Just updated my stock Quattro coil to an ebay bargain Detech. Fitting wasnt a stright swap as holes in coil needed enlarging by a mm or so. Used for first time yesterday on some well used not very productive but convenient arable land I have access to. Was really cold with wintry showers so only did about 3 hours - the coil def seems to be a vast improvement on standard coil surprisingly and pleasingly the pinpointing was good once I realised the extra power so starting dig 2" back from front of coil. Dug a v good signal 36 suggested depth about 6" thought it was a musket ball turned out to be an old penny right in centre of coil sized plug with the coin visible in plug but impression left in hole!! doesnt get much better than that!! Found the usual bits of junk which included a small gold plated button and a nice smallish lead seal stamped with a lion. Not much to write home about but assured me that coil actually works and still finds small items at depth - button was around 10". Another interesting scenario tho crap find was an old bottle top within a very iffy iron infested signal was getting a regular 20ish id in amongst the -1s and -9s so decided to dig it and ended up with the top and no iron!!!
To conclude am VERY happy with my new coil dont think I will be refitting my existing one
Will post again after my next outing to a better site.
Stu