ARC Ref 3: Tung-Sol 6550 in power supply?

The best 6H30 tube is the hard to find 6H30 DR. My Modwright 36.5 also takes 6H30 signal tubes. If you can find the true DR tubes that make a pretty significant improvement.

BTW - oneobgyn is a huge help to people.

I have a pair of NOS TungSol 6550 Black Plates (solid) from the early 50s - I will try them and will report back. I'm aslo burning in a quartet of NOS 6H30DR tubes.

Gentlemen, rather than waxing poetic in terms of 'better' and best', it may be useful to describe what makes us prefer a particular 6550 or 6H30 iteration over an other one. As for Tungsol 6550 on Ref 3, I much prefer the SED 6550C supplied by Arc because of its perceivable (by me) linearity and minimal bloom across the spectrum. If there existed a tube that is even more nimble, linear, extended, tight in the bass, and less bloomy than the Winged C 6550C, I may consider it. Anything warmer, I will instead. . . cheerily ignore. I have also tried a set of 5 6H30DRs in the Ref 3, and I could not tell if they made an audible difference.

Guido

it seems to me that you, as I, have experimented and have found no appreciable gain with tube rolling on the Ref3. I still maintain my stance on that as you and I have found changes that involve tube bloom etc. Again, differences will be heard, BUT everyone must ask of themselves "did I hear something better or did I just hear something different"

Strange that no one is offering comments on swapping a KT88 for the 6550C

I did try the Tung-So in my Ref 3 and went back to the SED 6550C rather quickly. In power amps the Tungs were better but the Ref 3 seems voiced for the SED 6550C. I also found the Tung more noisy. I am using a Tube Store SED, but the best so far has been the ARC provided tube!!