Whites Classic, II, III, ID, and IDX Modifications

[keith777]

Hi again guys.

just wondering. has anyone ever done the frequency & normal-beach switch modification to there white's classic 11

thanks in advance guys......

[keith777]

Thanks Guys........
i came across this late last night.



Whites has used many different coil designs and
windings over the years. While the housings and connector
may be the same, the inside is totally different. This
discussion will focus on designs used in the last 20 years
because there are still tens of thousands of 20+ year old
Whites detectors in use. The Internet has created many
problems for detectorists. Most of the time common sense
has taken a back seat to impulse buying, the thought
of getting a "good deal".

Look at the outside left ear of your search coil
(where the bolt goes through it). You'll see a winding
designation stamped into it, i.e. 6B, D5, G, 8B, etc.

D4 and D5 coils were used on the 6000/D and 6/DB
detectors ONLY! They cannot be used on any other units.
The D4/D5 coils were available in 8" and 15" only.

B4 and B5 coils were used on the 4/DB and 5000/D
detectors only! They cannot be used on any other units.
The B4/B5 coils were available in 8" and 15" only.

6B coils were in use since the "series 2" thru
"series 3", Pro units, the Classics, and at present on
the Classic I SL and II SL. 6B coils were available in 4",
8", 10", and 15".

F coil was made only in a BM256 (Blue Max 10"). This loop
is totally interchangeable with all 6B coils above. It was
manufactured to give performance to units which use the 6B
coil similar to the BM950 coil is use today.

G, HI, 8B coils are known as the (Blue Max) BM350, BM600, BM5.3,
BM800, BM7.8, Royal 800, BM950, BM1500. These coils are
interchangeable. THESE COILS ARE NOT MADE TO BE USED ON UNITS
WHICH NORMALLY TAKE THE 6B DESIGN! TRYING TO USE THESE COILS
IN PLACE OF THE 6B COILS WILL HAVE VARYING RESULTS. Some units
may or may not ground balance properly (even if re-adjusted),
but disc settings will be off and target ID's will not be accurate!

[Tim]

The BLUE MAX 950 is the one to own I believe. Not tried one myself. I did build a 10 DD. Didn't like it much. To many pops and chirps over iron here in UK fields. For me I preferred it with concentric coil. With a good set of headphones you can run very little discrimination.

When setting you machine up test it with small thin silver on its edge. Enough discrimination to fully discriminate most iron will half the depth of that small target. But if you use the right headphones you can here a difference in the tone before its fully discriminated out. This is where the DD failed for me.

That's interesting koala. Some trains of thought say a DD will be better in trash/ironstone.
Keith also the BM256 coil will work (DD).

[IDXKevin]

Not all 6.59 will work. The phase difference on the 6B coils (stamped into the lug) will not ground balance.

The BLUE MAX 950 is the one to own I believe. Not tried one myself. I did build a 10 DD. Didn't like it much. To many pops and chirps over iron here in UK fields. For me I preferred it with concentric coil. With a good set of headphones you can run very little discrimination.

When setting you machine up test it with small thin silver on its edge. Enough discrimination to fully discriminate most iron will half the depth of that small target. But if you use the right headphones you can here a difference in the tone before its fully discriminated out. This is where the DD failed for me. By the time I turned up the discrimination enough to not be digging too much iron I was getting less depth on those small targets than I did with a 8" concentric.

On fairly quite fields I did find my finds rate went up if I used 0 discrimination. When locked on to a signal I would then turned up the discrimination and check if the target was iron.

There's a few techniques to avoid digging iron on those louder beeps. Listening to the sound as you lift the coil and sweep off centre being the best. Iron bars also give a good signal on the ends. Finding the centre in pinpoint mode and swinging over it will avoid digging these.

If you are not digging a few odd shape bits of iron your probably using a bit to much discrimination.

Used to its max its not far behind modern machines on depth. Discrimination isn't the best. As long as you are willing to dig a bit of iron you will be finding more than most that use modern machines and dig by numbers

Used mine for a couple of years and had some cracking finds with it

He is correct,the older 6b coils will plug in but won’t function properly. The Black Max and Blue Max 950 pancake coils are great! As is the Royal 800, Blue Max 800 and Black Max 5.3(Bullseye Coil).

[Koala]

Not all 6.59 will work. The phase difference on the 6B coils (stamped into the lug) will not ground balance.

