the plug below the first band will be one channel, the small area between the bands will be the other channel, the area between the second band and the wire end of the plug should be the common connection.

Here are some links:

http://www.teamrocs.com/technical/pages/resistance_impedance.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/imped.html

http://www.soundstage.com/gettingtechnical/gettingtechnical200409.htm


Photo showing the bands:

http://ec1.images-amazon.com/images/I/311GVXjInpL._AA280_.jpg

 

[Piero franchi]

Thanks for that

 

[Fishers Ghost]

If you calculate the impedance of a set of moving coil headphones at a range of normal human ear audio frequencies then the resulsts will be very close to the dc resistance value of the headphone voice coil.when the frequencies used are from 1000 to 15000hz therefore a rough estimate of the impedance of a normal set of moving coil headphones is going to be near as damm it to the dc resistance.

The best headphones I have used on my Sov were a set of no name 8 ohm jobs from Trash n Treasure for 5 dollars. Had to reset volume and threshold to quite a bit lower setting.

If your hp impedance is too high for your detector the max volume and frequency response will be noticably reduced.
If the impedance is too low you could overload the audio output stage of your detector.

 

[Fishers Ghost]

A bit more info re impedance and ML GP Extreme detectors.

Some info from ML:

100 Ohm Koss UR-30 headphones work very well. Other models between 60

 

[Jiminsandiego]

My sun ray pro golds seem to work very well with my gt, however I have not tried the other top of the line head phones. For me they are certainly plenty loud even turned way down. They also have a limiter switch, which lowers (and changes) the sound of the initial tone but does not lower (or change) the threshold tone. Without the limiter the initial tone is much louder than the secondary threshold tone, but with the limiter switch on the threshold tone is more equal in volume making it ( the threshold tone) easier to hear and utilize. They seem to be very well built, comfortable and block outside noise very well. They do get hot on a hot day though. I would have very much liked to try ten different top of the line head phones before I bought them but after some research I decided the sun rays were a good bet.
Jim