Jump to content
Steve Herschbach

Fisher Impulse AQ (formerly Aqua Manta) Pulse Induction Metal Detector

Recommended Posts

The Aqua Manta has finally arrived in the form of the new Fisher Impulse AQ. The Manta has been officially named the Fisher Impulse AQ, a development that happened later in this very thread. It has also been revealed a gold prospecting model is under development. Go to the link above for the latest information and photos. Or quick jump to the Fisher Impulse AQ Specifications & Data & Fisher Impulse AU Specifications & Data pages. The information below remains for historical purposes.


The challenge I have for Fisher or anyone else is to make a dry land ground balancing PI that weighs under 4 lbs yet is more powerful than a TDI SL. The alternative is waterproof but under 5 lbs. The price must be under US$2000.00 Waterproof Pulse Induction Metal Detectors Compared

The Fisher Aqua Manta (edit 3/2019 now known as Impulse AQ) has been rumored for some time, and confirmed by First Texas as a project nearing completion. Prior threads:

January 2015 New Fisher Pulse Induction

January 2018 New First Texas PI Under Development

June 2018 Aqua Manta Pulse Induction Beach Detector

The long story short is this is a project by Alexandre Tartar. The Manta is most likely an offshoot and improvement on the orginal Eric Foster Goldscan circuit. Alexandre has built at least three major prototype devices before the rights were acquired by First Texas. The following photos and information is derived from this thread where the V3 prototype is sold.

Here are the basic specs as described in advertisement (the seller is French and translating):

"I sell a "prototype" Manta v3

There are only three copies of this detector and it is the best of three ....
(See mantametaldetectors website)

Pulse induction, works exclusively with mono coils to the beach, possibly for the land, but no ground control

Calibrated for low conductors, gold and platinum, among other. Delay 7us of 17 volts more sensitive, deeper and faster than Deepstar

Equipped with a coil, Manta, latest generation
she has one month, the quietest and most efficient on the market, all brands included. (it will operate on TDI and Deepstar)

Connector Type TDI, it accepts all coils (mono) of TDI / GPX

Weight: 1.5 kg without battery that is worn at the belt
headphone jack and on / off switch on the battery pack (lipo) supplied charger
more than six hours of detection at full power.

Carbon Rod Anderson + extra cane down
braided nylon belt military style

All the possible settings and need a good PI
SAT speed, TX frequency, noise threshold, delay, volume, sensitivity....

The delay was 7us , lets see gold ends
very thin rings, earrings, jewelry hollow that other detectors can not see
and of course, the wholesale jewelry it goes deeper

Ferrous recognition by a double beep well marked"

What I find interesting is this note "Pulse induction, works exclusively with mono coils to the beach, possibly for the land, but no ground control"

Yet here is the picture that accompanies the advertisement. Now remember this is from March 2016, almost three years ago. The prototype clearly has labels for ground controls...

Alexandre Tartar Manta V3.0 prototype

The control markings as seen above:

  1. Volume
  2. Threshold
  3. Sensitivity
  4. Sat Speed. Motion. (recovery speed)
  5. Tx Frequency (transmit frequency, usually to offset for EMI mitigation)
  6. Pulse Delay. GB Type (the shorter the pulse delay, the more sensitive to tiny metal and salt water)
  7. Ground Balance (usually a ground balance control, but ad says this is lacking?)

Statements by First Texas suggest version 1 of the new machine is aimed at beach use and may not be suitable for land use (gold prospecting). That in turn makes me think work on the ground balance system is lagging and may be key to the future of the machine. Will it be beach only, or have a future for gold prospecting?

I have to assume the unit will be competitive when it comes to the horsepower, or why bother? Until now the Eric Foster Deepstar is generally acknowledged as one of the deepest beach PI detector’s ever made. And the ad says “more sensitive, deeper and faster than Deepstar”. That being the case what really has my interest is the weight and compactness being displayed. The following photo collage from the advertisement shows the size of the control box and belt mounted battery:

Alexandre Tartar Manta V3.0 prototype

Granted the battery is belt mounted, but that is one tiny control box. I have to think that First Texas can slim down the circuit board and use a top notch integrated rechargeable battery and get this machine into a very compact package - hopefully waterproof and with wireless headphone capability built in.

