+ Reply to Thread
Results 1 to 5 of 5

Thread: RCA valves - any good?

  1. #1
    Join Date: Jun 2015

    Location: London/Durham

    Posts: 6,867
    I'm Lawrence.

    Default RCA valves - any good?

    I've just agreed to buy some NOS RCA valves, 2x 6SN7GTB and 3x 12AX7A. The 6SN7s are black plates (not sure if that's what the B stands for). The 12AX7s are short grey plates with the older 50s style thinner writing RCA logo, not the 70s style shorter/fatter style letters. I've read they should be pretty good, but has anyone tried any? I'm not aware of any fakes like Telefunken/Siemens/Tesla, anything I should look for?

    Sent from my NEM-L51 using Tapatalk

  2. #2
    Join Date: Jan 2013

    Location: Birmingham

    Posts: 6,772
    I'm James.

    Default

    I have had a number of NOS RCA valves from 1960's and 70's and they have all been excellent.
    Main system : VPI Scout 1.1 / JMW 9T / 2M Black / Croft 25R+ / Croft 7 / Heco Celan GT 702

    Second System : Goldring Lenco GL75 / AT95EX / Pioneer SX590 / Spendor SP2

  3. #3
    Join Date: Jun 2015

    Location: London/Durham

    Posts: 6,867
    I'm Lawrence.

    Default

    That's good news, I'll be trying them in my pre at the weekend (if the children allow).

  4. #4
    Join Date: Mar 2015

    Location: Berlin

    Posts: 50
    I'm George.

    Default

    Quote Originally Posted by Lawrence001 View Post
    I've just agreed to buy some NOS RCA valves, 2x 6SN7GTB and 3x 12AX7A. The 6SN7s are black plates (not sure if that's what the B stands for). The 12AX7s are short grey plates with the older 50s style thinner writing RCA logo, not the 70s style shorter/fatter style letters. I've read they should be pretty good, but has anyone tried any? I'm not aware of any fakes like Telefunken/Siemens/Tesla, anything I should look for?

    Sent from my NEM-L51 using Tapatalk
    GTA and GTB have same specifications. "B" stands for: "controlled heater warm up time for use in 600mA serial heater strings". The only good RCA valves are early types from 50-ties and early 60-ties. After several thousands hrs. of "tube rolling" I am NOT of the opinion that "black plates" are generally better than "grey plates". RCA black plates sound more colorful, laid back than grey plates (same production years), and slightly edgy -however the slight edginess may disappear after long run-in time. Some valves change their sound characteristic dramatically after a longer run-in time -let's say >200 hrs. By comparison grey plates sound opener, more fluid, less edgy but "greyer" than black plates. What is "better" depends on individual taste and how the valves work in an amp in combination with other valves there. There is NO "better" or "best" valve as such -they all have strong points and shortcomings. Early 12AX7 RCAs sound is close to NOS Telefunken and Brimar valves from this period.

  5. #5
    Join Date: Jun 2015

    Location: London/Durham

    Posts: 6,867
    I'm Lawrence.

    Default

    Thanks for the info, I guess the proof is in the pudding! I'll know more about the 12AX7 by next week but I won't be able to try the bigger bottles til the new year. I don't expect much difference there from my black plate Baldwin branded (for organs) Sylvanias.

    Sent from my NEM-L51 using Tapatalk

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •