Super bassman 300/100t tube thread

Discussion in 'Amps and Cabs [BG]' started by oaklandthumb, Jan 8, 2015.

  1. oaklandthumb

    oaklandthumb Supporting Member

    Nov 12, 2014
    Thought I'd throw in a separate thread for tube rollers. What brands are you using in your fender bass man 300/100t and why?
    Last edited: Jan 9, 2015
  2. 100t: Fender gave me GT Selects. Have had them in since the tech overall and fix(board,tubes, etc. February 2014).

  3. hdracer


    Feb 15, 2009
    Elk River, MN.
    This is already covered in the 300 & 100T threads.
    The 100T uses 6L6's and the 300 uses 6550's.
    Last edited: Jan 8, 2015
  4. oaklandthumb

    oaklandthumb Supporting Member

    Nov 12, 2014
    Wow. Not a bad start. That covers the owners manual, let's talk about different brands, biasing and NOS tubes. Lol.
  5. I put NOS RAYTHEON 5751s in v1 & V2 positions of my Super Bassman.
    It gave the vintage channel a smoother drive when pushed and the actual overdrive in channel 2 a creamier, smoother drive overall.
    I think.
    They've been in for about a year now, so I might change em back to either the original Groove Tubes 12AX7's or try some other 12AX7 's that I've got.
    I'll report what happens.

    The power tubes are still the original Groove Tubes 6550's that came in it when I got it.
    Last edited: Jan 9, 2015
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  6. oaklandthumb

    oaklandthumb Supporting Member

    Nov 12, 2014
    I've heard tung sols in v1 and v2 can have the same effect. The preamp tubes would be my first and probably only mod.
  7. .
    The one and only thing I'm not entirely happy about with my new Super Bassman 300, is the overdriven sound.
    It doesn't have the "beef" I like, even when blended with the clean channel.
    I'd really like a more SVT-like overdrive sound if possible.

    I see that the SVT Classic runs 2 x 12AX7 in it's pre-amp and 1 x 12AX7 + 2x 12AU7 in it's driver tube section.
    The Super Bassman runs 2x12AX7; 1x12AX7 + 1x12AT7 (Power Amp)
    What brand of tubes is in each I don't know at this stage.

    (Forgive me if this is a dumb question, this is my very first all-tube amp.......)

    Will swapping the pre-amp tubes for different ones achieve my goal or is there more to it than this?
    Obviously a Fender amp is never going to sound exactly the same as an Ampeg, but I'd like to get closer to it with the gain up if possible.
    If swapping out the tubes will change the overdrive one, what tubes can you recommend that actually work.

    Thanks in advance

    By the way, I didn't buy an SVT because they were more expensive and considerably heavier!
  8. There's " SVT " settings posted earlier in this thread. Might be useful. I a/b'd mine with a SVT-VR a year ago and got pretty much exactly the same tone. Dunno about overdriving Em tho. I find the vintage channel very easy to geta nice crunch outta. I just use the one 15" and crank it.

    The DRIVER tube in an SVT aren't for OVERDRIVE afaik, they're for driving the power section tubes or sumthin... I know not exactly what!!

    Swapping tubes DOES makea difference in the SB300 as with most amps, is not night n day but it definitely changes the character.
    The 5751s I put in v1 & v2 warmed up the drive.
    Tho far more variation is available with the gain/blend/mid freq/mid level controls.

    The stock tubes are ALL Groove Tubes afaik/iirc etc
  9. Tim1


    Sep 9, 2005
    New Zealand
    This has been covered regularly in the separate SB300 and 100T threads over the past couple of years. Don't suppose it hurts to have a separate thread though, if you want. I can relate that I tube rolled all the tubes when I had my 100T, put Winged Cs in the power section and varied others in the pre - only to find out when I sold the head and put the originals back that I actually preferred the factory tubes!
    As a result I haven't bothered to try anything in my SB300, if it ain't broke don't fix it. I think the general consensus went along with this philosophy as a whole.
    Last edited: May 6, 2015
  10. Yeah I can't imagine it sounding Amy better really. I'm thinking I might just go GT's when the 6550s need replacing.
  11. .
    Man, I've looked and I couldn't find anything about getting SVT overdrive-like tone from a Super Bassman 300.
    I think I'd better go back in and have another look. I'm thinking I didn't look hard enough now!

