Audio Research Ref 3 Opinions

I finally put in a 6550C from ARC to compare it with the 6L6GC tube and the 6550WE tube. First I put about 50 hours of burn time on it.
All I can say is WOW!!! As in 'WOW, why would anybody want to degrade thier Ref 3 with this tube?"
With my present analog setup I usually listen with the volume between 55 and 65, depending on the record. When I really want to crank her up for some electric blues or rock and roll the volume goes up to 75 or even 80 if I want to be wall shaking loud.
With the 6550C in place I first put on Muddy Water's acoustic recording, "Folk Singer". I kept turning up the volume until I was at 90 and yet it sounded like I had furniture blankets over the speakers, talk about veiled. Then I put on Rob Wasserman's "Duet" and went right to the duet with Lou Reed. With the volume at 85 it had no impact, muddy, almost impossible to distinguish the two instruments playing.
I turned off the pre-amp, let the tubes cool down and dropped the original 6L6GC back in. Put the volume at 70, kept the mute on, dropped the needle back on to the Lou Reed track and sat down. Picked up the remote and unmuted the preamp. Back came the visceral bass, the furniture blankets were off the speakers and all the detail and seperation of instruments were back.
Maybe Oneobgyn is mistaken and the bypass caps are necessary in order to improve the sound using the 6550C tube. At this point I would have to hear it in someone elses system before I would chance putting the bypass caps in and trying the 6550C tube again.

I think that the 6550C is not a drop in replacement for the 6L6GC tube. Consequently, you may need to make the other recommended hardware changes in ordr to arrive at an informed conclusion about the relative performance of the tubes in the REF3

See sites below for specs on the two tubes:

http://tdsl.duncanamps.com/show.php?des=6L6GC
http://tdsl.duncanamps.com/show.php?des=6550C

That's very surprising. Although I didn't like the Svetlana 6550c, I wouldn't call the sound veiled to the extent of having speakers blanketed. Something doesn't seem quite right. Although I prefer the Genalex or GEC KT88, the difference was not this drastic.

I completely agree. I am not a big fan of the 6550C either. I talked long and hard with the folks at ARC as to why they went back to this tube. Simply put....more bass. The four by pass caps have clearly smoothed out the upper end in my system. Ethann has heard my system and I am reasonably certain he thought it to be good

Oneobgyn,
Did you try the tube swap before changing the bypass caps? I don't understand why we would have such different results unless Gmorris is correct and you have to do both.
I will have to call Leonard back and see what he says.