I bought one of these but V3 last week and I can tell you I really enjoyed using it for setting my car audio's gain. My current setup consists of head unit, loc, eq/linedriver, and amps. I used it to set max volume on head unit and gains on each of the other devices all the way to the amps. Worked like a charm and the result on screen matched when my ears perceived clipping. I didnt mind the purple waves on the background so I did not upgrade the firmware.
You can set gains on all your devices with no worries except when you get to your amps, because this unit can only accept up to ~40 volts and it might get damaged if you go any higher than that. What I suggest is buying an x10 probe which you can get on
ebay or
amazon and search for a 3.5mm to BNC female adapter to fit on your DSO Nano. With the x10 probe you can put up to ~200volts I believe... I did not have to use a x10 probe because my amp was putting out only 29 volts before it clipped so I never got past the 40 volts, but I still ordered one just in case for future.
Now the V3 DSO Nano I got has a 3.5mm mono input, so I had to buy some adapters, and also made my own cables, such as 3.5mm mono to two gator clips. Also, bought a 3.5mm mono to RCA adapter. And for your x10 probe you would need a 3.5mm mono to BNC female available on
ebay. Also, it doesnt come with a mini usb(not micro) to charge it, so get one of those as well... With all this I think you have more than enough to set gain on all your equipment.
I would recommend it if like me you are on a budget and you are only using it as hobby, say for your car's audio gains.