I did own a Sunray Pro Gold headphone and the first thing I noticed with my GPX 5000 was some type of feedback (like a hum) in the background within my threshold. I tried different threshold levels on the detector including lowering both volume controls on the headphone however the feedback within the headphone still existed. Now what I had noticed is the feedback seems more pronounced when I move closer to the coil HOWEVER when I checked to see if the headphones I had previously been using had a similar type of feedback, then none existed. I use an extra-long detector shaft and being 6 foot tall the headphones should be well out of range of the 18" mono coil I was using.
Another re-test to see if I can isolate the problem I found to my surprise I could hear the same audible feedback sound in the headphone BUT this time even before I plugged the headphone into the Detector. As I moved the headphone closer to the Detector Coil the feedback became louder BUT reduce in volume the further I moved away from the Detector Coil. I again tried turning the Volume controls on the Headphones to their lowest setting but the feedback was still audible. Now once I stood up at the height I would normally be detecting at the feedback was not as audible. Once I switched the Detector off the feedback ceased.
I did e-mail Sunray from their website in the US in regards to my findings and this is what they said:
" I tried the stock Minelab headphones and the same thing happens but not near as loud as the Pro Golds. I am sure that the larger the coil the greater distance they would be picked up also. I also, tried a pair of Detector Pro Gray Ghost HP and they do the same thing and about as loud as the SR Pro Golds as they use a speaker similar to the Golds. However, The Pro Gold headphones are one of the most popular headphones used on the GPX detectors in this country and I have never heard a complaint about that feedback issue. There is nothing wrong with the headphones and I have heard that feedback noise for years if I move too close to the coil with my headphones when retreiving the target."
Now the headphones I have been using have an impedance of 32 ohm and it does not experience this type of feedback.
Another re-test to see if I can isolate the problem I found to my surprise I could hear the same audible feedback sound in the headphone BUT this time even before I plugged the headphone into the Detector. As I moved the headphone closer to the Detector Coil the feedback became louder BUT reduce in volume the further I moved away from the Detector Coil. I again tried turning the Volume controls on the Headphones to their lowest setting but the feedback was still audible. Now once I stood up at the height I would normally be detecting at the feedback was not as audible. Once I switched the Detector off the feedback ceased.
I did e-mail Sunray from their website in the US in regards to my findings and this is what they said:
" I tried the stock Minelab headphones and the same thing happens but not near as loud as the Pro Golds. I am sure that the larger the coil the greater distance they would be picked up also. I also, tried a pair of Detector Pro Gray Ghost HP and they do the same thing and about as loud as the SR Pro Golds as they use a speaker similar to the Golds. However, The Pro Gold headphones are one of the most popular headphones used on the GPX detectors in this country and I have never heard a complaint about that feedback issue. There is nothing wrong with the headphones and I have heard that feedback noise for years if I move too close to the coil with my headphones when retreiving the target."
Now the headphones I have been using have an impedance of 32 ohm and it does not experience this type of feedback.
