All the various API mic preamps have the same type of tone and are pretty much the same except in size and features. Any real difference that can be heard is likely due to what specific transformers are being used and how old or new the API 2520 OpAmp's are.

AudioGaff, it is correct. There really isn't any difference between any of the API microphone for amplifiers except for the earliest units used in API manufactured awful microphone transformer. Of course they still made plenty of hits with those but they weren't known for being particularly good. Later they switched to the Dean Jensen K110 Ceres microphone transformer with a 10:1 ratio winding that they use to this day. The old original 2520 utilized all discrete components where the most recent ones utilize quite a number of surfacemount components on the little epoxy mounted circuitboard. Otherwise they are all identical. They're famous 550 series equalizer also has similar history to them.

I think that that LA sound is just what it is the LA sound which I find to be rather huge and technically impeccable? I've always enjoyed the LA sound but then I've also enjoyed the Chicago, Nashville, Miami, Motown, NYC and the Philadelphia sound so???? I guess I like them all?

It's a woman's prerogative to change her mind
Ms. Remy Ann David