Fender Rumble 40 upgrades/mods

Discussion in 'Amps and Cabs [BG]' started by J.Wolf, Jan 19, 2019.


  1. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    I know there have been some threads on this, and I did some searching but haven't really gotten the info I'm looking for.

    I picked up a used but minty Rumble 40 from a pawn shop for 100 and change to use for a couple of weekly rehearsals where I dont want to haul out my Berg cab and Demeter head. Its loud, and as light as an empty cardboard box, but obviously the tone is nowhere near as inspiring as the rig I'm used to. I'm wondering if there would be any inexpensive things I could do to make it sound a little better for rehearsal purposes. Not expecting anything earth shattering, but I'd be interested in knowing if anyone has driver replacement recommendations that would be a no brainer, or if anyone has done some bracing reinforcement to the baffle or beefed up the dampening on the inside, or anything that is cheap, easy and effective way to make a Rumble 40 sound considerably better. thanks!
     
  2. G-Dog

    G-Dog What a fun place! Supporting Member

    Feb 12, 2016
  3. rllefebv

    rllefebv

    Oct 17, 2000
    Newberg, Oregon
    I did the mods suggested by @AstroSonic on the first few pages of this thread:

    Fender Rumble v3 40 - First Impressions

    Really improved the overall performance of the amp... I regularly gig it with a few low volume groups. Well worth it!!

    -robert
     
    bobcruz, jallenbass and AstroSonic like this.
  4. You will find a lot of upgrade information for the Rumble 40 V3 on this thread: Fender Rumble v3 40 - First Impressions. To really address the tone issues this combo has you really need to upgrade the driver. Posts 16 and 17 provide information on upgrading the driver with the Eminence S2010. At Basscookers recomendation, I recently tried an MCM 55-2951. This is the least expensive driver I've ever seriously tried: about $14 plus shipping from Newark Electronics. It works far better than I expected, being quite an improvement over the stock driver. The tone is rather similar to the Fender Rumble family tone, but is significantly deeper, more articulate and has relatively smooth mids, though not as much high end as the stock driver. Maximum volume is about the same as the stock driver. The cab must be retuned (port tubes lengthened - see the linked thread). I prefer the tone with the cab tuned to 50-55 Hz. Basscooker makes and sells a cab of close to the same internal volume (about 1 cf), and prefers the tuning lower (40 Hz). You may want to try both. There is a nice review of Basscooker's cab by Tom Bowlus in Bass Gear Magazine (Bass Gear Fall 2015 Page 30{"page":"30","issue_id":278841}). OTOH, the MCM driver falls pretty far short of the S2010, at least to my ear (as it should, costing over 4 times as much). All these driver mods require retuning and the addition of some acoustic damping material (see the linked thread). Good luck!
     
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  5. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    Thank you for this. All things said, would you recommend the cheaper driver or ponying up for the eminence? And it sounds like the port retuning is key, although I didn’t see any specific instructions on that.

    I do like the tilt back leg mod too...
     
  6. I think that the improvement in tone with the MCM driver easily justifies the cost. The S2010 goes deeper and higher, is more articulate and has more upper mids presence. They are really different, equally valid tones. I like them both, but prefer the S2010. YMMV

    Instructions on retuning can be found in the linked thread. Since the earlier 'retuning' post (#'s 16 & 17) Fender slightly decreased the port hole diameter, and later posts do a good job of addressing this (split tube ends).
     
  7. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    The MCM and a couple ports and perhaps some lining sounds like a totally reasonable upgrade for this combo. Do you happen to know the port lengths for the MCM driver off hand? I couldnt find that specifically in the linked thread. And I dont have the software for calculating it, hoping I can learn from your experimenting what is optimal.

    would 2 of these work? not seeing any "split end" options on parts express.

    thanks for your help.
     
  8. Make the ports 2 5/8 inches long. If you use the 2 inch 'Precision' port tubing from PE (or schedule 40 pvc), cut to length and slot the tubing with a hacksaw, about 1 1/2 inches. The slotted end goes in the port hole. Use some aquarium glue to hold them in and to plug the splits. You should be good to go. Save the stock ports in case you want to reverse the mod.
     
  9. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    Perfect, thanks! You just mean cut a little v notch into the port end floating inside the cab, correct? Do you use the adjustable ports or fixed ones cut to length.

    Thanks for adding your expertise here, I’m a bit Ignorant when it comes to these things.
     
  10. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    Gotcha, one 7" tube is enough for the two 2 5/8" lengths. And then just flush mount them to the front of the baffle, glued in place.

    Pardon my continued ignorance, but what does "Use some aquarium glue to hold them in and to plug the splits." what am I having to do to the split ends after I cut the v notches in them. Thanks, I owe you a beer or 3.
     
  11. The slots allow the tubing to be compressed, and fit into the port tube openings on the baffle board. The slots are just that: blade width slots made by a hacksaw. The aquarium glue (silicone glue) is used to glue the port tubes in place, and to plug any openings (potential air leaks) in the port tubes. The only bad questions are the ones that don't get asked, so, if in doubt, ask.
     
  12. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    Oh I see, the port slits in the plastic tubes are so that the diameter can be made a little smaller, and fit in the existing size port holes.

    10-4. Looking forward to getting this up and running!

    So you did this with both ports with the MCM, and not one port blocked as you had described with other drivers?
     

  13. Yes, and with both ports. The S2010 is also with both ports.

    Correct, the slots are to allow the tube diameter to compress a little, so they will fit.
     
    J.Wolf likes this.
  14. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    Awesome, all that stuff ordered! thanks so much

    I have some 2" thick flexible acoustic foam that I lined the bottom of the cab with, with the stock driver. It definitely seemed to eat up some of the mids. I'll have to experiment with the amount of and type of damening in the cab with the MCM and new ports, unless you found a good recipe for that.
     
    AstroSonic likes this.
  15. I did find an amount and arrangement that I liked, but I suggest trying different amounts and locations that produce the tone that you like. You'll find that placement on the back panel has the greatest efect. If you like a little character, you'll likely want 'some' (about 1/3 coverage) on one side, the bottom and the back. If you like 'smooth' you'll want to line all the interior surfaces. For an aggressive tone, leave it empty.
     
    Last edited: Jan 23, 2019
  16. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    Hey guys, just a quick note. I dropped the inexpensive replacement driver in the Rumble 40, added some acoustic foam to the back and bottom of the cab, and added the 2 5/8" port tubes. In quick and dirty listening, it seems much fuller and deeper, I'll be trying it out at a couple rehearsals this week and will report back. Thanks for all your assistance @AstroSonic
     
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  17. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    update, I added the driver, port tubes and some foam on the back and bottom of the cab. It has better low end, but the mids and highs sound pretty out of balance, very subwoofer-y. I wonder if I need to remove some of the foam to help get more mids happening.
     
    AstroSonic likes this.
  18. J.Wolf

    J.Wolf Supporting Member

    Apr 29, 2003
    Asheville, NC
    Contributor- Bass Musician Magazine
    @AstroSonic how much foam did you end up using and on which surfaces, if you recall? thanks
     
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    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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