Which Came 1st: dbx Type 1 or dbx Type 2

Which came 1st? dbx Type I or dbx Type II NR?

I've used dbx Type II NR for years.

Then I discovered dbx Type I NR. dbx Type I completely(?) eliminates all the nasty audio artifacts of dbx Type II NR.

I plan to re-record all my R2R tapes into dbx Type I NR.

Are any of you guys using dbx Type I NR?

MLStrand56