Conrad Johnson CAV 50


Just acquired this beauty from my father in law. I've never owned a tube amp, so not sure if I should sell it, or keep it and pay him. Anyway, a question for you tube heads. One of the EL34 tubes in slot V7 ( a tube which can have it's bias adjusted, which I assume means the power transmitted) has it's red light constantly on. I turned the bias all the way down and it still flickers. However, I noticed that my left speaker sounded blown/distorted. When I turned the bias up, the distortion decreased. The instructions say to turn the bias down/counter clockwise, until the red light goes out. But, if I do this, it sounds bad. So, my question is this. Is it simply a tube I need to replace to fix that problem, and if I change one tube, should I change them all. Next question is I searched for the EL34 tubes and of course there are a large variety of them. Any thoughts. To me the amp sounds little bright with the Celstion SL6's I am using, so any warmer tubes would be nice. Also, if I were to sell this setup, any idea on what I might ask on pricing? Thanks.
Roly
rolyasm
I would also see if you can swing a pair of used KEF LS50 monitors that have a pretty good low end for monitors (is Stereophile Recommended Component Class A rated in a category that has many $5K+ speaker listed).  Can get for as low as $999 used (currently $1200 + $45 S/H with free $279 stands), new for $1500.  Try to get as much as you can the first go round to obtain highest performing products to delay future upgrades.  If full range is your desired path, their are the Monitor Audio Silver 8s (new $2000 (free shipping, no tax) or used $1400 with $200+ S/H) that are Full-Range Class B recommended.  If you live near Dayton, OH, can get the used version via local pickup to avoid S/H. 
So I am getting my record player back today. Should sound great. I am in need of a pre amp for it and wondering if I should go with a Tube Phono preamp and how that might interact with my CJ. Looks like they start around $180, whereas some of the SS ones go for $50. I would really like to keep it around $200, but willing to go more if the opinions are that it will make a  big difference. 
Also, BradwBradley, I see the sensitivity of the Kef LS50 is 85. Is that going to work well with my amp that doesn't put out a ton of power? 
Hi all, just bumping this. Been playing with the amp and different speakers and having a fun, interesting time experimenting. Just ordered some vinyl that isn't scratched, like most of my collection, but still need a pre- amp or some way to connect the record player as there isn't a phono input. Any suggestions? 

Been researching a bit and this one looks promising for a reasonable price. Puffin Phono DSP. $399 . The  ART DJPRE II Phono Preamp Audio Interface gets good reviews for a $50 product, but it sounds like a lot are using it on basic equipment that just doesn't have a phono on it.