I have hundreds and hundreds of hours on the F5 if you have any questions. Google Mike Hillis bible. The box by todays standards is pretty big. Balance with the concentric is superb. The layout is awesome. I only wished they swapped the phase lock (ground balance) button and the tones button....would make it more comfortable to GB. Its not a deep machine. It can be chattery even when laying on the ground. I often wished I could have a F75 with the F5 layout. The knurled nut on the coil wire can be irritating by its lack of grip. Battery life is excellent.
Remember to hit the freq button to find the quietest channel. The pinpoint is super accurate on the concentric. The eliptical concentric was my favourite coil.It balances so well and has good coverage with the shape. Mike spoke of a '9++' depth on the gain by turning the gain hard up against the stop then backing it off a little.
If I was doing it all again I would run much quieter gain & thresh. Listening 'through the noise' was exhausting at times.
It breaks down small and light, a bonus for a backpack. Be gentle removing the battery cover, its a bit crappy. The face is also quite easily scratched.
At the time I only wore headphones from fisher (built in independant volume). the lack of volume was a bit dissapointing considering all the buttons!
Any iron grunt (low tone) amongst the high tones is usually rusty iron. There is a significant loss of depth between 4 tones and one (test drive a coin).
The continous rotating ground balance button was a bit unecessary as I usually just ground balanced anyway rather than try and match the phase by turning the knob.
The ground balance button also has an UNUSED push button feature .Why didnt Fisher use that as the phase button?
I ended up buying a F75 and sold the F5. The difference is astounding. Saying that, I miss the interface sometimes and miss a lightweight back up machine.
I would dearly love another interface like that . Its an interesting and unique machine. The F11,22 etc in my opinion are a bit soul less
Do yourself a favour and use sensible gain settings. Also have realistic depth expectations.
I hope you got a good deal. The teknetics range (also First Texas) represent excellent value.
Keep us posted
Chub