Bipolar PI MD with GB and DD Coil

[GeoMax]

Interesting… The PCBs in the pictures are original boards. There were several buyers of these circuit boards from Bulgaria. Perhaps one of them offered one of their spare boards. Since it's an original set of circuit boards, I see no problem in reselling it.

Some more original PCB sets are available for sale here:

https://www.ebay.de/itm/128066898667?

[Detectorist#1]

Hi,
Additional information for the people assembling "Dual Tone Pulse Detector Rev.B":
1. Used search DD coil haves bridge connection in female connector between pin1 and pin5. This wire bridge have to be cutted.
2. The noise outside the buildings is lower than inside the buildings. This allows to increase amplifying of second RX stage by changing of the value of RT1 from 20K to 100K.
3. The removing of the capacitor C6 (1uF 63V) and making of short connection instead this capacitor haves as result more clear sound with reduced opposite tone after the target's indentification.

[algan]

Orbit was right:




Trading in this product began...
https://metaldetecting.eu/index.php/...cseen.html#new

Look colleague boilcoil, I bought two shipments from GeoMax, but I’m busy with other things right now. I posted the ad in case another colleague wants them and has the time to apply them.I’m offering them at the same price I paid. What kind of "trading" are you accusing me of?

[GeoMax]

Hello everyone,

That's right, Algan was one of the buyers from Bulgaria who purchased two sets of circuit boards. I have no problem with him reselling the boards.

[boilcoil]

My mistake; I thought that active trading of the product was actually beginning.
I apologize to Algan and Geo Max.

[GeoMax]

Hi Boilcoil,

No problem. Anyone can create their own PCB using the published schematic. The schematic and all values are absolutely correct. However, it's not entirely easy to create a good design for a well-functioning PCB, as some traces are delicate and need to be routed precisely. To be honest, we needed about five different approaches to place the components and route their signals in such a way that no noise interferes with or can occur in the circuit. The circuit is very sensitive and requires a good PCB design. A set of two boards (main board and battery board) for this project is available on eBay.

[PahWiz]

Awesome project—congrats to Detectorist#1 and Geomax! You can tell a lot of work went into this, and it’s clearly a labor of love. Thanks for sharing it with the community—great job, and good luck!

One small request, though: the schematic in post #189 is a PNG, and the details and notes are pretty hard to make out—especially when you zoom in, the labels and fine lines get blurry/pixelated. A PDF version of the mainboard schematic would be much easier to read, since the text, component values, net names, and notes would stay sharp and be easier to zoom in on, print, or reference while building. If you could upload the mainboard schematic as a PDF, that would be awesome—and totally understand if that’s not doable. Thanks a lot!

[GeoMax]

Hello everyone,

When viewing a PNG file on a mobile device, the resolution isn't optimal. However, this isn't due to the PNG file itself.
Here's a high-resolution (1200 dpi) schematic diagram as a PDF.

Dual Tone Pulse Detector Rev B (28.07.2026)(1200dpi).pdf
Power Board with Charger Rev.D (1200dpi).pdf