VLF no name

[dbanner]

Does anyone have more info on this device? I can't seem to find it again. I think it is here on the forum. The reason for my interest is I noticed the simplicity of the power supply circuit and the audio oscillator. Overall, the circuit looks pretty straightfoward. It looks to be operating at around 6kHz according to some data on the schem. Coil winding data is included as well.

[Nandor]

I think it's ALL-1.

[Gwil]

The schematics look very different to me.

[Funfinder]

Its some older Fisher, perhaps 12xx.

[kt315]

I think it's ALL-1.

ALL-1 is based on fisher 553 or 555. this is a hybrid - white classic sch but 4066 were changed on JFETs.

[nejdet]

Detector ''Moharem'' from Bulgaria....

[kt315]

Detector ''Moharem'' from Bulgaria....

we had discussed it about. when somebody says its new it is just old forgotten.

[dbanner]

It looks to be very conventional circuit. Probably works as good as any similar circuit. Thanks everyone for your replies.

[6666]

Interesting simple circuit, I wonder what would be the minimum vlf circuit you could add a micro based vdi to ?

[waltr]

Interesting simple circuit, I wonder what would be the minimum vlf circuit you could add a micro based vdi to ?

The simplest is everything up to the last comparators where you pick off the 'X' & 'Y' signals (like on the IDX & TGSL VDI threads). A simple processor then can do VDI and audio.

More complex in the processor could eliminate the GB & Disc and sampling circuits by directly digitizing (ADC) the TX and RX signals.
The only analog circuits needed are the power supplies, the TX oscillator and RX preamp.
Then all is done within the processor.

[timekiller]

*Relax* detectors these are the new moxarem ...so I guess

[kt315]

DB has to be learning search engine of the forum. this forum speaking on clear english.
i do not speak english, not my native, so why english speaking men are not able to use search knob in their native forum?
moharemka 2005 year https://www.geotech1.com/forums/show...-bulgarian-VLF

please do not write in a header NONAME. write BULGARIAN, MOHAREMKA etc. - hard to search at future time.

pleasure

[6666]

The simplest is everything up to the last comparators where you pick off the 'X' & 'Y' signals (like on the IDX & TGSL VDI threads). A simple processor then can do VDI and audio.

More complex in the processor could eliminate the GB & Disc and sampling circuits by directly digitizing (ADC) the TX and RX signals.
The only analog circuits needed are the power supplies, the TX oscillator and RX preamp.
Then all is done within the processor.

Thanks, could be worth experimenting with on an old machine

[dbanner]

How about just a single LED which lights for targets whose phase is in the silver range. In other words, the LED fires above a notch treshold.
Without the addition of a third channel, some simple implementation with an LED, if that is at all possible. When the LED fires, you dig. That way you only dig possible silver targets, on days you don't feel like digging everything. A simple detector modified for hunting just silver.
The effort of doing a micro VDI maybe too much, better off just buying a good detector with a VDI.
Surely someone can design a simple phase summing/difference amplifier with an LED set above a certain threshold using just a dual opamp chip and couple of transistors.

[kt315]

DB i offer two LEDs - one on the gold, Red Color, another on silver, Blue Color.