2. amps-preamps
  3. 1299262706

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
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.
graywulf's avatar
graywulf
10 posts
 
If you know someone with an Avo or a Hickock? problem solved they can check valves to check the sections match for mu and ma ...
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.
Ag insider logo xs@2x
tonykay
1,301 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.
More to discover