Here's a few notes on the different ways you can master your tracks using analogue gear.
I mastered a new ep by Theo Verney yesterday
Having mixed it in the box at his place he wanted a bit of analogue warmth added prior to main job of mastering. We took his mixes (which correctly didn't have any mix buss compression yet) and sent them via the Apogee Rosetta interface through a Focusrite Red 3 compressor (that's the red rack unit in the pic - just tickling the meters) to the Tascam BR20T quarter inch tape machine (top in the pic) laced with Ampex 456. We put it into record mode and then monitored back the signal coming off tape - and pushed the level so we could hear the effect of tape compression. Pushing the level causes the mix to sound pretty heavy and bassy, so we pushed it just enough to round out the sound, hold in the crashing cymbals and tighten the bass end.
We repeated the process untill all the mixes were on tape. At this point i'd normally just copy them back in via the Rosetta, but we opened up a fresh Logic session and switched the sample rate to 96k. The Rosettas even go to 192k but I thought that'd be a step too far. Still it's the first time i've put masters down at 96k from tape. Copying the mixes back in I then set about passing them through my usual processing chain - multiband, eq, limiter. The slight compression on the Focusrite and tape pretty much meant that there was hardly any limiting taking place in the digital signal path, even to get the dynamic range nice. And the combination of all these things meant that the mixes sounded open in the highs and mids, rounded in the warmth, solid in the kicks.
Theo reports... "The masters sound huge back here, i'm really pleased!"