Audio Research CD7's 6H30 tube rolling


The CD7 uses 6H30 tubes - 3 for power supply and 4 for the output stage.

Presently there are only new 6H30 tubes from Sovtek and Electro-Harmonix and NOS 6H30-DR tubes from the Russian military from around 20 years ago.

Some people have commented that the NOS tubes are sweeter sounding and have more "air" extension with their CJ or ARCref3 preamp equipment and others have commented that the latest new tubes (around 2005+?) sound so good that there isn't any difference anymore in sound.

Has anyone done tube rolling for this CD machine with the NOS tubes? And with what results? Would it be better to change the 3 power tubes or the 4 output tubes? Or all 7 tubes perhaps?

Thanks in advance for any comments!
flkin
I had both Audio Research and Conrad-Johnson power amps with new production 6H30-EB drivers a few years ago. I replaced them with pricey NOS -DR versions and I couldn't tell much difference. Maybe it might make a difference in a CD player, but based on my experience, I doubt it would be worth the difference in price.
I went ahead and ordered 4 NOS tubes for the output stage. The seller was kind enough to confirm that I could return them in mint condition less a restocking fee should I find that there is no change in sound.

The CD7 (brand new) started by sounding extremely detailed but bright. Perhaps bright isn't the correct term - more like forward. To the extent that it was tiring to listen to for long periods. I attributed some of this sound to the tubes and thus the search of a solution.

But after burining in for 150 hours or so, it's much better. The detail remains but the sound is now rounder and sweeter. The treble performance of the standard new tubes is now outstanding and I'm wondering if the NOS can do any better. It's already pretty incredible as it is now.
You mean to say that your cd player only has 150 hours on it? That's early to tube roll. This player would need about 400 hours of playing before you can judge the sound. To try to alter the sound now seems like a bad idea to me.
Hello Flkin , after 2 years of use , I decided to rollout the current 6H30P-EB tubes by the DR version , I swapped all the 7 tubes . Result is that the NOS tubes sound better
in every aspect the AR is famous for . But I also have changed the clock with its own powersupply ) Tentlabs , a Dutch brand ).This makes the CD7 even a more better player ,bigger soundstage and more air .I think that in my situation the clock is responsible for 60 % and the tubes for 40 % for the better sound.
Greetings from the Netherlands Hans