    Thanks guys.

    Yes, the Vintage channel sounds great. I can get nice clean SVT like tones from it, no problem. I love that side.
    When the gain is up on the Overdrive channel it sounds more like a fuzz than a beefy overdrive to me.

    After reading Rod's post above, maybe it's the power tube side that I need to push in this thing?
    I doubt I'd be able to find a place to try it out at that sort of volume!

    My quest continues.
  12. I getcha. It is an amp that swapping pre amp tubes does make a difference in, so trying a couple of different AX7 tubes can be fruitful
    GG7 and OzzyGreg like this.
  13. .
    A little recording done of swapping 12AX7 tubes in the Overdrive channel of a Super Bassman 300.
    4 bars of one tube, then 4 of the next, etc.

    Fender Super Bassman 300 tube swap experiment

    Interestingly, I did the same experiment a couple of days ago (this is a re-recording of the same thing because I had forgotten to tune the bass before ... doh!) and the Tungsol sounded darker then than the Tube Store tube. I reckon it's the other way around this time.
    It's not that noticeable at 100% gain, but at 50% it really stands out.

    1. OEM tube at 100% gain
    2. Tungsol tube at 100% gain
    3. Tube Store tube at 100% gain
    4. OEM tube at 100% gain
    5. Tungsol tube at 100% gain
    6. Tube Store tube at 100% gain


    7. OEM tube at 50% gain
    8. Tungsol tube at 50% gain
    9. Tube Store tube at 50% gain
    10. OEM tube at 50% gain
    11. Tungsol tube at 50% gain
    12. Tube Store tube at 50% gain
  14. .
    Has anyone experimented with changing the 12AX7 and 12AT7 tubes in the power amp section of the Super Bassman 300?
  15. Addendum to my earlier post regarding the GT Select 6L6 power tubes: These have worked a charm with nary an issue. I have tried to find out more about these ' Selects' with little information found. Anybody know much about these? I figure they must be some sort of premium hand-picked tubes selected by GT. I am curious though.

    Last edited: May 16, 2015
  16. GG7


    Mar 14, 2013
    I use all vintage tubes in my amps.

    GE 6L6GC power tubes and Amperex Bugle Boy 12s in the pre-amp. All from my personal NOS tube collection.

    Sounds AWESOME!

    Likely the best sounding 100t out there. :)

    Th GE 6L6GC was an amazing product. I tried this amp with every vintage brand and every Russian made contemporary brand and the GEs smoked them all by a large margin. The amp sounds like a different amp with the GEs in there.

    As Rod mentioned in his post several months ago, pre-amp tubes don't offer as much of a global difference between high quality NOS vintage brands, although the Amperex in my 100t do give me a bit better bite on the top end with my Rickenbacker and Jazz Basses and all the tone controls seem to have a wider sweep of effect with that brand. And of course quality NOS pre-amp tubes (Amperex, Mullard, RCA, GE, Raytheon etc.) definitely do sound better than Russian ones.

    The materials used in construction back in the golden age of tubes included a lot of now banned materials. Toxic as some of these materials were, they did create a better sounding tube for audio applications. Modern day tube makers simply can't use those exact same materials today, and thus they are not on a level playing field with their NOS ancestors.
    Last edited: May 16, 2015
  17. GG7


    Mar 14, 2013
    Hey Rod!

    Happy to see those 5751s are still doing their good work for ya! :D
    rodl2005 likes this.
  18. Hiya mate. Yep they're still fine. And I'd only consider swapping then out as a means to hear the difference between them and another type. Not because I'm not happy with em in there
    GG7 likes this.
  19. Gig last Sat at a club with a very tight stage.
    Used the Super Bassman & Bassman Pro Neo 115
    not a great pic but you can see the Bassman rig in there back left.
    This weekend I've 2 gigs at a local bar -no PA support for bass, so I'll be using this set up :-
    with my 62AVRI Precision & Alleva-Coppolo EUT5 jazz 5.


    OzzyGreg and GG7 like this.
  20. .
    Probably a dumb question, but here goes anyway:

    Should the (phase inverting) 12AT7 tube glow red like the 12AX7 beside it in the Super Bassman 300?

    The reason I ask is that I just noticed that mine doesn't.
    In fact the 12AT7 barely feels hot to touch after playing. Is this normal?

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