Replacing valves in TLA 5051

Discussion in 'General Discussion' started by Gem, Mar 26, 2012.

  1. Gem

    Gem Active Member

    Joined:
    Mar 22, 2012
    Location:
    Glastonbury,Somerset.
    Hi, my first post here!
    I have just got a TLA 5051, and after replacing cheap Chinese 12ax7's (ecc83) for electro harmonix (Russian) ones, I am curious to know whether I can replace with ecc88's, as I hear these are nicer, and i have some amperex ones from holland, but do they have a different grounding pin config, and will this be bad for the 5051? The reason I ask, is although I have read up a lot recently about the difference between the valves, when I changed the valve (ecc83) from my Rode K2, to the advised, 6922 (ecc88) there wasn't a problem.. Yet there seems to be an advisory against using ecc88's instead of ecc83's .. Many thanks, for any light shed upon this.
     
  2. Boswell

    Boswell Moderator Distinguished Member

    Joined:
    Apr 19, 2006
    Location:
    UK
    Home Page:
    They are not a direct replacement as (at the very least) the heaters are wired differently. The ECC83s have a 12.6V @ .15A heater wired between pins 4 and 5, but centre-tapped at pin 9, so by wiring 4 and 5 together you can supply the heater with 6.3V @ .3A between this point and pin 9. The E88CC has a 6.3V @ .3A heater on pins 4 and 5 with pin 9 being a grounded screen.

    I don't know how you had an ECC83 working in a Rode K2 as it's wired for the 6922/ECC88/E88CC. Here's a recent thread on that subject.
     
  3. Gem

    Gem Active Member

    Joined:
    Mar 22, 2012
    Location:
    Glastonbury,Somerset.
    Thanks, yes I saw that thread, but the K2 came with that valve (Mazda ecc83) in it! From new... So when I ordered a different valve, the 6922 came as a replacement.. Both work! Bizarre..
     

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