New tubes or new preamp?

Dump the ARC pre and get one that is more lively. I just went through this with a ARC SP-9 MarkIII. A pre-amp change absolutely transformed my system.

"07-01-13: Brrgrr
Russ69, What did you get to replace it?"

I'm embarrassed to say that I put a NAD C162 pre-amp into this system (not my main system). It's my back-up pre-amp. The NAD is full sounding with good bass. It kind of funny because I have a Mac MC402 amp in this system (my most expensive component). Anyway, I have had the AR pre-amp in and out of many systems and it is very detailed but in the wrong system it just doesn't have any bounce. You system sounds like it has the same problem. Maybe you can borrow another pre-amp and see if that does the trick.

Rrog says: "Did you leave the SP-9MKIII powered on all the time? If you did not leave it powered on you never heard it. So now you think the OP should dump his Audio Research preamp and get an NAD?"

I have had the ARC SP-9MKIII in 3 of my systems and listened to it in 2 of my brothers reference systems. I'm pretty familiar with how it sounds. I also have a ARC LS-2 and a Cary SLP-98 to compare it too. Oh and I guess the old NAD and another pre. Anyway, in the wrong system it can sound a little dry. I'm thinking that is the OPs problem.
I never recommended the NAD, I told him to borrow a different pre-amp and try it out. The synergy with the ARC pre-amp wasn't there in my system, maybe your system is not like mine and you have different results. I'm just passing on my results, if you don't find that useful, for your system, then maybe we both learned something.

Thanx, Russ