PULSESCAN AUDIO QUESTION

[daverave]

took the pulsescan for its first outing to the beach a few hours ago and found some coins...my wife in the photos with the pulsescan.

[dbanner]

one simple thing to try daverave, I saw this on another forum somewhere, try running the coil cord straight up the stem until about half way before wrapping around stem. Its worth a try?

[Orbit]

What are you using at the exit? If you use 386 he himself produces noises !It's such a design pcb ...noise is expressed in the headphones something less is noticed in the speaker !

[daverave]

i didnt use a 386 amp instead i used a small transformer which boosted the audio to my piezo headphones...i did a test without the transformer and the noise problem was still present....at the moment the noise problem has beaten me...but its lower now with the 1000 uf cap across the supply....we are also using blue tooth audio which has worked ok with the pulsescan.

[daverave]

one simple thing to try daverave, I saw this on another forum somewhere, try running the coil cord straight up the stem until about half way before wrapping around stem. Its worth a try?

the noise problem is still present even with the coil disconnected.

[Orbit]

i didnt use a 386 amp instead i used a small transformer which boosted the audio to my piezo headphones...i did a test without the transformer and the noise problem was still present....at the moment the noise problem has beaten me...but its lower now with the 1000 uf cap across the supply....we are also using blue tooth audio which has worked ok with the pulsescan.

When disconnecting audio and the noise disappears in this case the noise originates from the oscillators it will help more capacity ESR I did not notice it removes noise .The noise is also increased due to increased profits one channel or mode all metal geb mod .

[daverave]

When disconnecting audio and the noise disappears in this case the noise originates from the oscillators it will help more capacity ESR I did not notice it removes noise .The noise is also increased due to increased profits one channel or mode all metal geb mod .

im not entirely sure what you mean...could you explain more precisely.

[Orbit]

im not entirely sure what you mean...could you explain more precisely.

Write me a mail to explain !

[qute1]

Try this, needs 3v (2xaa or aaa) https://www.ebay.co.uk/itm/PAM8403-D...K/222941230089 but solved noise problems on several radio recievers that were Noisy and removes the inductor coupling issues from the equation..

[dbanner]

i didnt use a 386 amp instead i used a small transformer which boosted the audio to my piezo headphones...i did a test without the transformer and the noise problem was still present....at the moment the noise problem has beaten me...but its lower now with the 1000 uf cap across the supply....we are also using blue tooth audio which has worked ok with the pulsescan.

You mentioned Bluetooth headset, I'm assuming the transmitter has its own supply, or are you powered from detector supply? I would like to try this on one of my machines. The sound you described, is it a hum or is it a tic tic sort of sound? I also noticed your plastic box. Did you do this yourself. Have you promised someone not to post photos of pcb?

[daverave]

yes blue tooth transmitter and receiver headphones have their own power supply....the plastic box i bought secondhand some years ago and never used it until now...i have made it weather and surf wet sand proof...when i scoped the power supplies i can see the tx pulse train..but its reduced now by the extra capacitor.

[dbanner]

There is one thing I noticed on some pi schematics, a small inductor( between 47uH and 100uH placed in line with power supply rail. You see it on xl 500 schematic and also on ppd1 schematic. I think this is done for ripple( noise) suppression.
Let us know when you score a ring on the beach with this machine.

[daverave]

There is one thing I noticed on some pi schematics, a small inductor( between 47uH and 100uH placed in line with power supply rail. You see it on xl 500 schematic and also on ppd1 schematic. I think this is done for ripple( noise) suppression.
Let us know when you score a ring on the beach with this machine.

i can see those inductors that you mentioned in the schematic....it bought to mind a diagram i saw some years ago of the front end of the garrett atx and if my memory serves me right it also had a inductor in the circuit.

[dbanner]

Yes, in the case of the ppd1 and xl500 circuits, it is used to suppress noise coming from power supply boost circuit and from the coil tx coming back to the supply rail.
Have a read here also
http://treasurehunters.co.za/forums/...nter-solution/
I don't think this makes any difference at all.

[daverave]

hi dbanner....i looked at your link and this noise problem is much more common than i thought even in garrett pulse detectors...its interesting cause i can hear my search coil resonating quite noticeable...but ive got the back ground noise down to as low that i can for now.