IDX-PRO+VDI

[Koala]

VDI
https://vk.com/video-33752123_456239989

well done. Working well.

[gurdal]

Thank you very much koala;
I want to add minelab vco sound if technically possible.
Nobody shares information about this topic

Best regards

[liekwang]

https://www.geotech1.com/forums/show...ight=VCO+audio

[SWL]

liekwang --- It is for PI

[dbanner]

Try this circuit, it is taken from Cscope 1220b metal detector. Nice vco sound.

Look for the complete vco circuit (the audio amp is missing from the ltspice circuit) by searching for the 1220b schematic here on the forum. I'm will show you how to do he circuit is connected to the rest.

[tomec123]

Hello everybody. I'm actually the silent reader here, but I would have a question for people who know what they're doing. I have now set up 2 IDX and actually they run quite well. (at least with the original Blue Max spool) I have now also bought the Fischer CZ spool as described at the beginning of this treats. However, the ground leveling cannot be achieved with this. No setting is effective and the noise is terrible. (both when swiveling it beeps constantly and when "pumping") Purely from the air test values, this coil may be better than the original Whites, but they are not really usable in practice. Does anyone have an idea where you could change something to make the ground balance a little less sensitive? ...

[gurdal]

Try this circuit, it is taken from Cscope 1220b metal detector. Nice vco sound.

Look for the complete vco circuit (the audio amp is missing from the ltspice circuit) by searching for the 1220b schematic here on the forum. I'm will show you how to do he circuit is connected to the rest.

Thanks dbanner

[Koala]

Hello everybody. I'm actually the silent reader here, but I would have a question for people who know what they're doing. I have now set up 2 IDX and actually they run quite well. (at least with the original Blue Max spool) I have now also bought the Fischer CZ spool as described at the beginning of this treats. However, the ground leveling cannot be achieved with this. No setting is effective and the noise is terrible. (both when swiveling it beeps constantly and when "pumping") Purely from the air test values, this coil may be better than the original Whites, but they are not really usable in practice. Does anyone have an idea where you could change something to make the ground balance a little less sensitive? ...

have you added any capacitors to adjust the frequency of the Rx Tx ?

[tomec123]

Yes of corse

[dbanner]

Have you got the data for the Fisher coil?

[tomec123]

Yes, of corse
RX 38,6Ohm 11,1mH
TX 4,9Ohm 2,5mH
calculated cap data for the IDX is 104nF RX and 233nF TX. The deep is very good, but as I susriped bad groundbalance.
Iĺl tried 33nf / 0,33nf and 22nf / 0,33nf also...same result....no groundbalance possible.... :-(

[Koala]

RX-capacitor=33nF and TX-capacitor=330nF I believe ? for the Fisher coil

[dbanner]

Here's what you do.

First off, you are looking for a TX resonant frequency of 6590Hz(6.59kHz)
Tune the tx coil for this frequency.(whatever capacitance is required)

Next, you are looking for a RX resonant frequency of 4680Hz(4.68kHz).
Tune your Rx coil for this frequency.

If the ground balance is still off, then the phase shift at null is off.
One method for correcting this is to modify the ground balance circuit.

Simpler way is to put a feedback pot (100k) from one end of the TX coil to the RX coil( this is done on the back of the coil connector in the box. Adjust the pot until your phase shift at null is 90 degrees.(According to the dbowers idx coil build document).
If you don't have oscilloscope, then adjust the pot until the gb comes into proper range.

Remove the pot and measure the value and replace it with a fixed resistor.

[liekwang]

Try this circuit, it is taken from Cscope 1220b metal detector. Nice vco sound.

Look for the complete vco circuit (the audio amp is missing from the ltspice circuit) by searching for the 1220b schematic here on the forum. I'm will show you how to do he circuit is connected to the rest.

dbanner is there in this one who knows what transistor is used in cscope1220B audio
https://www.geotech1.com/forums/show...ighlight=1220B

[liekwang]

liekwang --- It is for PI

yes for pi but i haven't tried whether it can be used I highway it can be used for idx but who knows what the tone will be like