Well, that's about all I know about this one. This thread will collect any new information as it is available. This is one of a couple detectors I am watching so fingers crossed for a 2019 release. It is encouraging that Alexandre's original website at http://www.mantametaldetectors.com/ has been taken over by First Texas and is displaying this banner:

Fisher Research Labs - New Pulse Induction metal detector COMING SOON!

  • Like 8
  • Thanks 1

Share this post

Link to post
Share on other sites

 I already want to see that machine and how it will unfold on a daily basis

  • Like 1

Share this post

Link to post
Share on other sites

Sounds like a great machine.  Good for gold prospecting, maybe.  Beach hunting, yes.  But I don't get to beach hunt but once a year.  Waterproof, great.

But I'm still waiting for the day when a PI will be developed that can discriminate out nails and still see the deep silver.  Not trying to manipulate the ground balance settings achieve such a feat. 


Share this post

Link to post
Share on other sites

The poster who goes by “LE.JAG” is the chief field and development tester for the Manta project.  His name is Denis - don’t know his last name.  As as far as I can determine, Alexandre Tartar has only posted on the Geotech forum and then under the “handles” of “Poseidon”and “Asgard.”

It was a post of his on Geotech which got Carl Moreland interested in his work and after some back and forth resulted in First Texas doing an “aquihire” of the Manta project and the team.

The salt water beach detector market is a niche within a niche - water detecting - salt not fresh - beach and wading vs. diving. Fresh water, lots of waterproof detectors will do fine - even not so waterproof ones if you are careful.  Salt water is another problem.  Diving is yet another problem, pressure resistance greater and in the case of a PI detector, rules out the use of very short minimum pulse delays due to the huge volume of water.

Gold at the salt beach - that’s the manta’s meat. Their belief is that it will be the best detector for that that has ever been fielded.  It has to appear however before any of us can see if they are right!

As far as land use, it does have ground balance control.  It is labeled in the prototype “accept” and “reject”.  I expect this indicates that the iron IB/Silence feature is at least partly controlled by changes in the GB settings. 

The fact that they have announced the development of a land version probably means that the GB function for the beach machine “AquaManta” is utilized in a way that makes it not optimum for cancelling highly mineralized inland ground.


  • Like 6

Share this post

Link to post
Share on other sites

Leave it to Carl, to see an opportunity and jump on it.


  • Like 2

Share this post

Link to post
Share on other sites

If they build or are building a land version of this for nugget detecting I surely hope they have auto ground balance rather than the manual gb seen here on the beach machine. I would be interested in a nugget version of this machine for sure, look how light weight it is!!!

  • Like 2

Share this post

Link to post
Share on other sites

Sounds like a good one. Forgive my ignorance,   I was under the assumption  that pulse detectors ignored the ground.  Does anyone know why this unit is not suited for mineralized ground, but only salt water  beaches? TIA

Share this post

Link to post
Share on other sites

Pulse induction detectors do not ignore the ground. They are less affected, yes, but not immune to mineralization. That is exactly why ground balancing pulse induction metal detectors exist versus machines like the Tesoro Sand Shark, Garrett Sea Hunter, and White’s Surf PI, which do not ground balance. Those units are for beach use because they can’t handle hot rocks and severe mineralization. All Minelab PI detector’s ground balance, as do the White’s TDI and Garrett ATX.

Long story short a beach model does not need a ground balance circuit that works as well as that needed for gold prospecting, for example. A ground balance circuit is not needed in mild ground and can rob depth if used where not needed. That is why the White’s TDI lets you shut off the ground balance. Here is my attempt at explaining the subject.

  • Like 4

Share this post

Link to post
Share on other sites

My GP Extreme is sensitive to the wet beach sand. Is this due to a sample timing too short, ground balance, or the type of coil I was running (platypus)? Is it typical of the GPX series as well or do they have settings to normalize there?

