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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
 
Jim McShane can offer matched, low-noise tubes at a very attractive cost.
mt10425
1,138 posts
 
I'm very happy with the 12ax7 tubes I just got from Jim McShane.
pubul57
3,712 posts
 
The tubes are not special, the way they are measured and matched by Roger is, and they happen to be very good tubes, the Eis that is. That being said, I suspect you would do fine with a set of tubes matched by Jim McShane, or Andy at Vintage Tube Services for NOS. I stick with Roger's tubes because nobody matches better, and he voiced the amp around his tube - keeps tube neurosis from setting in:)
pubul57
3,712 posts
 
Anthony, is Roger only using 1/2 of the tubes? The A half?
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.
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