Reg Mods Update

[CaliGold]

On 9/3/2023 at 5:52 PM, Jim in Idaho said:

Thanks, Pat, but don't confuse my tiny bit of knowledge with Karl's far great ability. Compared to him, I'm a hack with a small bit of experience with one particular detector. We're very fortunate to have him to explain all this to us, and I, for one, am grateful.

Jim

Karl is the man no doubt and you guys went to great length to share your mods so I thank you again. I did the c42 jumper/on/off switch mod tonight. Taxed my skills a bit but it works. With the switch on and the gain boosted the machines emi went up a bit and I had to be careful what direction I held it in in my garage as the sadie coil was picking up anything in the structure. I put it in low conductor and GB off and it  tamed down a bit. I WAS able to run GB on later in testing but I put it back in low conductive mode to avoid the coil sensing everything "big" in the garage.   I was able to get it to stabilize for some hand held air testing of my sample gold nugget targets. The side of coil sensitivity went up on all sizes as did depth. At least 25-30% it seemed.  Great mod so far! I may switch the R9 and R14 2512 sized resistors out for 3 watt (have 2 watt installed now, originals were 1 watt) as the battery was a little "warm" when I removed it after about 10 minutes of testing the gain switch. I'll do backyard quartz pile testing tomorrow maybe even hit river and bury some gold. 

[CaliGold]

Here is switch installed. Tight space there.  A little close to the caps lower down on board inside but cleared ok with no contact.  Debating on doing the swing speed mod when caps arrive this week. @Melano87 mentioned losing depth on this mod? 

 

 @Geotech or @Jim in Idaho  Did you guys notice any depth changes/losses on sweep speed mod? Thanks!

[Jim in Idaho]

I had no negative effects from doing the SS mod. Looks like you did a good job on the switch. Wish I had time to do that mod on mine. With the dry sluice project, and the resistivity, I'm buried in projects...LOL. Having a LOT of fun with the resistivity, though it's fairly boring setting up and collecting all the data. Best of luck on the gold, Pat. Looking forward to tests and results.

Jim

 

[Melano87]

3 hours ago, CaliGold said:

Here is switch installed. Tight space there.  A little close to the caps lower down on board inside but cleared ok with no contact.  Debating on doing the swing speed mod when caps arrive this week. @Melano87 mentioned losing depth on this mod? 

 

 @Geotech or @Jim in Idaho  Did you guys notice any depth changes/losses on sweep speed mod? Thanks!

Great job !

 

For losing depth :

 

[CaliGold]

On 9/5/2023 at 12:56 AM, Melano87 said:

Great job !

 

For losing depth :

 

Thanks for the thread link. Interesting. So upon testing the new c42 jumper switch I installed, I found the increase on signals to be pretty intense. It makes the machine run a little hot but maybe that was just the sun and the 16v battery I was using. The gravel in the river bed I test in is pretty intensely mineralized. I guess thats why the wine around here is so good. 😉    Noise goes up a bit with switch on but I slowly learned how to harness the extra gain. It's a nice option to have and I imagine it will be especially nice on bedrock with more continuous surface ground signal coming in to base GB off of. I'm glad I did it. It allowed me to run my AA battery pack that I brought which sat at around 11.5 volts and then kick on the Gain Switch and punch deeper on tests. I didnt do measurements on all targets but lets just say IT WORKS and I hope anyone using this mod is well versed in tuning GB, Frequency, and Pulse Delay with test targets at the actual site of detection or prospecting. Very powerful in the right hands. ... I also tested my water proofed sadie coil (sika flex 221) and all was well there... Good signal above waterline to 6" deep to that 1.1gram nugget in the ziploc bag and no issues underwater. So Far So GOOD.

[CaliGold]

 

@Geotech anyone here know about removing R86 resistor down by the gain control area? Saw online... Is that flying too close to the sun? Thanks! p.s. thanks again on the schematic etc. Switch on c42 went well... works good.

 

-Pat

[Geotech]

R86 slightly limits the max gain. Removing it increases the max gain by 10%.

[CaliGold]

On 9/7/2023 at 9:12 AM, Geotech said:

R86 slightly limits the max gain. Removing it increases the max gain by 10%.

Thanks Karl!

 

@Jim in Idaho what do yo think of this idea Jim? Karl is the guru obviously but has anyone got any anecdotal info on this? @Melano87 know anyone who did that-  removed R86?

 

Very tempted to remove R86 and still on fence with swing speed mod. I waived a .15gram (about just shy of 2 grains) test gold flake in front of sadie coil fast today and it got good decent signal at 2 inches so maybe unnecessary? 

 

Does gain increase depth or is that only possible by current from battery etc? (man I want to use that 20v battery again) Terrified though... Maybe if I swap out R9 and R14 current 2 watt resistors for 3 watt (I just got some) The Q4 installed with heat sink is already a higher rated voltage model with some different specs here and there that as a lamen  I read to be an "upgrade". 

 

Looking forward to the days when my posts on here are the "look at all this Gold I found with my modded out SL" sort...

 

Many thanks, gentlemen. 

 

 

 

 

[Jim in Idaho]

IMHO, a person should move with caution on any mod not suggested by either Reg Sniff, or Karl. I doubt a 10% increase in gain would be noticeable in the field. Some mods are all about the risk/reward ratio. Same goes for boosting the voltage...at some point you're risking the health of your machine for very little increase in depth/sensitivity. Boots on the ground, and geologic self-training on where to detect would make a bigger difference.

Jim

[Melano87]

I had seen this modification several years ago with R86 on a French forum.

I know that some French people had made this modification successfully but had not made (had no knowledge) of the C42 modification  at the time.

I am tempted like you to remove this resistance.

For the voltage, my previous tests with a TDI plate (not SL) that ended in failure no longer push me to go higher in voltage than my 4x18650 (about 16.7V).