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By Dances With Doves
      how is the mineral content in lake tahoe. Is it bad?I   heard that the land on that lake is highest price in country.Canandaiugua lake by me is  second so I hear.Canandaigua is where Susan b Anthony had her trial. I found a steamer tag 1865-1889 from a ship by that name that I think burnt.
    • By Steve Herschbach
      With thanks to PPP, here is the new official Fisher Impulse AQ Facebook page:

      And phrunt found this:
      Organization: FIRST TEXAS PRODUCT Presumably we will see the first full announcement information on the Facebook page since that is how things seem to be done these days. Interesting there has been no mention of the main Fisher company Facebook page.
    • By Steve Herschbach
      With the exception of the battery cable sticking out the back I really like the look of this detector. And after swinging a 7 lb Garrett ATX this 4.2 lbs of well balanced detector is going to seem like a dream on my arm. I ditched both my ATX and my 7.2 lb Minelab GPZ 7000 a couple years ago in a fit of passive-aggressive protest over those heavy beasts, and swore not to buy another pulse machine until somebody made something more in line with the ergonomics I desired. The Impulse AQ tips the scales at a little over 4 lbs, but that is largely because of the 12" round coil. A smaller coil is a distinct possibility, as is the ability to belt mount the battery. That's the benefit of that funny looking battery cable arrangement - external batteries. In any case, good enough for me and a huge improvement of what I'm used to. The price remains to be seen, but it has a good chance at coming in under $2000, making the new Fisher Impulse AQ one of the best contenders so far in my Under 4 lb, Under $2K Challenge
      Fisher Impulse AQ Data & Reviews

      Fisher Impulse AQ discriminating pulse induction metal detector
    • By Bill (S. CA)
      Hey Rick, heard anything more from El Paso as to their return to work?
      Fisher Impulse AQ Data & Reviews

    • By fredmason
      I may have missed this issue..you know I am not very smart.
      will the prospecting, nugget finding version be wireless?
       I could not, would not buy another detector that doesn’t have a module.

