First and foremost, a huge thanks to
MrB, who has sent me a plethora of clips, and also has taken the time to measure his PCM70 with a pulse generator. He supplied me with more high quality clips and numbers than I could ever dream of.
Ok, here are the details:
- The PCM70 is quite a wonky unit. There is a big difference between the left/right outputs, and it changes with preset configurations and panning of the voices. The outputs have a +-1.5 dB margin of error according to the service manual (which is a lot). From the 3 units that I have good enough clips of to measure this, it's always the right channel that is lower in volume. Listening carefully to soundboard recordings of Lukather, his units appear to have this "issue" as well. I suspect it's partly due to tolerances, and also the summing circuit at outputs that enable mono operation from one jack. Anyway, I've matched this behaviour to 0.05 dB accuracy across both presets.
- The diffusion in the Axe-Fx sounds quite different to the Lexicon. I've confirmed that the diffusion parameter in the PCM70 is not a mix control, but a time control. I measured the length of the diffusion on PCM70s Circular Delays preset, and then matched the length in the Axe-Fx. The diffusion in the PCM70 causes the actual delay times to drift. I figured out a neat way to capture this.
The presets have been converted to multitap delay blocks. Put them in your
"Documents\Fractal Audio\Axe-Edit III\blocks" folder. They are meant to be used in parallel to the dry signal patch.