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12AX7 tubes for Music Reference RM-10

I looking to replace the 12AX7 tubes in RM-10 amp. Looking at the manual it says something about "V1" being grade AB and "V2" being BA. Below is a quote from them:
" Note that V1 is a RAM grade AB (section 1 selected for low noise) and V2 is grade BA (section 2 low noise). It is essential to have a grade A section as the first amplifier to achieve the very low noise of which the RM-10 is capable."
The question is: do I need some type of special 12AX7 tube? Do they have to be matched? Balanced? etc...
Any feedback will be greatly appreciated, thanks in adavance to everyone.
jmcp60
gmuffley
132 posts
 
Both halves of the tube are used. One section is a grounded grid voltage gain section and the other is used as a concertina phase splitter.

Sorry. I meant to say grounded cathode--not grounded grid.
tonykay
856 posts
 
I really like the sound of tubes but after reading this
thread, I think it sounds too complicated to buy used tube
gear. Thanks for stemming my tube neurosis even before it
gets started.
pubul57
3,712 posts
 
TOnykay, you don't have to make the amp, just listen to them, should not be too complicated and you just might find it is well worth the effort to cross the line into tube territory.
hifigeek1
770 posts
 
I have an AVO tube tester in my shop if you need to check some tubes. I've also had very good luck with JJ E83CC/12AX7 tubes if you were looking for a particular brand of tube.
tonykay
856 posts
 
I decided to try tubes in a small way. I boughta tube-driven Stax headphone system. Yes, I like it a lot. So, my
next step will be to buy a McIntosh 275 MkV. If it sounds as good as the Stax, I'll be a convert.
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