[size=large]In mid-April of '85 White's introduced their first auto-tracking model, the 6000 Di Pro. Shortly after the dropper their manual ground balance model, the 6000 Di Series 3. and that brought a lot of requests from detectorists to bring it back. White's did, but by simply renaming it the 5900 Di Pro. The 5900 Di was Manually Ground Balanced and the 6000 DI Pro featured AutoTrac.
I preferred the 5900 Di Pro because they didn't have the AutoTrac working quite right on their first release. Besides, I prefer to be in control of that function. These two models progressed through some variations, such as the Di Pro Plus and into the DI Pro SL versions in the black housings. Most of the effort was directed at perfecting their top-end analog model the 6000 Di Pro SL and it was sometimes reflected in some letter reference on the shipping box or inside the battery door, such as 'XB' and finally, the 'CB' revision, which was the last one. The CB stands for Composite Board, and eventually the 5900 Di Pro SL incorporated this same CB board revision and had all the same performance as the 6000 Di Pro SL with the only difference being the method of Ground Balance.
The Eagle, the Eagle II, then Eagle Spectrum were top-of-the-line models using the same bigger control housing and the 4-C cell battery system, and then in the spring of '94 White's introduced the Spectrum XLT. The XLT used a smaller-size housing, was lighter and better balanced, and was powered by the drop-in 8-AA battery tray (or rechargeable).
The Classic series evolved into this same control housing size and many avid hobbyists had wished form the smaller package for their analog 5900/6000 class models. Unfortunately, White's failed to deliver to us a manually GB'ed model in the compact housing, but their engineers went to work and made a new model with the goal to match or better the performance of the 6000 Di Pro SL in a model that would fit into the smaller housing of the XLT and Classic series. They met that goal with the introduction of the 6000 Pro XL.
Note that they dropped the 'Di' , and went to the XL suffix in the name. This model only carried over about 15 to 17 parts from the former analog unit, the 6000 Di Pro SL, and was basically engineered from the ground up, They eliminated the useless Volume control (Target Volume) and peaked it internally at a point just slightly more than the former analog offering. They also enhanced the operating power or sensitivity a little.
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