I have the RH450 and a Markbass F1 (see sig). The primary voicing of the TCE amp is not ideal for DB, at least for jazz, IMO -- perhaps it would suit other styles of music.
It can be made to work, though, and this is where the fantastic EQ section is very much your friend. I set mine by using a large-diaphragm condenser microphone on the bass, in a fairly
"classic" location (in front of the treble-side, between the f-hole and the end of the fingerboard), recorded various 3 octave scales, and then used that as my reference for comparing pickup-fdeck HPF-Pre-RH450-BFM Jack 12, with mic on the speaker, dead centre, with the bass as off-axis as possible and me shielding as much as possible. I made all recordings in Logic-Pro and used a spectrum analyser to inform EQ adjustments until I had it as close as possible to "my bass but louder", then used this as a preset, and a basis from which to adjust for various rooms, etc.
Worked pretty well, but at the end of the day, the Markbass has a much flatter and wider inherent voice which makes it the more suitable of the two for DB, at least for me. I love the RH450 on EUB and BG, but I never double (at least I haven't to date), so I can keep separate amps. I use the same cab for everything, though -- the Jack 12 is a great cabinet, very efficient, with great tonal clarity, and very light (if a little bulky in its linear dimensions).
If you do double, and can afford the time it takes to get the DB tone you want from the RH450, it's a fantastic amp and makes for a simple rig with all the on-board whizz-bangery and little need to carry much else.
Last thing -- it has a 1 MOhm input impedance which works well enough for most piezo DB pickups, but I still wouldn't use it without my fdeck HPF-Pre, which frankly can make almost any bass amp at least usable for DB.
Hope that's helpful.
