Steve, Hello. Just read your post and thought I might be able to help some. I bought one of the first CZ-7's to be released in TN. and may be able to answer a few of your questions. Here goes! First, the CZ-7 was of course the first of the series and had several disadvantages compared to later models, i.e. CZ-7a, CZ-7a Pro, CZ-70 Pro. The major disadvantage of the '7 was the fact that in order to save the last settings used, the machine would use a small bit of power while the detector was off. This doesn't sound like a big deal, but it really ate the batteries compared to the '7a. Also, if you were using the backlight on the LCD the last time you cut off the machine, (and didn't turn off the light first), the next time you fire it up, probably in daylight, the light will come on and there is no way to tell it is on! REAL battery drain! The '7a addresses these two problems with a "last use memory setting in the software" that required no battery drain. Also, if the light was on when the '7a was shut down, it returned to the off setting when restarted. So, the biggest difference in the '7 and '7a was saving battery life. Now for the '7a Pro, while the '7 and '7a required 12 aa batteries, the '7a Pro only took 2 9 volt batteries, and, at around three pounds, was hipmountable. There is little if any difference in performance of these machines as far as depth and stability are concerned. Of course, the '7a Pro is much lighter due to the difference in batteries, but the 2 9 volt cells will not last as long. I happen to be fortunate enough to own all of these detectors, and my advise, for what it is worth is, if you are going to purchase one of these detectors the one to buy is the '70 Pro. The reason for this is it has all the advantages of the later machines, (two nine volt batteries, no drain when off, light is programed to be off when started and it is hipmountable). One great big advantage to the '70 Pro is a fourth tone added for relics! The prior models had a low tone for iron, medium tone for nickles and tabs, and high tone for silver and copper/clad coins. The fourth tone takes the place of the rectangular pull tab, which is where a whole lot of lead and some brass items come in at, and there is a star in place of the tab icon, so when you get a shallow fourth tone hit you can be pretty sure it is a rectangular tab, however, if the target is below, say, 2" dig it and sometimes it will still be a tab, but a lot of times you will be pleasantly surprised. I will add this also, when you discriminate iron on the '7, '7a, '7a Pro, they DO tend to lump the signal into the nickle/zinc (sometimes silver coin) range, and personally, I hate that. However, if swinging better than three pounds all day and buying (or recharging as the case may be) 12 aa batteries when they die isn't that big of deal, then once you learn the quirks, the earlier machines are great detectors. The fourth tone simply allows you to be aware of the fact a relic may be present without watching the LCD. And after all, why lug around the extra weight for a more disadvantaged machine? The Fisher website no longer archives the '7 or '7a manual, but here are the links to the '7a Pro and the '70 Pro, so check them out! This should shed a little light on the subject for you, or help in some small way!!
http://fisherlab.com/hobby/documents/cz-7apro.pdf http://fisherlab.com/hobby/documents/CZ-70proopman_002.pdf I hope this has helped! Great hunting and good luck, no matter what your decision is!!! Regards, Richard.
