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I've been discussing qualities of Minelab lately (mostly in a negative light) and I decided to step back and ask myself why I use their Equinox 800 almost exclusively.  It's worth starting out by saying I'm an old coin hunter (where 'old' is meant to refer to 'coin', although it also applies to 'hunter' 😁) the majority of the time, and and native gold hunter when the opportunity presents itself (not often enough).  I've never detected near salt water and only occasionally (in shallow creeks) detected in water.  Relics and jewerly aren't ignored but they typically only show up when I'm coin hunting, as peripheral bonuses.

I want to emphasize from the beginning that I'm not reviewing/comparing these two for all conditions or even conditions that might apply to the average detectorist.  This is all about me, well, about my conditions, particularly my hunting preferences/goals.  Although that may seem selfish/uninteresting/unapplicable to readers here, in the least it might get you thinking about how different detectors 'weigh in' for your type of detecting.  A Minelab GPX 5000 might be well worth the cost and backbreaking swings for someone, but if it doesn't fit your intended targets and locations then you wasted a couple thousand $ and may not even be maximizing your intended finds.

I'll put some more caveats at the end, but basically I've broken this into three parts.  The first are some quantitative/qualitative properties that are easily measured/stated.  Next are the less quantifiable features/performances that mean the most to me.  3rd I list qualities that I determine are important but for which I don't see a significant advantage for either model based upon my usage.  And finally I'll mention some of the things which most comparisons emphasize but for which I don't because..., well, you can read the reasons I give then.

For completeness, the Fisher F75 is a 13 kHz single frequency IB/VLF detector whose initial model was released 11-12 years ago.  Although I own the F75 limited (Black), I'm instead comparing the F75 plus since it has all the features I use at a lower price.  The Minelab Equinox, both a simultaneous multifrequency and selectable multifrquency (5 kHz to 40 kHz) was released early 2018 with two models which continue to be the only ones available.  The 800 model has more features.  That is the one I own and compare here.  One final clarification:  in the second section, '++' means a feature/performance which is very important to me, and '+' means important, but less so.  I emphasize 'to me'.  That is, it might be a small or meaningless difference to many but it matters a lot to me.

756022263_Screenshotat2020-07-03145224.png.2f6f4093086b94ee8d52291ef004cec4.png

I suspect many of you have noticed I haven't included such fundamental features as waterproof/submersible and multifrequency/single frequency.   The former is because it doesn't affect my hunting requirements.  The latter is a bit more complicated.  Rather than mentioning operating frequencies, I chose to emphasize the performance features.  I don't really care what frequency/frequencies are being used as long as the detector performs (or outperforms) in the categories that matter to me.  For example, simultaneous multifrequency improves the accuracy of the TID for deep/weak targets.  The Eqx 800 got a ++ there.

It should be clear that in the center section, which IMO is the most important, the Eqx 800 clearly outperformed the F75.  My preference for the Eqx 800 as my primary and the F75 as my backup is thus justified.

Update 1:  based upon some questions that follow in this thread, I will do more detailed depth test comparisons to clarify my claim that F75 has more raw depth.  I'll report those results in this thread as soon as I finish and will put another update on this post to call attention to it.

Update 2:  I've done a detailed hybrid (in-ground + air above ground) depth test in my test garden and those results can be found later in this thread.  As such I've removed the 'raw depth' line in the above table since it's been superceded in much greater detail in the later post.  If interested you should read that.

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Great write up Chuck!

I would still consider myself a F75 fan. The raw depth thing I am betting is a reference to the excellent true threshold based all metal mode, something the Equinox lacks.

I have owned a lot of “Dave Johnson” detectors over the years. Dave went from designing the Diablo UMax and Tesoro Lobo ST for Tesoro, and then on to the GMT and MXT for White’s.

If you owned Dave’s detectors over the years you can note the progression in his specialization if VLF gold nugget detectors and related mid-frequency designs. Dave went from the 14 kHz MXT for White’s to designing the 13 kHz T2/F75 platform for First Texas.

The F75 in my mind is very much the MXT 2 in many ways. I was a big MXT fan and was very excited when Dave came up with the T2/F75 platform. The F75 in particular featured ergonomics that in my mind are second to none. Just reading weights on a chart does not do it justice. Balance matters, and anyone swinging an Equinox and then an F75 can attest to that. Absolutely no comparison in the ergonomics department, clear win for the F75 as less fatiguing than the lighter but nose heavy Equinox.

