Magnum on steroids!

[Prospekteur]

@Tim....thank you. They are not available now on their page. They are marked as "coming soon". So i think they are available in the next weeks;-). Its good for people who dont want to work with SMD.......they are build for "old-school" soldering;-)

[Tim]

Newhobby.eu still has the 2 board Magnum TH (NH-2), with pre-wound coils for US$35. He (Violin) also has a Surf clone (NH-7), 2 Pic controlled units, a Delta Pulse clone, and more -all at VERY CHEAP PRICES.

[SVEN1]

I still have a whole pile of SMD Magnum PCB's made from Ivonics files that he claimed was a working unit. Think there is 10 in the drawer and I have the SMT parts. Looking at getting rid of everything cheap. I am not building this detector too busy with other projects. $50US plus shipping. PM me if interested.

[Prospekteur]

I want to build a mgnum vlf. I will buy a coil and build the rest at my own. Can someone post the link with the last good working PCB layout and partlist.
Is there only a SMD layout out there. SMD is new to me......does someone sell ready etched PCB?

Regards prospecteur

[Davor]

BTW, LM324 are not much of the opamps in regard to noise, but especially distortion. In the front end of a VLF detector you should use only low distortion devices, because otherwise you are promoting mixing of the air signal with target responses, and it results in great deal of masking.
A trick with 2k2 pull-down resistors in LM324 outputs may help fix its nasty crossover distortion, but it goes only so far. They should be avoided there. TL07x family is enormously better.

[Davor]

Why is the 'on' resistance of the 4053 important?

It is not, but charge injection is. It is a phenomenon where a short current spike is injected into a signal path, ergo charge injection, due to the digital nature of switching circuitry. In CMOS switches the charge injection is greatly reduced in comparison to simple FET switches by virtue of using complementary mosfets, so a positive charge injection is cancelled by a negative injection of a complementary transistor doing the same thing. However, due to the asymmetry of P and N type mosfets, the charge injection is not perfect, and it is different for various offsets of input signal. Some switches are better than the others, and some may be improved by playing with offset.
In this particular case I don't believe there is a real problem with switches. They are running in a cyclostationary switching mode, followed by a 16Hz LPF, so charge injections can't do much damage, and the only effect could be a slight offset. Nothing else.

[Hyena]

In Ukraine, so do business. Take someone else's name, rename it and give it away for one's own. Free customs, now European)))

And this is exactly the reason why I will never buy anything from Polland, even when you are our neighbors

[Hyena]

Decided to slightly reduce the size of the device, it turned out 2x frequency (the place for the capacitors on the board 18 - 8 (or what we want), the board under the gainta g1910, now on / off, tone and frequency - "buttons", the choice of frequencies is implemented via relays (like on 5 mask), the indication of operating modes is introduced, the microcircuit 4041 has been removed, capacitors have a choice of ceramics or film ...

Schema? If not, all your posts should be in buy-sell-trade...

[Koala]

Decided to slightly reduce the size of the device, it turned out 2x frequency (the place for the capacitors on the board 18 - 8 (or what we want), the board under the gainta g1910, now on / off, tone and frequency - "buttons", the choice of frequencies is implemented via relays (like on 5 mask), the indication of operating modes is introduced, the microcircuit 4041 has been removed, capacitors have a choice of ceramics or film ...

Wow. That's really small and neat enclosure.

Looks really good.

Wait to here how it preforms.

[Toros]

best BUY adg444 15v 70 om resistance work super good.
http://pdf.datasheetcatalog.com/data...897adg441_.pdf

If we are guided by your logic, the DG444 is an even better option because there is low on-resistance = 50 Ω

[Gwil]

Why is the 'on' resistance of the 4053 important? There's another 100k in series with each output, which is many times larger.

Also, I can see why a lower noise op amp would be better than an LM324 but its offset voltage doesn't seem to be very important (unless it's seriously unstable).

[vlambers]

Decided to slightly reduce the size of the device, it turned out 2x frequency (the place for the capacitors on the board 18 - 8 (or what we want), the board under the gainta g1910, now on / off, tone and frequency - "buttons", the choice of frequencies is implemented via relays (like on 5 mask), the indication of operating modes is introduced, the microcircuit 4041 has been removed, capacitors have a choice of ceramics or film ...

[pustareka]

All this is your assumption ... Draw and share a scheme that will work better.

read factory data.noassumption no fantazy no fake.factory sxeme work ok. trak signal highway. you see and mesure. no kill signal big resistance. need 15v no 5 or 3 or 1. test protobord work.

[Artyom]

Q1 is what ?

bad sxema ?

paralel 2 adg444 super senzitive good signal best depth and coins cash in hand. resistance 35 om. super good work 15v.

lm324 bad very bad ic u1c u1d dont put. need ICL7650 CHOPER IC x 2IC. Super ic work. Choper boot depth 30% garante.
ICL7650/53 are Improved Second Sources toICL7650B/53B♦ Lower Supply Current: 2mA♦ Low Offset Voltage: 1µV♦ No Offset Voltage Trimming Needed♦ High-Gain CMRR and PSRR: 120dB min♦ Lower Offset Drift with Time and Temperature♦ Extended Common-Mode Voltage Range♦ Low DC Input Bias Current: 10pA♦ Monolithic, Low-Power CMOS Design https://datasheets.maximintegrated.c...0-ICL7650B.pdf

magnum best work 15v power no no 5v. power 18v , stabilizer 15v. dekupled low broom. lm317.

All this is your assumption ... Draw and share a scheme that will work better.

[pustareka]

Q1 is what ?

bad sxema ?

paralel 2 adg444 super senzitive good signal best depth and coins cash in hand. resistance 35 om. super good work 15v.

lm324 bad very bad ic u1c u1d dont put. need ICL7650 CHOPER IC x 2IC. Super ic work. Choper boot depth 30% garante.
ICL7650/53 are Improved Second Sources toICL7650B/53B♦ Lower Supply Current: 2mA♦ Low Offset Voltage: 1µV♦ No Offset Voltage Trimming Needed♦ High-Gain CMRR and PSRR: 120dB min♦ Lower Offset Drift with Time and Temperature♦ Extended Common-Mode Voltage Range♦ Low DC Input Bias Current: 10pA♦ Monolithic, Low-Power CMOS Design https://datasheets.maximintegrated.c...0-ICL7650B.pdf

magnum best work 15v power no no 5v. power 18v , stabilizer 15v. dekupled low broom. lm317.