2 prong power corded stereo equipment and electronics.

[vertamps]

With so many amplifiers in the music world, utility, power tools and pc's with 3 prong grounded plug cables im confused why there are so
much other appliances that use 2 prong non grounded cables.
Particularly high powered stereo equipment like my Technics SA-700 from the 70's with 100watts per channel output and even new stereos still non grounded.
Even most all televisions are non grounded.
Granted alot of consumer electronics is encased in plastic and you might not touch a lick of metal its always on my mind.

[g1]

A lot of the newer 2 prong stuff is actually polarized plugs. The blade for the neutral is wider and it will only fit into the receptacle one way.
Also, as you mentioned, whether there is metal chassis that the user can come in contact with is a factor.

[eschertron]

A lot of the newer 2 prong stuff is actually polarized plugs. The blade for the neutral is wider and it will only fit into the receptacle one way.

Shucks, I thought the wider prong was a manufacturing defect and always end up cutting them down to fit!

edit: Of course, this doesn't answer the ground prong question. I'm guessing if there's nothing in the device that needs to be "earthed" then there's no need for the ground. Still makes me feel a little uneasy, though. Like the drill stand I bought at a garage sale today. The drill (an older drill, with the all-metal construction) has had the ground prong CUT OFF at some point in its history. Will I replace the plug connector? Yah, if only to stop the voices in my head.

[52 Bill]

I would think that the main difference is physical contact to the item that is plugged into the wall. Unless you use wireless you are connected to the chassis ground via the guitar stings or mic case.

I can't remember the last time I had to touch the tv to turn it on or change the channel.

[Mick Bailey]

Ungrounded devices have to be compliant with IEC Class II. No earth is required is required as no single failure can result in a shock. They were originally referred to as 'double insulated'. I remember buying a Wolf power drill in the early 70s that used this as a selling point and had no ground (earth) connection - a novelty at that time.

Ungrounded audio equipment solves one problem with items that can end up being connected together; no ground = no ground loop.

The fact that something may have a metal case still means it has to achieve two layers of protection internally if it's compliant with Class II.