For me the Achilles Heel of the F75 is the inability to adjust the ferrous/non-ferrous tone break in any mode except monotone. After much back and forth I ended up with Dave’s simpler Gold Bug Pro/G2 platform almost entirely for the ability to adjust the tone break setting in two tone mode. In any F75 tone mode except mono the tone break is set at 15, where in reality gold can commonly read as low as 6 on the F75, meaning in any multi tone mode with the F75 weak gold targets can read ferrous way more than they should. The only fix is all metal and watch the numbers, or mono tone mode and set the disc where you want to blank rejected targets.

All that said, I really liked the F75 and made a lot of great finds with it. Every time Fisher drops the price I look again. But I have to remind myself that it is very likely to sit unused while I grab my Equinox yet again. I’ve never found nostalgia players to really ever work out for me. There was a reason I moved on in the first place, and it no ever seems to change if I go back and revisit old models I used to favor.

herschbach-fisher-f75.jpg

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1 hour ago, Dances With Doves said:

In your ground Steve would a f75 go deeper in true all   metal vs . Nox in the multi gold modes on a nickel in your opinion?

I don’t know, as I do not have both on hand to say for sure. It would likely be close, but here is the catch. On the F75 it would be a faint all metal signal with no target id. Raw depth I read as meaning no discrimination... just a signal.

Chuck has both and a U.S. nickel - test time! :smile:

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19 hours ago, Dances With Doves said:

Raw  depth in what kind  of ground? mild.

 

16 hours ago, phrunt said:

Where are you noticing a depth improvement with the F75 Chuck...?

Steve got it right -- I was referring to the F75's motion "all-metal" (minimally filtered) mode -- a feature the Equinox doesn't have.  This is based upon my test station investigation of a coin (now I forget -- should dredge it up -- but think it was a silver dime).  In my test setup the ground reads 3 bars on both the F75 and the Fisher Gold Bug Pro.  I don't know how the two detectors compare in other (milder or stronger) mineralization.

While we're discussing this particular aspect, two other things come up.  The F75 also has a non-motion all metal which I think is the same circuit used in pinpoint mode.  That is even deeper than motion all-metal, but the signal drifts with time which is why motion all-metal became the standard many years ago.  Also, the F75 has what is called "mixed mode" meaning it can run in all-metal and discriminate modes simultaneously.  However, that doesn't allow you to squeek out more depth on the discriminate side.  As such, not only do you lose digital TID readout for weak/faint signals (just blanks out or shows '--') but also the digital TID becomes unreliable even when the all-metal mode is still going strong.  Again, all that is in my 3 bar mineralized ground.

18 hours ago, Steve Herschbach said:

The F75 in particular featured ergonomics that in my mind are second to none. Just reading weights on a chart does not do it justice. Balance matters, and anyone swinging an Equinox and then an F75 can attest to that. Absolutely no comparison in the ergonomics department, clear win for the F75 as less fatiguing than the lighter but nose heavy Equinox.

I gave the two detectors equal/neutral score for balance.  I do agree that ergonomics-wise (balance, but also other features such as the adjustability of the side lobes of the armrest -- something I'm not aware of in any other detector other than its sister Tek T2) that I've never swung a detector like the F75.  Early this year I had problems with my left wrist (I swing the detector with my left arm) and modded the Eqx with the ML X-Terra S-shaft and added 0.25 lb counterweight.  I did write all that up here and was thankful to shaft maker Steveg for his advice and explanations.  Anyway, since doing that my wrist (which suffers from osteo-arthritis, as I since realized) has improved a lot.  I doubt that is due to my shaft mods alone (how would I know) but, interestingly I never notice arm or back fatigue anymore on my typical 3-4 hour hunts.  Used to be (with all my detectors, if I recall) I had back pain for the next 12-24 hours.  Again, it could be a coincidence unrelated to my shaft change but I'm not turning back the mod.  😁  As a result I decided to give the 'balance' category a neutral score.

 

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10 hours ago, phrunt said:

You're not sneaking on a Detech Ultimate to compare are you 🙂

Come on..., well..., oh..., oops.  😅

9 hours ago, Steve Herschbach said:

Chuck has both and a U.S. nickel - test time! 

Tell you what, I'll put the 12"x15" on the Eqx and the Detech Ultimate 13" (round) on the F75 and do some tests in the next couple of days.  I have a 5" deep 'copper' Memorial penny and a 6" deep 'nickel' 5 cent piece.  I've developed some shims which allow me to accurately & measureably raise the coil off the ground until I reach the depth limit.  (My shotgun test stand has some nearby iron bits which need to be removed before I can do extreme depth tests where you're listening for faint signals.)

