Messages

241

Technical / Re: DC Offset in operational amplifiers in DC coupled front ends of P.I detectors

« on: June 01, 2014, 11:09:41 pm »

Hi Barry, the AD797 is a much better chip compared to 5534  as it has a lower noise floor at low frequencies, there are even better chips around that make the 10hz corner frequency noise of an AD797 look bad.

242

General Discussion / Re: Battery for a GP series detector

« on: February 25, 2014, 01:58:45 pm »

Hi Wes, It is not a good idea as a fully charged GPX is 8.4 and safety cut out on a GP is around 7.8-8 volts.

It can pop the input soft start Fet and it takes out some of the circuit tracks as well.

243

New Detector accessories / We are now doing major upgrades to the F1A4 Minelab detectors.

« on: February 13, 2014, 10:44:13 pm »

Watch this space, no one else can upgrade the F1A4 detectors to our new specifications... These are great for finding Quartz Reef Gold.

244

New Detector accessories / New set of upgrades now for SD2000 SD2100 F1A4 series detectors

« on: February 13, 2014, 10:41:22 pm »

We have been busy. Have a series of 7 new upgrades coming out that will make these old detectors some of the deepest detectors available if not the deepest for large Gold and Treasure.

245

New Detector accessories / Re: SD GP GPX Boosters now available Class D perfect audio

« on: February 13, 2014, 10:39:03 pm »

Hi Red,  We can make a battery tester with cable connect for the SD GP GPX... Just redoing all the adds.

246

New Detector accessories / Re: SD GP GPX Boosters now available Class D perfect audio

« on: January 22, 2014, 01:36:30 pm »

Hi Red, We are sending most of these to our customers over in Africa, I have some more performance enhancing items under way...Its flat out R&D here.

247

New Detector accessories / SD GP GPX Boosters now available Class D perfect audio

« on: January 20, 2014, 01:22:32 am »

http://detectormods.com/booster

248

General Discussion / Re: carbon coils

« on: January 09, 2014, 11:54:26 pm »

Hi Red, Im not sure if Chris is making coils for the ATX, good timing, i was just cleaning out the spammers..

249

Technical / DC Offset in operational amplifiers in DC coupled front ends of P.I detectors

« on: January 04, 2014, 02:58:13 pm »

After testing the input stages on various detector I have found that many of the AD797 opamps with a spec sheet indication of 25mv DC offset is not the case when measured in some detectors.
Offset voltages in excess of 100mv are quite common.  Adding a potentiometer and trimming the Offset after 15 minutes run time to DC makes for a much more stable and quieter detector. As the first stages are DC coupled, reducing the Offset voltage makes for a much more behaved quieter detector. Frequency compensation can also be carried out to reduce Radio Frequency interference without degrading the low frequency slew rate or settling time of the opamp. 

250

Technical / Hot Weather Cold Weather Dry ground Wet Ground Daytime Nightime.

« on: December 30, 2013, 07:20:37 pm »

Hot weather = Less Nuggets detected.
Cold Weather = More Nuggets detected.
Wet Ground = Less Nuggets detected.
Dry Ground = More Nuggets detected.
Night Time  = More Nuggets detected
Day Time   = Less Nuggets detected.

Why?   Who knows the answers?

251

General Discussion / Re: New Mods being worked on.

« on: December 30, 2013, 07:13:53 pm »

I think Shep has the early mods, why go and buy a very expensive new detector when the older ones can be made to go deeper and run more stable.....Soon I will putting out another lot of new mods that will blow everyone away... Just got to keep it under wraps at the moment.. Already I have had numerous hack attempts from France, USA and China... All designs now are on non net connected computers, even paper and pen on the crucial design aspects..

252

General Discussion / Re: The Ultimate detector project

« on: December 15, 2013, 04:35:56 pm »

Hi Red, these projects take longer than anticipated, but when it's ready you'll be the first to know.

253

New Detector accessories / Re: New add on for any Minelab with a massive improvement in performance.

« on: November 22, 2013, 08:46:38 pm »

Hi Red, yes it it will but the most benefit will be for the GP Extreme onwards.

254

New Detector accessories / Re: New add on for any Minelab with a massive improvement in performance.

« on: November 21, 2013, 11:19:06 pm »

Not sure yet,  Just got to do the finishing touches.. 

255

General Discussion / Re: Gold Gem and Treasure magazine

« on: November 20, 2013, 07:57:03 pm »

They are printing plenty of my articles,   even better ones to come.