High Impedance Headphones Improve Depth on TDI SL

[XLOOX]

When I first got my TDI SL I used an old pair of 32 Ohm Shure hifi headphones. Worked fine but cord was a bit short when trying to put the detector on the ground. Last year up in Clermont, from OBP , I got a pair of 100 Ohm Koss UR30 Minelab SDC headphones terminated with a 6.5mm right angle plug. Nice long cord & definitely clearer, louder sound but the earphone pads really dont like DEET insect repellant !

Reg Sniff mentions in another forum (cant remember which one) that in order to get a louder headset for the TDI he built a set of 600 ohm earphones that were so loud he needed to add a volume limiter. I have never had any trouble with the volume from the TDI SL but figured that a set of really high impedance headphones might add a bit to detection depth if it could bring out the fainter signals.

So I ordered a set of 320 ohm HP320 earphones from "tosound" on ebay. Not cheap at $110, but I am glad to say they make a HUGE difference.

For small targets the depth only increased a little (1grain Au from 60mm to 70mm, 0.5g au coin from 165mm to 180mm ) but pennys & 50c pieces gained 30-40mm extra depth & massive iron gained a whole 60mm. Even better, now if the signal is enough to break the threshold then it it is automatically loud & clear.

Note that I have mainly done air tests (using Eric Fosters method) but no reason that the directional differences wouldnt be repeatable in ground. I did run a couple of ground tests and they just backed up the air tests.

I am very excited about the clarity & depth gains but there are some negatives:
1) a close target is REALLY loud. Not actually painful but definitely makes you jump.
2) The SL silent threshold is no longer silent but a high frequency mozzy whine. Unsure how I will like this after a few hours detecting
3) ground noise is more noticeable
4) has old style 15mm diameter in-ear disks that are more likely to fall out than in-canal buds or over-ear headphones.
5) short straight cord (1m)
6) 3.5mm plug

I can fix the last 2 with a 3.5mm-6.5mm coiled extension cord and come winter I'll be giving them a go in the field but until then I am really interested in hearing others TDI SL headphone / booster experiences.

 

[karelian65]

When you get that fine mozzie whine you know the audio is as good as it gets. The ability to cut peripheral noise out in the bush or on the beach translates into extra depth.
There is a reason nugget hunters use either good headphones or an amplified external speaker. When you look at how much we invest in our detectors, coils, accommodation and fuel costs etc .. A good set of headphones is a bargain, with significant benefits in our ability to pick up on whispers etc. In the past I used the old Garrett headphones, Sony and now the Koss UR30 and Sunray Pro Gold.

All a worthy investment. Some headphones have a sound limiter to stop your ears being blown up...
All the best, Karelian

 

[karelian65]

Nokia MD-11 is a great alternative to headphones if the weather is hot and sunny. Uses a 3.5mm plug, AAA batteries and is very loud.. simple on off button only..
Easily mounted on the detector as shown or under the arm cuff. So light is doesn't alter the weight or balance of the machine. If audio overloads the speaker cuts out and needs to be restarted. It does not have a volume control so it can be too loud in public areas but works great out in the bush. When my brain is cooking and the sun is doing its worst the wide brim hat comes out and the headphones go back in their box.. only then do I use the amplified speaker. Headphones are still my first choice since they cut out external noise as well which is important when I work the beach..
Karelian

 

[XLOOX]

Hi Karelian,

Those Sunray Pro Gold seem like the goods -volume controls, volume limiting switch, long strong cable with 6.35mm right angle plug & 150 Ohm so should be loud.

At same TDI SL settings is the Sunray Pro Gold noticeably louder than the Koss UR30s? Is the "mozzy whine" clear ?

 

[karelian65]

The Sunray Pro Gold is feature rich, better quality and the audio is very clear. Because both the Sunray and Koss are good quality it is hard for me to say which has the technically better audio, but without test results I'd say the Sunray is better. Because the Tdi SL does not have volume control I'd go the Sunray every time.
My Pro has volume control so it matters less which of the two I use on that machine. Both are excellent, but the Sunray has all the features that matter when using a metal detector, plus the quality of materials etc is clearly better.. Sunray keeps ambient noise out a bit better as well, the Koss has a slightly larger ear muff, perhaps a fraction more comfortable for big ears like mine. Sunray is pricey but I'm very pleased with mine. The volume limiting feature is most welcome and much appreciated, there is rarely a detecting day that does not involve a few blasts from shallow iron etc
Karelian

 

[XLOOX]

Thanks Karelian, that is a great review.

Sunrays seem like a clear winner there but if the audio volume & clarity isn't significantly better than the Koss then I need to keep looking for now as the HP320 earphones audio is MUCH louder & clearer than my Koss, it is just that HP320s aren't built for prospecting.

I might be on a hiding to nothing though as I see that most of the specialist detector headphones ( Nugget Buster, Black Widow, Gray Ghost, Sunray) are all 150 ohm.

If I cant find a sturdy set of 300 Ohm headphones I might just have to try & ruggedize the HP320s... or maybe get a booster.

Has anyone used one with the TDI SL?

 

[uttu kaos]

Gday all, ill just but in here for a second..Where abouts do you get the Sunrays from Karelian, i cant find a stockist at all for them..i want a set for my tdi sl..

 

[karelian65]

Ebay, Texas Premium Detectors, $230 delivered.. Can't find a local seller. Reeds Prospecting in Australia sells lots of headphones but didn't see Sunray Pro Gold.. Karelian

 

[Ridge Runner]

Grey Ghost, or Nugget Buster and the other models made by Detector Pro and SunRay are the best Detecting Headphones Bar None,

Koss Headphones Colour the Sound adding too much Bass and can cause faint targets to be missed, But the down side to the models above is they have absolutely Terrible sound when it comes to listening to Music,

The Grey Ghosts have the Limiter and the Nugget Busters Do Not have the Limiter, But even with the limiter I have still had my Ears blasted when I have swung the Coil over a buried Plough Blade just below the surface, And when you are in the Zone Signals of that Volume can scare the life out of ya.

J.

EDIT:- I have found a good Dealer that has most of the Detector Pro Headphones in Stock that I can get if people have trouble getting hold of them.

 

[Hamid]

Thank you for sharing :gemstone: