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Preamp Tube options? - SWR Grand Prix

Discussion in 'Amps and Cabs [BG]' started by Scotius2001, Jan 9, 2004.

  1. Any of you SWR Grand Prix users (or other tube preamp users for that matter) ever experiment with preamp tubes? I'm wondering if there's a specific 12ax7 version or substitute that will soften up the high end and tighten up the bottom a bit. All input appreciated...
  2. Chuck M

    Chuck M Supporting Member

    May 2, 2000
    San Antonio, Texas
    The JJ is one of the better tubes currently being made. Better still is a USA or European tube from makers like RCA, GE, Mullard, Telefunken or Amperex.

    My favorite tube for the SWR preamps is the Telefunken ECC83.

  3. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    I replaced the original tube with a NOS triple mica 5751. Less hyped highs, tighter lows, more transparent. Less gain though (as with all 5751s) so may not be suitable if your bass has a low output.

  4. Finger Blister

    Finger Blister

    Jul 8, 2003
    After lot's of experimentation, the NOS/JAN
    triple mica plates 5751 sound the sweetest
    in SWR preamps.

    I have found no gain difference between the
    Sylvania 5751 (what I use) and the stock GT 12AX7.
    The preamp peak LED lights the same at the same gain pot positon. They really take that annoying
    "bite" out of the top end while breaking up a
    bit earlier and smoother. Kinda' growls at high
    gain. Nice Low Mid's.

    This is a good tube

    Some Preamp Tube FAQ's and Taste Tests
  5. Tubes are funny - they don't tell jokes but they vary a fair amount from brand to brand and even a surprising amount from individual tube to individual tube.

    There are a lot of very good tubes currently being made for reasonable prices. One can also pay a fortune for a N.O.S. tube - and it may or may not be worth it. With the higher prices they bring, there is also fraud in the N.O.S. market.

    I lucked out and squirreled a bunch away before things got too crazy, and have over 200 NOS for my guitar amps (6L6, 6V6, EL84's, 12a*7's, 6S*7 octals, and 5AR4's 5Y3's, etc. I play electric guitar a lot, but usually without an amp, cranking up only when jammin' with others or occasionally when everyone's out of the house. With the time is split between three really good tube guitar amps, this is probably a life time supply for me.

    The first preamp tube is critical - so you want a real good one there. (This is also the reason I'm a little - cynical I guess - of the bass amps that boast "real tubes"; it's hard to get a really good one.) But they exist, and a tube here should last a good while even under constant use - power tubes are the ones usually pushed too hard.

    I would suggest you get hold of one of the premier suppliers, Lord Valve and NBS (?) come to mind. Stay away from auctions due to the fraud factor. Then - get a bunch and try them out - If you have 1/2 an ear you will be very surprised at the difference.

    All advise given as "in my humble opinion"

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