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What tube to try in Yorkville Bassmaster 400?

Discussion in 'Amps and Cabs [BG]' started by Zapp, Mar 14, 2006.


  1. Zapp

    Zapp

    Sep 4, 2005
    Gruene Texas
    Friends
    I know many of you are far more skilled in this than I so I need advice. I would like to experiment with a different tube in my Yorkie 400, which is a delicious amp to work with and has made a huge diff in my playing. The issue I would like to work on is that when applying the Tube Overdrive section, the 'sweet spot', if there is one, is very, very narrow, like tiny. The circuit is made to have a pretty broad sweep, but what I find is that it goes from sounding warm & beefy to sounding WAY overdriven in a gnat's hair. I produces through my 2x10+15 cabs a sound that is not at all pleasant when it hits that point, like something badly distorted in an uncontrolled way and I suspect it may be the tube section itself.

    When I leave the OD almost non-existent, I can drive the amp and clean section to the hilt and the tone hangs together nicely.

    Anyway, what's the word? I dunno what the stocker tube is in that thing

    z
     
  2. Hawkeye

    Hawkeye Canuck Amateur

    I know what you mean about the 400, because I tried one this weekend. I also found that it slipped off into uncontrolled tube overdrive very easily and it was hard to find its sweetspot. It gave the notes an undefined and "blurry" sound. A quality tube might really help that preamp. The Yorkie's a nice package at a nice price but a little difficult to dial-in to my liking.

    That being said, it's worthwhile trying different preamp tubes. It made a big difference in my Ampeg SVT 3 Pro . I replaced the mixed bag of Chinese and GT tubes with 4 12AX7 and 1 12AU7 new production Electro Harmonix tubes (hand-picked Russian Sovteks). The head sounded cleaner, the break-up was smoother, the noise floor was lower. It was a noticeable improvement. Anything that sounds cleaner longer and breaks-up a bit more smoothly before edging over into harsh distortion would be a plus.

    I don't know what they put in the Yorkvilles but it's not expensive to "tube roll" and try a few different types. Guys seem to like the JJ Teslas. I put a couple of the JJ's in my ART mic preamp and the improvement was subtle, but there, smoother, quieter. You could spend a bit by trying some NOS Telefunken, Amperex, Mullards etc. but these will likely be pretty expensive.

    http://store.triodestore.com/12axec7057.html

    http://www.tubedepot.com/12ax7.html

    One of the Chinese factories has also reissued a "Mullard" 12AX7 new production that may be worth looking at.
    Have fun.
     
  3. Zapp

    Zapp

    Sep 4, 2005
    Gruene Texas
    HUGE help, Hawkeye. That's the guidance I needed. I think I'll pull the case off today and pull the stocker, snoop a bit.

    it is a very good package but with this one glaring shortcoming. i hope to find the magic :hyper:

    z
     
  4. You may also want to check into lower gain preamp tubes like a a 5751, 12AT7 or 12AU7. They'll obviously lower the tube gain circuit, but may give you the expanded range you're looking for.
     
  5. RevGroove

    RevGroove Commercial User

    Jul 21, 2002
    Burlington ON Canada
    Manager, Account Services: Long & McQuade Ltd. (Burlington); MTD Kingston Basses International Emerging Artist; Bartolini Electronics Emerging Artist
    I replaced the stock Sovtek 12AX7 in my XS800H with a GT ECC83S and never looked back...a colleague tells me he's getting similar results with the XS400H...