[ohenry]

A short follow up to my limited tube rolling exercise.

The GE 6GH8A tubes made an improvement IMO.  Certainly worth a try since a guy on epay still has some nice NOS stock for peanuts. 

Also, it seems that the Mullard reissue rectifier is a good fit for me.

Happy listening... 

So... a follow up to the follow up.    I can't stand it, I still brag on the awesome little Ultravalve.  I continue to be amazed with the smooth highs and great bass extension.  It sounds like a hybrid amp.

Anyway, I added a matched quartet of reissue Genelex KT-77's and they sound crazy good after some hours logged.  I'd love to have a set of those renown blue bottle EL-34's, but I couldn't pull the $500 trigger.  I'm content with the KT-77's and have no desire to screw with anything.  I don't even want to turn a screw to see what lurks in that shiny chassis.  I could make it sound different, but not better.

Mr. Frank steered me perfectly when I asked about what to do with powering the big Bozaks.  I'll be trying it with another system that uses more efficient speakers.  Regardless of that outcome, the Ultravalve is staying with the Bozaks.  The worst that could happen is that I'll be forced to buy another one. 

[tipatina]

I've had a number of AVA products over the years. All have been reliable and not at all finicky or difficult to maintain. I found a used ultravalve on AC and it's now the center of my son's system. Original tubes, bulletproof build and exquisite sound.

[eric951]

Thanks for the info. I should of found this thread before I purchased 2 new 6CA7, thinking that one or two where bad.
The funniest thing is that when all 4 JJ 6CA7 where new (about one year ago), I'm one hundred percent sure that I was able to adjust the bias to 1.6v. When I double checked the bias one week later, it was off. I will try to adjust to 1.45

Ron,
I have a production Ultravalve, built Feb this year. I'm all thumbs, when it comes to electronics. I'll leave it up to the experts.
Given your calculations, I'm listening to the Ultravalve at 1.45 volts bias both channels, and it sounds fine. I'm not worried that it is not at 1.6 v.  I'll take your advice and let it run and check often.
Thanks, Jay