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ToddB64, pardon my tardy reply regarding your three models and 'filter' questions..

November 03, 2018 07:49PM avatar

I have the following metal detector models:

#1..Garrett Ace250
#2..White's Classic II
#3..Teknetics Gamma 6000
An interesting set of 'budget' to 'low-end serviceable' models. I have owned all three of these, and actually multiples of each. They all have one thing in common so far as general performance is concerned, and that is they fall in the same 'filtering' category. Therefore, because of that, they also all fit in the same general allowable sweep speed group and that is 'slow-motion.'

Other than that, they each have some very obvious differences in performance and other limitations. For example, here are just a few observations:

The Garrett Ace 250, for example, does feature visual Target ID and it has Garret Metal Detectors audio Coin Alert for the higher-conductive US coins or other targets that fall in that higher-range of conductivity. It features a segmented Target ID, and the Discrimination is also a Disc. segment-controlled selection and not a variable adjustment. It relies on an internally preset Ground Balance setting. Sampling targets it is easily noted that this model has a very delayed audio response and is not a quick-response/fast-recovery design.

The White's Classic II (either the early version in the larger housing and powered by 3-9V batteries, or the latter 'SL' or Slim-Line version in the popular housing with the 8-AA battery slide-in tray) is a very basic model that lacks any visual display. It is controlled by two knobs to adjust Sensitivity and Discrimination. Those are variably adjusted manual controls to allow more fine-tune settings. This model does not work well with White's 'Blue Max' series of coils so the coil selection is very limited. It also relies on an internally preset GB trimmer, but on the 'SL' version Classic II it is easy for a user to make adjustments to tweak the setting for best performance with the coil in use for the mineralized environment they general search. The Classic II is a single tone design, and is designed as a 'quick-response/fast-recovery' type model.

The Teknetics Gamma 6000 is the more advanced and featured of these three models, providing a full range Target ID with both named segments as well as a numeric VDI read-out. It also has a few Tone ID functions. The Ground Balance can be adjusted using a Ground-Grab coil-bobbing technique or it can be fine tuned with Manual Ground Balance. It is also a 'Quick-Response/Fast-Recovery' design, but only to a point as it doesn't process Discriminated targets as efficiently as the other two you named.

Of the three models, and let's presume they each have an 8" Concentric coil mounted, or something very close to that size and type, I think the Gamma 6000 is the better urban Coin Hunting model. For Relic Hunting in more challenging iron nail contaminated sites, the other two don't come close to the performance of the Classic II.

... and checked the operator manuals and might have missed, but didn't see any definitely-stated or recommended coil sweep speed for these. So, how would you classify the coil sweep speed for each, using the same slow, medium-to-fast or fast context as in your post Oct. 13, 2018 12:20 PM of this thread and again in the same context ( 2, 3 or 4 filters), ...
All three of these models are considered 2-Filter designs. The Owner Manuals do not state that, but they are all consistent, I believe, in suggesting the sweep speed should be 1-second to 2-seconds from one side to the other. That's what many, or maybe even most manufacturers state. White's even said the same thing in their manual about the XLT and 6000 Pro XL.

But those suggestions are like many others we might hear about or read about because they are not well defined. Example, 1-second is only half the duration, which is twice as fast as a 2-second sweep. Or, looking at it the other way, a 2-second sweep from side-to-side is only 50% as quick as a 1-second sweep.

Next we have to ask how long of a side-to-side sweep do they consider someone make in that 2-second time? I keep my rods shortened to be about 12"-18" in front of my toe which allows me to overlap better for best site coverage, and it also keeps the detector better balanced than a long, out-reached rod and coil length. Also, other than in a Competition Hunt, my side-to-side sweeps span about a 30" to 36" length. If someone uses a long rod extension and sweep widely to cover 5 feet to 6 feet, and they are doing it in 2-secionds, that is what I call way-too-fast!

A bit more of the general reference to "filter design." When we got our industry first VLF-Disc. models (today called GB-Disc. or simply motion-based Discriminators) in '78, there wasn't really much of a discussion about "filters and filtering", at least until '82. That year Fisher introduced the 1260-X which was quite different for the very brisk sweep speeds required and they referred to it as 'Double-Derivative' which sounded more hi-tech, but in simplified terms it is called 2-Filter. That was really when we say a frequent use of the terms 4-Filter to group the faster-sweep required models and 2-Filter that grouped the slower-motion devices that also produced a quicker response than the 4-Filter models.

