Dolby NR encoding - did it ever work

I used a Nakamichi BX300 with regular maintenance (de-mag, roller cleaning) for years and the Dolby C was amazing…you could instantly verify this since it was a 3 head player. Could be that Nak just did it right somehow…the machine is retired (no room in my rack..damn…) but served me well!

BTW Dolby SR is state of the Art and approaches digital for S/N ratio.

I'm with Wolf---the Dolby C in my BX300 is great. The deck is great with metal tape (I've used TDK and Sony), by the way. But the BX series Nak's design has a flaw---it's transport is not the most robust. I believe the CR series Nak's may be the one to get.

I will partly correct what I said before. I think, my cartridge and new cables were not fully broken in when I was making comparisons while recording from my Spacedeck turntable, though they had over 150 hours on them.
First of all, the deck cannot really compete with the turntable. The dynamics gets compressed a little but the biggest difference is in the soundstage - it loses both depth and width, but the deck still sounds very very good. The same can be said about the difference between recordings made without Dolby B and with it. They do sound better without it even though they are noisier, of course.

If anyone ever experienced the dynamics of their recordings being compromised while using Dolby B, C or S, then your machine was not calibrated for the tape you were using. 
Once calibrated and proper recording levels set Dolby would have no ill effects on your recording. 
This is funny because I just had this conversation with another audio nut. I have hundreds of tapes many that are 40 years old that sound excellent and were made with Dolby. 
That said I do know the sound of a machine that is killing the Dynamics of your recording when using Dolby. Nearly all of my Teacs did this. It wasn't I until someone showed me their Advent 201 in which you could calibrate the Dolby that I realized how good it could be and how bad mine were. Since that time I have always owned a deck that allowed calibration of the Dolbly NR system. 
I am really surprised at the number of audiophiles who snub cassettes as 'mid-fi' crap. Properly recorded cassettes are very enjoyable and convenient. I use my ancient Nakamichi all the time with excellent results.