Best modern 6550 tube for ARC per-amp

@tubegb

So, now one of your proposed strategies is to place a tube of questionable history, possibly fake, and with untold/undetermined hours of use in your $15,000 preamp?

lol...

well i guess we have all scratched the scab off of a healing booboo, make a bloody mess ... sometimes in spite of what is good for us... path to nirvana is often over some rough terrain in parts

Indeed, far from perfect. I could recount/regale endless stories of questionable moves/decisions made over the 40 years in this "hobby"...

In any single-ended product the quality of the regulator is certainly quite audible! And while the signal does not go through it, the regulator has to have good linearity just like any power amplifier- and that is exactly what it is. So you want to use a good tube. JJ makes a blue glass variety that is quite nice and not crazy money, also reliable.

good input ralph

the ref 6 is a true balanced model though... but probably what you say still applies...

question -- would a 6550 that sounds good in an audio amplification role be necessarily a ’good sounding’ one when asked to do voltage regulation, or are certain other characteristics of the tube more important when acting as a regulator?

@mmbl622 
I find in interesting how so many can so passionately claim there is no way a voltage regulator tube in the PS can play a part in SQ.  Well I was a skeptic until yesterday.  I recently got an ARC REF 5SE and wasn't as impressed as I expected moving from the LS27.  My 6550 had about 1800 hours and I swapped a new EH 6550 and was blown away.  I took the time to swap the old one back and then to the new one again and there was no question.  Everything opened up with such better detail.  All the instruments and voices popped and were so precise.  I had read in some thread here a while ago how important these 6550s are in ARC preamps.  I am going to stock up on the Sovtek as that is what ARC ships their units with so that's good enough for me.