ARC REF 6 upgraded by ARC.

@cleeds I guess the 1,000,000+ Fellow Americans that died are just another hoax to him.  When you are lucky enough that your distant relatives managed to get to America so YOU could be born here and say ignorant stuff like that, I guess he missed the line where brains were handed out.

No one HE knew managed to die, so I guess it all never happened.

How fortunate.  The NEXT one will be worse, of course, but unless HE dies, it will not have happened either.  Were his distant relatives here for the 1918 Spanish Flu when 600,000+ Americans died?  Naw, another hoax, I guess.

As we say in the south, "Why, bless your heart!"

Someone mentioned doing this yourself.

Back in the "very old" days, ARC sent out kits to us dealers for upgrading the SP-3 to an SP-3A1.  I did about a dozen for my customers back then.  I forget exactly--it was 48 years ago--but as I remember it was about 10 parts.  HOWEVER, upgrading to the D-76A amp was a COMPLETE change inside the case, so it had to be done at the factory.

I would guess your Ref6 upgrade needs the factory people to go through it and make sure everything is right.  It is expensive, but if you love the new sound, go for it.  As the saying goes, “The bitterness of poor quality remains long after the sweetness of low price is forgotten.” ― Benjamin Franklin

Cheers!