Fisher Gold Bug (original analog model) Brochure FRL870393-B

I will be retiring in the coming months and am preparing to get back into prospecting. My plan is to go "high tech".  My view is that I may want a VLF to search for small targets then switch to a PI to punch down deeper for any other potential targets over the same area.   I'm leaning strongly toward the Gold Bug 2 for my first detector. I understand after doing some research and watching a bunch of videos on YouTube that the GB2 really  excels at recovering small gold.
My question is,  considering it's operating frequency, what kind of depth is possible with the GB2 and considering ground mineralization?

Although we own Minelabs-Equinox, GP's & other detectors, more and more often my brother Jim and I are using the Gold Bug 2.  We've discovered that when we find a patch and after the small nuggets are found, tiny pieces still remain.  At the end stage, we can get even more pieces by raking the area.  Jim made me this collapsible rake, from a tiny collapsible four tine rake and a welded-on eight tine piece.  I can carry it in my backpack and it looks like just the tool for those tiny pieces.

Fisher Gold Bug Operating Manual, 307 KB pdf file, 32 pages
Fisher Gold Bug Data & Reviews
Fisher Gold Bug Color Brochure
First Texas (Fisher) Forum
This is the manual for the original 1987 19 kHz Gold Bug model. It was revised in 2001 and pictures of the Gold Bug 2 were used for the cover and layout pages, but the manual is for the older "black face plate" model.
 

I have a 1990s era Fisher Gold Bug, the original 19 kHz analog version, long since replaced by newer models. The old 19 kHz model was not particularly hot, but it did have an ability to ground balance out some hot rocks that newer and hotter VLF machines struggle with.
Original Fisher Gold Bug Data & Reviews
The detector came with a 10" elliptical search coil. I have a couple very rare 3.5" round coils that Fisher made for these models before the little 4" x 6" elliptical replaced it. It's the smallest search coil I've ever owned for a commercially sold metal detector, making the unit into more of a probe than a normal detector.
The threshold was cutting out if the detector was bumped, something loose, so it's been sitting idle for a very long time. I decided it was doing no good as is, and by chance had an opportunity to call Felix at Fisher recently. Felix is another old-timer in the industry like myself, who I have not talked to since I left my old dealership in Alaska over eight years ago. Anyway, since the detector is still actually functional Felix figured they could give it a good refurbish and fix whatever is loose.
The main thing I wanted, however, was to get the detector tuned for the 3.5" coil. Most people do not know it, but analog Gold Bugs are hand tuned for every coil. The coil they ship with is tuned for the detector, or should I say the detector is tuned for the coil. Accessory coils may or may not be a perfect match if the original coil is swapped out for something else. Long story short is I am asking them to match the detector to the 3.5" coil as well as is possible.
The original Gold Bug is a genuine classic. Prior to it, detectors were large square boxes with extremely poor ergonomics. The Bug features a very compact control box that is removeable from a S rod, enabling easy chest or hip mounting. The design seems normal now, but you have to have used what came before to see the genius of what Fisher did with the Gold Bug. 19 kHz was also a radically high frequency at the time, as people were just catching on to the idea that higher frequencies are better for small gold nuggets than the lower frequencies that were the norm of the time. The 19 kHz Gold Bug replaced the 4.5 kHz VLF-660 Mother Lode as Fishers top nugget detector. Frankly, Fisher was not seriously in the game prior to this point, with Garrett probably the leader in VLF gold detectors at the time. A new company named Minelab was just starting to sell detectors in Australia, and had yet to really make a name for themselves.
Anyway, control box and coil boxed up and on the way to El Paso. I'll let you all know how long it takes and what the result is.
Here is a picture of one of the coils. The Gold Bug coils first used a gray dual lead cable, which was replaced very early on with the stouter black cable used to this day. This is the older coil of the two, though it also has less wear. The one I sent in has the heavier cable but is in poor condition. I need to reinforce the coil ears when I get it back since one is cracking. But I decided I wanted to use the coil with the heavier cable, with this older one serving as backup until I sort this all out. And in case anyone is wondering, the old 19 kHz coils do not work on the newer digital versions of the 19 kHz Gold Bug.

3.5" round search coil for original analog Gold Bug
To reiterate what a radical design advance the Gold Bug was at the time, here is a picture of the detector it replaced, the 4.5 kHz Mother Lode...

Fisher VLF-660 Mother Lode metal detector
And the new 19 kHz Gold Bug...

