Marshall VBA 400 valves?

Discussion in 'Amps and Cabs [BG]' started by jokerdean, Oct 9, 2011.

  1. jokerdean


    Apr 6, 2008
    Hi, I got a nice VBA400 with some nice 6550c svetlana valves, sounds awesome but can I take it any further? preamps havent been touched. Thanks in advance
  2. Clammy


    Nov 3, 2008
    Ottawa, Canada
    Endorsing Artist: Neal Moser Guitars, DR Strings
    I just got one too. Liking the Svets in there. I swapped in some NOS RCA and Mullard 12ax7s, and replaced the stock (whatever it was) 12au7 with a NOS Sylvania. The amp already sounded really good, but the tube change definitely woke things up. It sounds like thunder! :D

    tomich likes this.
  3. Yep a pre amp tube replacement on the VBA can really make this amp a fat snarling beast (even more so).

    FYI the stock 12ax/au7's are Sovtek rebranded with Marshall.

    I too replaced mine with NOS Sylvania 12ax7(Baldwin organ) for v1-v3 and a NOS RCA Blackplate for the 12au7 in v4.

    I just love it - tubey, growly goodness.

    My Power tubes are still the stock Marshall/Sovteks as Ifeel they make less of a difference to tone, however when they die Ill probably put some winged C's in.

    Either way have some fun playing around with tube pres. It can get expensive if you follow up every piece of advice (depending on what sound you are after), however I found that most of the online tube retailers to be quite straight forwards and clear about tube suggestions.


  4. tomich


    Sep 8, 2006
    I found changing the pre-amp tubes makes a MASSIVE difference in this amp. The Sovteks that came with it were not the best - almost anything I tried was better!

    Particularly great was the 7025/E83CC HIGHGRADE TAD (RT030). It really improved the mids and makes the bass tone more 3D.
  5. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    If the valves are dying, replacing them with working right ones will make a lot of difference. The difference between working right valves is very small.
    agedhorse likes this.