Conrad Johnson CAV 50

A rep from a tube store wrote me and here is what he had to say about a few tubes I was looking at.....
"The EL34 is a pentode. A pentode has a suppressor grid in addition to the control grid and screen grid. The power pentode was developed by Philips in the 1930s. RCA developed the beam tetrode which has a set of beam plates instead of the suppressor grid. At the time Philips held the patents on the power pentode anyone who wanted to build power pentodes had to pay Philips to obtain licensing to build them. RCA developed the beam tetrode so they could build tubes that functioned like a power pentode and not pay the licensing fee. The 6L6 was one of the first beam tetrode tubes. Compared to the EL34 pentode, the 6CA7 and KT77 beam tetrodes will have a little more bass response and sound warmer."

I would agree with that pretty much though I prefer the KT77 to the 6CA7 in my system. I had JJ 6CA7's still have them around as backups. I did also just put in a new quad of Psvane Philips Holland Metal Base EL-34's and they are quite good a bit more top end and maybe a touch more transparent than the KT-77's another nice tube. A bit pricey at $330 but I managed to pick up a "new" used quad for $250.

Jond, a little trust would not be misplaced. After all, I had the CAV50 and, as mentioned, owned most CJ tube gear.
"control amplifier" is how marketing people tried to differentiate it from an integrated amp. 

rolyasm, has your CAV50 been diagnosed yet?

Jazz no mistrust was implied or intended dude I promise! And yes Roly any updates?

It has been a crazy holiday season for us. Finally just decided to stop trying to research all of the other tubes as well and just ordered some  JJ E34L's. I was up late last night trying to find some 12au7 and 12ax7, but started getting pricey since I don't know if the amp will need a major overhaul yet and I read that if I send in the amp for upgrades, often times they replace your tubes for you. So, waiting to buy other tubes but the EL34's should be here shortly and I'll see what they do. I am not hopeful it will fix the problem and not looking forward to shipping that beast to C&J.  I noticed some fuses (auto looking, blade-type) under the hood and behind the EL34's, so maybe I'll take a look at those today and make sure they aren't blown. 
If I keep the amp, which I probably will, I need to start looking for a great pair of speakers for them. I know Klipsch are super efficient, but typically too bright for me. I have seen several reviews and blogs about good speakers for them, so I'll probably start that search as soon as I test the EL 34's. $$$$$ It's always about the cash. Boo for not being rich. haha.
 You all have been very helpful. I'll keep you updated.