Modify a Fender Rumble to Act as a Amplifier, Cabinet, or Combo

by eric_B

June 5, 2016

original article on TalkBass.com, April 14, 2016

This is a reproduction of an article by eric_B on TalkBass.com on how he modified his Fender Rumble 100 combo (100 watts, 1x12″ speaker) so the combo could be used as

  1. an unpowered speaker, or
  2. an amp head with no speaker, or,
  3. as designed, a combination amp/speaker.

For a while I thought it would be cool if I could use my Fender Rumble V3 100 as a cabinet for an external amp. Following an idea of @AstroSonic, I decided to do this mod and also be able to use the amp to power other speakers. While I was at it, I also upgraded the stock speaker to an Eminence Deltalite II 2512.

The essence is that you disconnect the internal cable from the amp to the speaker and create a loop on the outside of the combo with 2 connectors so you are free to patch.

Here is a set of pictures of the process.

The main parts:

the parts

Eminence Deltalite II 2512:

new speaker

Stock Rumble:

stock Rumble, front
stock Rumble, rear

I already lined the inside last year:

Rumble front, speaker removed

Marking out the place to cut the hole with tape:

lay out the cut-out with tape

First cutting out the covering to double check if the dimensions are correct:

cutting just the Tolex to check the size

Hole cut and screw holes drilled:

the new cut-out

Connections soldered:

the new wiring, viewed from rear
the new wiring, viewed from front

Deltalite 2512 II put in place:new speaker installed

Panel mounted:

jacks installed on plate
close-up of installed jack plate

Jumper cable ready:

the jumper cable
rear view of combo, jumper installed

The internal amp is going out the right connector and is looped back into the cabinet through the left connector which is wired to the speaker.

Final word: it is a pretty straight forward mod, it works fine and looks not too crappy (at least IMO). I just need to put 2 stickers on it to mark the amp and speaker connectors. And be sure not to connect an external amp to the internal one, that probably won't be a good idea!

One thing that I found a bit annoying was that the Neutrik speakon/jack combo connectors are not pure black but have a greenish tint. Though it looks worse on the pictures with the flash light than in real life.

I'll see how I like it on the long run and maybe I'll mod my V3 500 combo as well.

the parts

the parts

the parts

the parts