Coils for the QED

Prospecting Australia

Help Support Prospecting Australia:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Mark, 45 or 50, it doesnt matter as its just a number. Your null at 45 will be no different to my null at 51 (which originally was 50)
Just an update on EMI with the Sadie. I spoke with Howard and he said the QED was designed for use with the speaker, so with headphones youll hear every little wobble from ground noise and EMI. I can definitely hear it far more through headphones than the external speaker. To run comfortably THS B needs to be to be set at, or close to null and THS A turned down until comfortable. My Sennheiser HD25s have good dynamic range and seem to be super sensitive to every little noise. I tried running with the external speaker today and it was a much quieter, more stable experience although I feel conspicuous chirping my way through the bush.

If youre experiencing EMI and wondering whether its caused by the coil or machine, Howard said disconnect the coil from the machine and listen if youve got a clean threshold without it. If youve still got a noisy threshold, its internal EMI, which means youve probably got dry joints on the PCB and you should book it in with him to resolder them. If the threshold is clean without the coil, but noisy with it connected, its just the coil acting as an antenna and picking up surrounding electromagnetic signals as youd expect. My machines threshold is nice and flat when disconnected, so the EMI is being picked up from the Sadie, which is a relief, but I need to figure out the best settings for use with my headphones so I can hear tiny target signals within the surrounding noise.

Howard also said that a few people have mentioned that theyre experiencing higher than usual EMI lately. Hes not sure why, but perhaps its something to do with Elon Musks increased activity in space. Im actually wondering if it has something to do with the new solar cycle? Either way, not great news for quiet running machines.

(@ Aussiedigs, Howard said the same as you - that the number on the screen for null is irrelevant as long as youre able to null so 45 it is on mine. ?)
Thanks for the update.

Interesting that there is a threshold at all when the coil is disconnected. I just thought there would be nothing, although have never really thought about it.

Ive had the Detech Ultra Sensing coil out on mine several times in the past few weeks and no EMI issues. Ran Mode 1, Gain 10 for a while today with no trouble. Dont think its Elon ;)
I know exactly what you mean by the difference between using a sensitive set of earphones vs an external speaker on the QED. Even though the Logitech X50 is louder it is even less sensitive than the original QED external speaker (Nokia MD11) but using either of those external speakers is like having squelch turned right up on a CB radio - you need a fair signal to hear anything. Pretty much any headphone is more sensitive but even the sensitivity difference between various earphones/headphones can be amazing.

I know that a wobbly threshold with little spikes can be fatiguing and distracting but by using the X50 external speaker you are losing a lot of the information the QED is telling you - especially info about faint targets.

As Howard has said in other forums, when passing over a target you get a pitch change way before you get the volume change and that pitch change can give you upto 30% deeper on small targets. I have tested it & its true so I have actually been trying to amplify the faint signals and just accept any threshold stability loss.

I have a box of old earphones & tried out about 20 pairs of various audio earphones ( sennheiser, bose, no name) & 6 pairs of headphones ( UR-30, Sunray Gold Pro, DC H10-13.4..) and the best by far was a noname one followed by KZ-ZST earbuds.

I also got a very cheap & light, long lasting headphone amp that I velcroed to the side of the QED. From a hifi perspective it is a truly crappy amp but perfect for lifting the sound level of the threshold just enough for my liking.

Personal choice - set up for beep & dig or set up to listen to the light sabre like whoo-whoo and figure out what it is telling you. Either way it's pretty good.

Reg Wilson said:
Aussiedigs, I am in the process of putting together a test patch on my property (on which I have detected gold) and will be able to post some comparisons with not only different coils, but also different detectors. I will post results as they become available.

There have been some results by Reg on another forum.
Has anybody here found good gold with the QED?
I am cinsidering getting a QED . People posting here seem to be having issues with the machine. True or false or mainly finger trouble??
Adrian ss said:
Has anybody here found good gold with the QED?
I am cinsidering getting a QED . People posting here seem to be having issues with the machine. True or false or mainly finger trouble??
90% of Qed users are posting finds on facebook, more of a look at me thing and how many likes did I get. Alot of gold pictures have been posted last 12 months Adrian.
Thanks for the pics. Nice.
Nothing much wrong with the sensitivity aye?
Have been stewing over the QED for quite a while now. I don't like reading about bad solder joints though and that should not be happening now that the machine has been in production for some time. Plenty of time to practice and master high reliability soldering techniques.
Still like to give one a go but.
I reckon there are a few users in the canberra region now to give you a play with one, il get back to you with some numbers later today. True about the solder joints though.
Adrian if you look up Bazz that makes the crack scratchers for sale on here, he is in you neck of the woods and is a great guy. Im sure he would let you have a play with his. His user name here is Sandbagger.