Just curious. Is there a rule of thumb, always have them sounding different? Have one with more lows other with more highs? Doesn't matter?
Most of the time. If I'm looking for a little more flavor though, I'll swap the head for another one and keep all the exact same settings so the only difference is the head. Did this on a few recordings that had a rectifier on the hard left and 6505 on the hard right
Uhhh, what?
For instance, Say I record the first passage through with a 6505 and Mesa Cab with a 57 on the grill. Say every knob is @ 6 o'clock.
Once that passage is recorded, swap out the 6505 head for a Mesa Triple Rectifier head and keep the same settings. all knobs @ 6 o'clock as well and record that passage.
Then pan one hard left and the other hard right. This way,
the rig stays the same practically except the head change so you really have this slight tone tonal difference that really fills out the rhythm guitars.
Of course, you'll have to make sure the level of the signal matches that of the other head but that's not a big deal or hard to do. This is a method I'll usually do If I'm looking for more broader range guitars than just the exact same rig panned left and right.
The settings of one amp have nothing to do with the same settings on another. It doesn't work that way. In the case of 5150 and Recto specifically, I believe the Recto has an active EQ, which the 5150 does not. Small changes have more drastic effect on the Recto's EQ compared to the same degree of change on the knobs of a 5150 because of that. Regardless, if you have two amps with the same settings, the only thing that is the same between them is what the knobs are set on, but the tones will be completely different, not slightly different, unless they are voiced similarly or from the same basic original design (like a JSX and a Triple XXX, for example).