ARC Select Worth Price?

I am not a tube roller in general, at least not for Audio Research equipment. I know Audio Research has put tremendous design effort into achieving the exact sound you get with the stock tubes and changing tubes changes the sound. I bought Audio Research for the exact sound I get.

 For more generic sounding equipment or less expensive I would consider tube rolling. And have in my PrimaLuna for example and my Woo Head amps. 

Having said all of that. One of my audiogon friends tried and liked a NOS General Electric 6550... which goes in the power supply circuit on the ARC Ref preamp, phono stages and DAC. So, just for fun I tried one. There was not a huge difference... but it was just a tad warmer more tubey. Not a lot... subtle. So I kept it and put one in my DAC. But as I said, not a huge change. If I had really trebly / hot speakers it would probably make a bigger difference. 

Upscale website gives this further detail:

We deal with some fairly picky customers that want to make sure that their expensive ARC preamps, phono stages, and amps are as close to perfection as possible. For that customer we have 6H30’s in a grade called “ARC Select”.

This grade has four distinguishing characteristics:

1. The transconductance measurements will be as high as possible, resulting in a tube with the longest life.
2. Internal balance between the two triodes of the tube will be as tight as possible, within 10% (triode balance on a 6H30 can easily vary by 50%)
3. The microphony will be the absolute lowest possible, tested in a moving coil phonostage test circuit with 60dB of gain.
4. The noise will be the absolute lowest possible while being pushed in the same moving coil phonostage test circuit.
   
    

My prototype K&K Audio phono pre and Line Stage use a total of six 6H30s. These tubes are configured as diff. pairs with current source tails and CT transformer loads. Since the Lundahl LL1689 transformers will tolerate only a small amount of DC current the 6N30 tubes need to be matched for plate current at the OP. None of the tube dealers will do this and unfortunately my friend Kevin Carter of K&K has passed away. So I bought four ARC select tubes from Upscale and three of them met my specs. So I ordered twelve more with the same yield. As a result I have twelve tubes I can use and four that need a new home.