Thanks in advance for your feedback. I've been playing through a markbass tube 800 head for the last 2 to 3 years and I have no complaints. However, on multiple occasions I have run tube amps( ALL TUBE ) with my bass and cab and the sound was SUPERIOR( IMO ) to my Markbass head. I've tried out multiple ampeg tube heads and orange tube head (ad200b mkIII). Loved them all. I have been tempted to pull the trigger but here are my concerns - 1.) Weight - I have had back issues for a while and I CAN'T own an 80+ pound amp. 50 or less is more doable. The lighter the better. The Orange AD200b is right on my limit. 2.) Reliability - Being that I haven't owned any tube amps I have no personal experience but I seem to consistently read about tube amps having more issues - needing replacement tubes, etc... It seems to me that the only "upside" to tube amps is the sound. Which is worth a lot in my opinion. Is there something else I'm missing? Can anyone share there opinions/experiences on tube amps that would alleviate my concerns? Is there a boutique(or brand name) amp that I'm unaware of that could make me less hesitant? Thanks again for your input.