    • By BigSkyGuy
      Many of you have expressed a desire to know how well the Impulse AQ will function for land use. One option is to wait until the unit is released. I know, no fun! The other option is to analyze the information we do have on the unit and on PIs in general, combined with information from the scientific literature and various forum posts. I have done such an analysis which is a bit long, but I will summarize the findings followed by how I arrived at the conclusions. The places where I believe the unit will be effective include the following:
      Black sand beaches (mainly coarse unweathered magnetite)
      Soils containing mildly weathered granite and other felsic igneous rocks (I know this appears to conflict with Alexandre’s post, but I will elaborate below)
      Unweathered or mildly weathered basic igneous rocks (basalt, gabbro, etc.)
      Places where I think the AQ will struggle include:
      Weathered basalt and soils derived from basalt
      Some fine-grained volcanic rocks such as rhyolite.
      The basis of my groupings above is the published magnetic susceptibilities (MS) for various minerals and rock types and on the concept of frequency dependent MS which is a very important consideration for PI detectors.
      MS is a measure of the magnetization of a material in response to an applied magnetic field. Frequency dependence is when the measured MS varies when different frequencies are used for the induced field. Minerals with high MS are responsible for the “mineralization” when speaking of metal detector performance. Three minerals are responsible for most “mineralization”; magnetite (Fe3O4), titanomagnetite, and maghemite (ꝩ-Fe2O3). The MS for these minerals are orders of magnitude higher than for other iron minerals such as hematite (α-Fe2O3), goethite, biotite, pyroxenes, etc. The relative proportions of these minerals within different rock types determines the MS of the rock. Ranges for different rock types are shown in the table below.
      Rock Type
      Magnetic Susceptibility Range (10-6 SI)1
      Igneous rocks
      Average felsic igneous rocks
      Average basic igneous rocks
      1.       Compilation from Hunt et al. (1995)
      Minerals with high MS are responsible for the poor performance of VLF metal detectors. Hematite within soils is typically red, but given the relatively low MS, is not particularly problematic to metal detectors. So, red soil is not always bad!
      The MS of soil is a function of the parent rock from which it was formed (see table) and the degree of weathering of the iron minerals present. Soils formed from basic igneous or volcanic rocks such as basalt generally have higher MS than soils formed from felsic rocks (rhyolite, granite, etc.), but it depends on the specific rock. For example, some granites have low MS because they are dominated by ilmenite (S-type granite) as opposed to magnetite (I-type granite). Ilmenite has low MS. Geologists use MS to map different types of granite. Da Costa et al. (1999) found that the basic volcanic rocks from southern brazil produced soils containing maghemite (high MS) and hematite while the intermediate to felsic volcanic rocks produced soils containing goethite (low MS). However, there are examples of basic rocks having low MS and felsic rocks with high MS, it all depends on the mineralogy, the grain size, the degree of weathering, subsequent geochemical reactions during and after soil formation, and other factors.
      Typically, the smaller the grain size, the higher the MS. Therefore, a volcanic rhyolite which has a much smaller grain size than its intrusive equivalent granite, will have a higher MS even for an identical magnetite content. Smaller magnetite particles also weather faster than coarser grains. Magnetite can weather to maghemite on exposed outcrops. Maghemite is an earthy mineral that forms very small grains. The small grains produce a superparamagnetic domain which results in frequency-dependent MS which causes problems for even PI metal detectors, especially PIs which do not have the ability to ground balance (such as the Sand Shark and Impulse AQ). Magnetite can also form very small grains, and if small enough can also be superparamagnetic. However, magnetite tends to be coarse-grained while maghemite tends to be very fine-grained.
      Maghemite tends to form from magnetite and other minerals in tropical climates or where tropical climates once existed. The “bad ground” in Australia is due to the presence of maghemite, which is a brown to brick red mineral. Maghemite is less common in the US but is present. Magnetic anomalies found at the National Laboratory at Oak Ridge TN were found to be natural deposits of iron-bearing colluvium (sediment which has accumulated at the base of a mountain range) which has oxidized to maghemite (Rivers et al., 2004). Maghemite and hematite can be created from goethite (α-FeOOH) in response to the heat generated by forest fires and slash and burn agriculture (Koch et al., 2006). Therefore, poor detecting conditions can be created in such areas.
      The bad ground at Culpepper VA is probably due to maghemite, but I have seen no information to confirm this. Geologic maps of Culpepper Co. do show the presence of basic bedrock, such as basalt and dolerite.
      The granite that Alexandre mentioned as giving the Impulse AQ problems may be an I-type granite (magnetite rich) in which the magnetite has partially weathered to maghemite.
      The reasons for why I think the Impule AQ will or will not work in various soils/rock types is summarized below.
      Soil/Rock Type
      AQ Works?
      Black sand layers on beach
      Black sand is derived from physical weathering of igneous and metamorphic rocks in upland areas and consists mainly of relatively unweathered magnetite.
      Soils derived from felsic igneous rocks
      Felsic igneous rocks with high MS, tend to be coarse grained and even when dominated by magnetite (I-type) do not typically produce maghemite unless highly weathered.
      Soils derived from basic igneous rocks
      Probably not
      Soils derived from basic igneous rocks tend to be dominated by maghemite.
      Basic igneous hot rocks
      Basic igneous rocks such as gabbro can be a problem if weathered or partially weathered to maghemite.
      Felsic igneous hot rocks
      Unless highly weathered, felsic rocks are dominated by magnetite which the AQ should be able to handle
      Volcanic hot rocks or black sand beaches (i.e. Hawaii)
      If fresh, the main source of MS is magnetite. If weathered or partially weathered to maghemite, the AQ may have problems. If very fine grained even unwethered volcanic rocks may present a problem.
      Da Costa, A.C.S, Bigham, JM, Rhoton, FE, and SJ Traina. 1999. Quantification and Characterization of Maghemite in Soils Derived from Volcanic Rocks in Southern Brazil. Clays and Clay Minerals, v. 47, no. 4, p. 466-73.
      Hunt, CP, Moskowitz, BM, and SK Banerjee. 1995. Magnetic Properties of Rocks and Minerals. In Rock Physics & Phase Relations: A Handbook of Physical Constants, Volume 3.
      Koch, C.B, Borggaard, OK, and A. Gafur. 2005. Formation of iron oxides in soils developed under natural fires and slash-and-burn based agriculture in a monsoonal climate (Chittagong Hill Tracts, Bangladesh). Hyperfine Interact 166, 579–584.
      Rivers, JM, Nyquist, JE, Terry, D.O., and W. E. Doll. 2004. Investigation into the Origin of Magnetic Soils on the Oak Ridge Reservation, Tennessee. Soil Science Society of America Journal, Vol. 68 No. 5 p. 1772-1779.

  • Create New...