The BLUE MAX 950 is the one to own I believe. Not tried one myself. I did build a 10 DD. Didn't like it much. To many pops and chirps over iron here in UK fields. For me I preferred it with concentric coil. With a good set of headphones you can run very little discrimination.

When setting you machine up test it with small thin silver on its edge. Enough discrimination to fully discriminate most iron will half the depth of that small target. But if you use the right headphones you can here a difference in the tone before its fully discriminated out. This is where the DD failed for me. By the time I turned up the discrimination enough to not be digging too much iron I was getting less depth on those small targets than I did with a 8" concentric.

On fairly quite fields I did find my finds rate went up if I used 0 discrimination. When locked on to a signal I would then turned up the discrimination and check if the target was iron.

There's a few techniques to avoid digging iron on those louder beeps. Listening to the sound as you lift the coil and sweep off centre being the best. Iron bars also give a good signal on the ends. Finding the centre in pinpoint mode and swinging over it will avoid digging these.

If you are not digging a few odd shape bits of iron your probably using a bit to much discrimination.

Used to its max its not far behind modern machines on depth. Discrimination isn't the best. As long as you are willing to dig a bit of iron you will be finding more than most that use modern machines and dig by numbers

Used mine for a couple of years and had some cracking finds with it

[keith777]

i am sure i read some were that once the mods were done you could use other white's series of coils?

[IDXKevin]

Well....unless you added different frequencies somehow,the 6.59khz coils are still the only ones that will work properly.

[keith777]

Hi again guys.

all the mods are now done to my classic machine now. what exact other coils will it now accept. just someone has some spare whites coils laying about and has offered to give me one if it will work with the machine.

thanks in advance guys.........

[thekevin]

Are there any reputable people in the US doing this mod for people who don't want to tear into their own.

[DavidB]

I had it that way already but put the trimmer back in to iron out some other changes. I am adding a opamp and a mosfet to isolate it better from the other channel reference, expand the linear range and eliminate the affects of having long wires on the control. I do this stuff all the time.

[SVEN1]

Look at the board, look at the trimmer traces. Are two trimmer solder pads connected, then you only need two wires, just duplicate the connection at the pot leads. You can always use three wires as well and connect all three wires to the pot and duplicate the same connections at the pot.

[Nandor]

Looks very nice, great job.

[DavidB]

Classic I with a lot of changes



Moded this one to death. All metal in one ear and Disc in the other. Added an additional SMD board which contains a LT1615 boost regulator followed by a LT1962 linear LDO regulator and a TI 2426 rail splitter. The board also contains an additional audio output channel. I upgraded main board components U1 to NE5534, U3-TLC2262, U5 LMC662, U6 OP291. I removed U9-LM2930. I modified the filter components for better response and lower noise. I converted the batter test half of U7 to an additional tone oscillator so I could have a low tone in the all metal ear and a high tone in the disc ear. The half of U6 that was used for the old rail splitter is now the additional Threshold amp for the all metal side. I reconfigured U5 to an auto tune all metal circuit with half used for the SAT feedback and added an auto tune switch so it can be switched off for balancing. It now has 5 controls. Disc, Sens all metal, Sens Disc, Thres all metal and Ground Balance. The internal power is now +5V and -5V so it now has 10V on the transmit oscillator. The new battery supply is 2-3.7V lithium Ion batteries in series. The batteries are rated at 5 amp hours and the total current draw is less than 45 MA, so that's better than 100 hour battery life on a charge depending on how accurate the rating is. The detector is working on the bench but I need to add a buffer between the Ground balance control at the board so the capacitance of the long wires does not affect the phase. Quite a bit of work but it's been fun.

[SVEN1]

It would help if you put a piece of schematic you refer to, or at least a name and revision.
In any case, the SAT circuitry is looking at very high impedance, and for that reason only short leads and FET/CMOS switching is recommended. So potentiometer is off menu.
High impedances and long leads do not mix well because of capacitive coupling to just about anything. Having a few values to switch between electronically may work fine. Also having a switchable reset resistor of small value is a very good choice.

I used a pot for SAT and had no issues, worked just fine.

[Davor]

It would help if you put a piece of schematic you refer to, or at least a name and revision.
In any case, the SAT circuitry is looking at very high impedance, and for that reason only short leads and FET/CMOS switching is recommended. So potentiometer is off menu.
High impedances and long leads do not mix well because of capacitive coupling to just about anything. Having a few values to switch between electronically may work fine. Also having a switchable reset resistor of small value is a very good choice.