Re-tubing a McIntosh power amp

RAM throws out or returns some 90%…. Sounds like the definition of crap shoot…

Also Roger Modjeski ( rip ) built some very advanced testing and grading gear for modern tubes - I have a set of his RAM KT.88 in my RM-9 and his super precise low noise driver ..

RAM tubes

Heavy - your post seemed heavy on buying in bulk and sifting thru the crapshoot of grading tubes. You should get to know Andy and his ears and test gear. I am sure he would enjoy a conversation with you.

Mac in the golden age designed for tube longevity, my 1960 MC240 ran hard for most of it’s life has all original small signal tubes, ditto the 1965 MX110z save one ! tube replacement about 6 years ago.

power output tubes a different story but still relatively long lived in a Mac…. Remember the performance clinics run by factory techs at the dealers ????
Fun

Andy at Vintage tube can help you and rather than fireworks Crap shoot he will get you great tubes, graded and matched… for your amp