I'm taking a shot in the dark here as I know very little about the range but i believe there is the original clarkes and the newer clarkes. As for which one is te or en I don't know but from what I've been told the originals were generally better quality built machines and the newer ones although pretty good are not made like they used to be. Now I could be completely wrong here but that's my guess.
the difference is about £75 on machinemart's website
the en is a gasless machine in a square box, the te is a gas machine in a fancy box. they are both 150amp machines. you could get a regulator to go with 151en if you want to weld with gas and that would workout being cheaper than getting a 151te, and still be able to go gasless if you want
I just got the 151en (Wholesale welding, I'm in Ireland). I got a reg & Mig Argon+5 welding gas.
Works nicely on gas. Make sure to set the polarity correctly. The gasless is useful too. It's sort of half way between arc and mig.
Surprisingly is will do spray transfer with 0.8mm wire on the 3-Max setting.
I'm starting work on a welding cart right now. (Traditional first project)
To clarify, the EN will do gas or gasless.
You do need a regulator. But if you but the TE, you will _Still_ need to get a proper regulator when you get tired of the disposable bottles.
Pretty much everyone seems to say they are a waste of your time and money.
I have no idea if either TE/EN is Better than the other the specs seem the same. So far the EN seems just fine. But since I'm a novice, take that for what it's worth. Within an hour I could weld a test piece of 16 gauge x 1" box section that bent under the tender care of a 10 lb micro adjuster* with only one small cold start on one weld giving way.
*10 lb micro adjusters are also sold under the generic name of sledge hammers.
It takes a bit of practice to get full penetration on 16 gauge without burning through, but it's a LOT easier than trying to arc weld it.