Which 6146 tubes for a 60's SVT Blueline?

Discussion in 'Amps and Cabs [BG]' started by dash34, Aug 22, 2018.

  1. dash34


    Jan 20, 2009
    My tech claims my 6146's are finally done. Not surprising as the tubes were last replaced in the 70's. However, acquiring replacements is an issue as there are three different types of 6146's available - 6146 A, 6146 B, and 6146 W. I have read different articles claiming alternately that the A's or the B's are the correct ones. Does anyone have the skinny on this? Or does it depend on the serial number of the amp?
  2. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    A's are not correct at all. They originally came with 6146B's, but 6146W's are often substituted because they are a military grade 6146B. My 69 SVT has W's in it currently. But definitely NOT A's. Very bad idea, the A's. B's or W's only.
  3. cerrem


    Apr 4, 2006
    San Diego
    I would also concur with JimmyM about the 6146 variants...
    Keep in mind that most of the articles you find on-line pertain to RF applications which is all about tuning the circuit at specific frequencies...
    For the SVT you would use the 6146B and the 6146W ...the main reason is due to plate dissipation...
    Many of the later built 6146W tubes were actually 6146B tubes more ruggedized....such as more mica in the spacers and a thicker glass....
    Those 6146W tubes I would recommend are the Sylvania, TUNGSOL and the GE JAN ones...
    DO NOT convert the head to 6550....it will be a dog and put out low power due to the lower screen voltage available in those early models..
    I happen to have several matched NOS quartets of GE 6146W JAN tubes....these are factory matched ....
    If interested message me...
    JimmyM and Jim C like this.
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