Most manufacturers engineers then and today are quick to point out metal detectors have many more 'filters' or 'filtering' that takes place than just 2 or 4. In '87/'88 Compass Electronics introduced their Scanner series which used a circuitry design he called 'Vari-Filter' which was described as a 3-Filter technology that gave the benefits of the then popular 4-Filter and 2-Filter detector designs.

Fast forward to more recent years and some manufacturers do describe some of the circuitry design, but since most average consumers have no clue what is being discussed when the term 'filters' comes up, the manufacturers generally do not mention or refer to it. Most models that worked in that so-called 4-Filter group haven't been made for almost a decade. Almost everything offered today is a slow-motion and generally quicker-response type so the 'filter' topic has generally been 'filtered-out.'

... how many filters do they have??
All three models you listed fall in the general-speaking 2-Filter category.

Also, if you don't mind answering, do you have a source(s) for that latter information, other than calling the manufacturer's and in my case, not having your reputation and connections in the industry, hoping they will divulge?
Source? The best source is simply from hands-on use and evaluation from Bench Testing and then using them afield and comparing their general behavior as well as performance limitations, or impairment, when tying to make them work like a 3-Filter or 4-Filter model in very mineralized ground.

Most detector makers don't like to use references to 'filtering' or the number a model uses because they actually use many filters in various capacities to handle many tasks. Most do make a generalized reference to a detector being a slow-sweep or a fast-sweep, but as I explained earlier, you need more facts to determine hat is fast, how slow you can go, and the impairment of using a too fast sweep on a challenging environment.

Your three models listed are all in what would be considered a 2-Filter circuitry design, but they have many performance differences not really associated with the primary filter reference. For example, NONE of them work like a Tesoro Bandido II µMAX, or even a preset GB Silver Sabre µMAX except for the White's Classic II. White's contracted with Wm. Lahr in California to design a slow-motion/quick-response model to compete with Tesoro because, back then, Tesoro had the solid edge on that market niche. The first Coinmaster Classic series, and the Classic SL versions that replaced them, were perhaps the best offering from any manufacturer to make a model that came close to Tesoro performance.

I'll just suggest any reader forget about using 2 or 3 or 4 Filter references and simply evaluate any model, see how it compares with proven performers on the market now or in the past decade or two, then select them based on their performance for the particular applications and site environment you'll hunt in.


"Your EYES ... the only 100% accurate form of Discrimination!"

Stinkwater Wells Trading Post
Metal Detector Evaluations and Product Reviews
monte@ahrps.org ... or ... monte@stinkwaterwells.com
Detectors: Vanquish 540; CoRe, Relic, Impact & Simplex +; Bandido II µMAX & Silver Sabre µMAX; ORX
Pinpointers: Pulse-Dive .. Headphones: Killer B's 'Hornet' & 'Wasp' ... White's 'Pro Star'
Note: Detectors are listed alphabetically by Brand. Models are chosen based on search site conditions.
*** All working well today to make memories for tomorrow. ***

Edited 1 time(s). Last edit at 11/04/2018 01:15AM by Monte.
Subject Author Views Posted

Does the number of filters in a metal detector affect recommended sweep speed ?

Anonymous User 524 October 12, 2018 08:34AM

The confusion of 'filtering' --- Required Vs Allowable Sweep Speed --- Recovery Time from Rejection.

Monte 484 October 12, 2018 09:20PM

Re: The confusion of 'filtering' --- Required Vs Allowable Sweep Speed --- Recovery Time from Rejection.

Anonymous User 356 October 16, 2018 06:45PM

ToddB64, pardon my tardy reply regarding your three models and 'filter' questions..

Monte 351 November 03, 2018 07:49PM

Re: The confusion of 'filtering' --- Required Vs Allowable Sweep Speed --- Recovery Time from Rejection.

Anonymous User 351 October 16, 2018 09:52AM

Let me try to answer your questions, Todd. .. Lengthy again confused smiley

Monte 427 October 18, 2018 08:13AM

Re: The confusion of 'filtering' --- Required Vs Allowable Sweep Speed --- Recovery Time from Rejection.

jmaryt 310 October 15, 2018 09:56PM

Re: The confusion of 'filtering' --- Required Vs Allowable Sweep Speed --- Recovery Time from Rejection.

Anonymous User 338 October 16, 2018 10:55AM

Re: Does the number of filters in a metal detector affect recommended sweep speed ?

Hombre 409 October 12, 2018 12:05PM

Re: Does the number of filters in a metal detector affect recommended sweep speed ?

Anonymous User 387 October 12, 2018 12:53PM

Just a quick tip on sweep speedthumbs up

Hombre 345 October 12, 2018 02:56PM

Re: Just a quick tip on sweep speedthumbs up

Anonymous User 331 October 12, 2018 04:01PM

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