Given the coil equivalency formula I've developed (square root of width times height), trying to compare stock coils (11" round for Eqx and 7"x11" eliptical for F75) doesn't give a very good match.  However, square root of 12x15 = 13.4; that's pretty close.  Stay tuned.

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Got out to my test garden finally (weather is bad and I'm sensitive/allergic to chiggers but finally toughed it out -- I may pay for that in a couple days).  I'm going to give an intro and if you're not going to read it (and heed it) then you probably shouldn't read the rest, either.

Introduction to and Fundamentals of Metal Detector Depth Measurements

One of the most often asked questions about detectors, new and old, is "how deep will it detect?"  That's an easy question, too easy.  The only appropriate answer is "that depends...".  Let's take a look at what this depends upon, in not necessarily the order of importance:

1) Target goal -- coins, large jewelry, small jewelry, gold, platinum, or silver jewelry, natural gold nuggets (and what size), non-ferrous relics, ferrous relics, large caches, small caches...?  (I'm sure you can think of more.)

2) Natural ground conditions -- wet, dry, how mineralized (i.e. Fe3O4 content), salt content, ground phase, surface rubble, hot rocks, cold stones?

3) Site conditions -- ferrous & iron trash, aluminum trash, lead shot and/or bullets and fishing sinkers, gun casings?

4) Electromagnetic Interference (EMI) -- too many to mention; you've just got to figure out a way to work around it by adjusting your detector, etc.

5) Detector options -- what coil(s) do you have or plan to use?

6) How do you determine if a target signals or not?

Other factors also exist, such as the skill and (very important) objectivity of the detectorist doing the test.  These are impossible to quantify but should not be ignored.

Now that we've defined parameters, let's get on to the test I actually performed.  Obviously I didn't cover all possible situations!

Conditions of this test

1) Target -- (two different) -- 5 inch deep USA Memorial Cent (95% Copper, 5% Zinc) and 6 inch deep USA Jefferson 5 cent piece (25% Nickel, 75% Copper).

2) Natural ground conditions -- pretty dry (but not like late summer desert).  We've only had about an inch of rain in the past 4 weeks.  Fe3O4 reading of 2 to 3 bars on both the Fisher F75 and Fisher Gold Bug Pro.  This could roughly be characterized as 'moderate mineralization'.  Grass covered smooth ground with no rocks that my detectors are sensitive to, and no known salt content.

3) Site conditions -- Around these two buried targets I've removed all background metal that any of my detectors are sensitive to.

4) EMI -- now we're getting to the painful part.  Residential neighborhood and close to my house, so I have to deal with various sources of EMI.  I'll discuss more below when I talk about the settings I used.

5) Detector options -- Since I'm doing a comparison test I chose coils which are roughly equivalent -- for the F75 I used the Detech Ultimate 13 inch round; for the Equinox 800 I used the Minelab 12" x 15" (largest of the three available coils).  As mentioned, using square root of height X width for an eliptical, that gives 13.4" as the equivalent round coil in the case of the Equinox elliptical.  I consider that close enough, and the best I think I can do finding coils that match these two detectors.

6) How do you determine if a target signals or not?  This has to be subjective.  I used a threshold technique in all cases, listening for a clear signal above threshold (similar to how native gold detectorists typically hunt).  In most cases I could squeeze out another half inch, maybe hearing a warble, but when that happened I backed off that half inch and confirmed I was getting a clear signal -- then recorded the clear signal depth.  For the Equinox I had the added feature that I could look at the digital target ID and see if I was getting something close to expected there, although in the end my ears were just as good of an indicator, and maybe more objective.

My depth resolution was 1/2 inch, meaning that was the smallest increment I used.  That's also my estimate of the measurement uncertainty.  My method was to stack up wood 'shims' next to the target (not covering the target sweetspot, if that even matters) -- slightly off to the side.  Thus the coil rode the top of the shim pile.  Note that each coin was only a certain depth in the ground (5" for the 1 cent, 6" for the 5 cent) and thus this is a kind of hybrid ground+air test.  The values below are the total target-to-coil distance, so the sum of depth in ground plus coil height above ground = shim stack height.

Detector Setups (modes & settings).

Fisher F75 Ltd ("black") Motion All Metal mode, Ground Balanced, Gain = 99 (max), threshold just above silent (a bit wobbly), internal speaker.  (This was the only mode and settings used.  I'll comment later on why.)

Minelab Equinox 800 -- 3 setups (all ground balanced separately):

a) Field 2, multi-frequency, recovery speed = 5, iron bias FE=0, no discrcrimination (all 50 channels open), 2 tones, gain = 22 (highest I could operate and not be swamped by EMI).

b) Gold 2, 20 kHz single frequency, recovery speed = 5, gain = 25 (max).  (Note:  EMI was terrible in multi-frequency, even with lower gain.)

c) Gold 2, 40 kHz single frequency, other settings same as b) above.

Results.

For the 5" depth-in-ground 1 cent (high conductor) the F75 picked it up 1/2" deeper than the 800's a) and b) settings above (I didn't measure for c) settings).  That is, total target --> coil distance 11 inches for the F75 and 10.5 inches for the Equinox.  So slight edge to F75, but right at the (estimated) uncertainty limit.

For the 6" depth-in-ground 5 cent (low conductor) the order of performance (worst to best were as follows):

Eqx setting a)            -- 11 inch total target --> coil distance.

F75 & Eqx setting b) -- 13.5 inch total ------------------- these two tied in depth.

Eqx setting c)            -- 15.5 inch total -------------------- clear winner for these conditions!

Summary, Conclusions, and final comments.

I emphasize that these kinds of tests depend strongly upon conditions.  I've tried my best to define what conditions and settings I was dealing with / using.  In particular I had to conform to the EMI environment present.  The F75 was slightly better (but at the limit of uncertainty) for the high conductor.  Half an inch, at least in my book, isn't much and other factors (e.g. target ID accuracy) could easily outweigh this small increment.  But the F75 did outperform, slightly.  For the low conductor, the Eqx 800 in Gold 2 mode and operating at 40 kHz was the clear depth winner by 2 inches.  The most surprising thing to me is that Gold 2, 40 kHz clobbered Field 2 Multi by 4 inches!

Previous testing has shown that the discriminate processes of the F75 are noticeably inferior depthwise for my test garden.  I did try the F75 in non-motion all-metal, a mode that today is almost unheard of (but it was standard back in the late 1970's), although many detectors use this mode for their pinpoint function.  In some air tests I've done with large objects (Weber Kettle charcoal grill :biggrin: where you measure not in inches but in feet!) this mode is super sensitive but because of its instability with time and other quirks it's not a commonly used mode and I was unable to get it to stabilize (it may have been picking up on nearby iron trash in the ground which the other modes and detectors were insensitive to).

The Equinox in particular has hundreds to even into the thousands of setting combinations.  I chose the ones I thought were both most appropriate and also most sensitive to the targets, within the EMI limits of my site.  I'm not interested in investigating further unless there is a big gap (oversight) in my tests.  One final point about the Equinox vs. F75:  as pointed out in the initial post in this thread the F75-plus model sells for $650, which turns out to be the same price as the Equinox 600 (and $250 less than the Eqx 800).  But the 600 model doesn't have a gold mode, so it looks like if you lock the dollar cost to being equal (ignoring the cost difference when buying larger coils for both F75 and Eqx 600 where the Ultimate coil in USA is about $50 cheaper than the ML 12"x15"), the F75 has a bit of a depth edge in my test garden, and particularly my EMI environment.  Of course depth isn't everything, to most of us anyway.  And as always YMMV!

 

 

 

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Great test and I learned some things. I actually thought the F75 would show up a little better than it did in all metal mode. The good news is you have confirmed that my having an Equinox and having parted ways with the F75 is even better than I thought. Very interesting the difference in Field 2 and Gold Mode 40 kHz in particular. Looks like I need to do some more investigation myself. Thanks for going to all that effort!

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4 hours ago, phrunt said:

That Detech Ultimate is a killer coil though... still up there as one of my favorite VLF coils,  better than it's main competitor for size the Nel Tornado which I also have.

It's amazingly lightweight for its size.  It's the only Detech coil I own so I don't know if their other coils are lightweight as well.  This is how every open coil should be.  Interesting that White's collaborated with Detech, for the MXSport and MX7 coils, possibly others(?).  They did some things right (IMO).

 

4 hours ago, phrunt said:

I wish it was made for the Equinox.

I suspect Detech would be thrilled to do that....   (Been down this dead end path before, haven't we?  I'd settle for a 5"x10" closed coil.  Doubt we get that, either.  Come on, Nokta/Makro!)

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