Hey Jazzyvee,
That's the beauty of our active electronics package - no matter where you set the output trimpots, master volume, or pickup volumes, the TONE and dynamics are unchanged. But as you have found, what does make a difference is the next piece of gear in the chain and how much level it wants to see for optimal sound.
As an example, I run my basses set to about maximum output which is almost full line level. I can drive a power amp straight off the bass to maybe 80% of it's rated output (just an estimate). For recording I pass this hot level through my REDDI di box which also has a bit of gain and a trim pot. From there I go into a line-level input or directly into my AD converter at home.
If somebody wants to pass my bass through their preferred preamp, I simply trim my master volume down to the point where the output is what their particular gear wants to see as an input.
So I think my method above might be hitting the REDDI a bit harder than it was meant to be hit. It has a tube in it and it may be adding a bit of fur to the sound because of the level I'm driving into it... But I like whatever it's doing.
It takes some experimenting to find the best level for each piece of gear in the chain. This is also a "signal to noise" thing. If you have a large amp which you are feeding too weak a signal at the input you would need to turn the volume up so much that the accompanying noise might become a problem. It seems your Mesa and Peavey's like a hot signal so go ahead and give it to them! At some point these inputs would probably start clipping and add unwanted distortion (or ... you may like it!). Once you find the breaking point you can back it off from there and leave yourself some headroom for the widest possible dynamic range and signal to noise ratio. All the while your bass will be sending it's GIANT TONE at whatever output level you've chosen.
Make sense?
Jimmy J