Fisher Research originally released the 19 kHz Gold Bug model about 1987. It was a real breakthrough design at the time with a compact control box, S-rod, and elliptical coils. The detector is a good unit but is strictly all metal (no discrimination). It has no LCD readout and looks much like the current 71 kHz Gold Bug 2 but has a white lower rod and a black control panel face. Some people are confusing this old model with the new so be aware of this when looking at used detectors. The 19 kHz coils for the old Gold Bug will not work on newer versions of the Gold Bug below. The 71 kHz Gold Bug 2 is a totally different detector than the various 19 kHz models described below.
Around 2010 a number of new Gold Bug models were released by Fisher. First came the Gold Bug in 2009. Then came the Gold Bug SE (Special Edition) which added manual ground balance at a bargain introductory price. The SE with minor tweaks later became the Gold Bug Pro at a higher price. So now we have two basic versions, the Gold Bug and the Gold Bug Pro. They differ from the old 1987 model by having an LCD readout. The standard version of either detector comes with a 5" round coil. There is a Gold Bug DP (Deep Penetrating) which is nothing more than a Gold Bug Pro with an 11" x 7" DD elliptical coil instead of a 5" round DD coil.
The only difference listed by Fisher between the Gold Bug and the Gold Bug Pro is that the Gold Bug Pro has a manual adjustment option for the ground balance and also offers "higher sensitivity".
Both models use a "Ground Grab" button as a simple ground balance method that is quite effective. The Gold Bug Pro allows you to also manually adjust the ground balance setting up or down. The manual adjustment can be used in conjunction with or separately from the Ground Grab button.
The big question is the "higher sensitivity" claim. There are two possibilities here. First, that the Gold Bug Pro actually allows for higher gain or sensitivity levels. However, I was in marketing too long and have a more jaded thought. Manual ground balance allows for a higher degree of control that if used properly can get you more sensitivity. There is a very distinct possibility the higher sensitivity claim follows directly from the ability to manually ground balance the Gold Bug Pro. This could be tested with both units set side by side with identical ground balance settings and max gain. If the Gold Bug Pro is inherently more sensitive an air test should show it. I have not had the chance to do this my self but if somebody wants to there you go.
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My opinion? I believe the Gold Bug and the Gold Bug Pro if outfitted with the same coil are basically the same detector. The only real difference is the manual ground balance option on the Gold Bug Pro. Do you need it? Not really, and especially when you consider that for $499 vs $649 that is probably all you are getting. The Ground Grab function is remarkably effective and would suit most people just fine.
I personally do like manual ground balance and so for me spending the extra money to get it is a non-issue. I do as a rule tell people that if cost is not an issue get the Gold Bug Pro. It is far more popular and would be easier to resell. But in all honesty I think the Basic Gold Bug is the real bang-for-the-buck unit. There is nothing else close to it at the $499 price point that offers full LCD readout target discrimination while in full power all metal prospect mode.
I should note that First Texas owns both Fisher and Teknetics. The Fisher Gold Bug DP (Gold Bug Pro with 11" coil) is marketed by Teknetics as the G2. The Fisher Gold Bug DP goes for $699 and the Teknetics G2 is $749. The $50 extra gets you a pistol grip rod instead of the Gold Bug S-rod and an arm strap. Nice gray paint scheme also. Really boils down to pistol grip vs S-rod, purely a personal preference thing.
I use the 5" x 10" elliptical myself and consider it to be the best all around coil for the Gold Bug. However, right now you have to get it as an accessory or as part of a two coil package. Fisher would be doing us a service to release the Gold Bug with this coil as standard on the unit.
My Gold Bug 2 is slightly better on the tiniest of gold but the Gold Bug Pro easily outperforms the Gold Bug 2 on larger nuggets at depth. For all around nugget detecting the Gold Bug or Gold Bug Pro (and G2) have a better balance of both small gold and large gold capability than the Gold Bug 2.
Fisher Gold Bug Pro & Teknetics G2 Detailed Comparison
To recap first came the original 1987 era Gold Bug with knobs and switches:

1987 era analog Fisher Gold Bug
Then in 2009 we got the new Gold Bug:

Fisher digital Gold Bug
Followed quickly and briefly by the Gold Bug SE. Note how the plus and minus buttons now have dual functions, both Disc and Ground Balance, compared to the basic Gold Bug above:

Fisher Gold Bug SE
The Gold Bug SE was basically the prototype for the Gold Bug Pro, which got a new faceplate decal and a higher price:

Fisher Gold Bug Pro
And finally, the Gold Bug Pro was also marketed under the Teknetics line as the G2 with a different rod/handle assembly:

Teknetics G2
Gold Bug Pro DP compared to Teknetics G2:


Click on images below for larger versions.....