randall rg100ht with carvin quad x preamp- low hum

[moethepro]

Hi.

two questions for you.

1. I'm using a carvin quad x preamp(rack unit) into my randall rg100ht's(rack unit) fx return, bypassing it's preamp. Using the randall as the power amp.   I have been using this setup for years without a problem.  It really does the trick for my carvin pre.  It has always has had a very low hum coming through my 4x12 cabinet, but it is not noticeable when playing.   Is this a ground loop problem or just because the randalls amp is at full volume (120 watts)?  i rarely turn my carvin preamp's master volume past 2.  .5 to 1 is good for practice and 1.5 for gigs.  It's almost impossible to go past 2, just insanely loud.   

2. I have tried to use my carvin pre into other amps via fx returns: Mesa boogie, crate, and even a peavey pa power amp, but none of them seem to deliver sonically as good as the randall as the power amp.  Is the randall adding tons of presence, dynamics and awesomeness to my guitar sound?  or is it just me?

thanks,
moe

[J M Fahey]

Is the randall adding tons of presence, dynamics and awesomeness to my guitar sound?  or is it just me?

Well, now you know it.
Randalls *are* punchy and aggressive.