Ref 6SE. Tube dampers

The Ultra sonic Rx are different than the HAL-Os, but I wouldn't recommend them based on your comment..  Hmmm. One of the reasons is you're using Sovtek 6650WEs and I'm using SED winged "C" and KT-88s in the PSs.

I was never fond of the Sovteks which are crystaline and ever so slightly analytical sounding versus the ones I'm using.  The SED 6550 "c" were the originally supplied tube in the REF 10's  predecessor, the Reference 40 Anniversary preamp, but the production quality deteriorated drastically by 2011 and then production ceased, so ARC stopped using them.

Of course, tube rolling has it's own set of challenges, but swapping out the Sovteks for something else will yield a noticeable change in sound. Whether you like it, in your system, is something else again.

Agree with audphile 1 that you just have to experiment. The process is iterative.  I've had good success with vibration control. However, it, power conditioning, and cables are some of the last things I'd focus on.    

@tattooedtrackman best way to find out is to try. When I had ARC preamps I used Herbie’s ultrasonic ss dampers on signal tubes. They didn’t hurt but I don’t recall an improvement either. As long as you have good quality tubes that are low microphonics, I wouldn’t bother with dampers. But… I never tried dampers on power tubes.
I’m also not a fan of vibration control and isolation devices. All I was ever able to achieve with these gadgets in my system was colder and dryer sound with limited dynamics (IsoAcoustics, Herbie’s, Nob Sound springs). Exception was using the springs under the power conditioner
As long as your components are on the solid rack, that’s all that’s needed.
YMMV

@barrysandy ​​@tattooedtrackman 

Thanks for your comments. Anyone else. I have all Audio Research components. My attitude to them has been, they supply tube dampeners, so they probably thought it through… but if there is are lots of folks that have experienced improvement I may be enticed into trying them. 

@barrysandy   I bought 6 Ultra sonic RX for my signal tubes. (6) for my Audio Research REF 6SE. It has a very unnatural high treble in most of my CDs. I will be returning them. 

I own both an ARC Ref40 and a Ref10Phono.  I switched from the stock silicone (?) tube dampers. Am now using HAL-O IIIs on both the 6H30s and 6550s.  The improvement in presence and reduction of very fine veiling surprised me.  I did this in stages and each step was a little better. Just bought some more. I put them  them on the PS first. You'll be happy with this. The PS IS in the signal path!