Audio Research Ref 3 Opinions

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.

No....I took my unit to an authorized ARC repair man here in the Bay Area

ARC shipped both the replacement tube as well as the 4 bypass caps to him. He did the install in less than 1/2 hour. All I did was pay the $60 for the new tube. Both the tube and the caps are rolling line changes and not upgrades to the unit.