20 Most Recent Fender Rumble 100 Bass Guitar Amplifier Questions & Answers

A common reason for 'distortion' with all bass amps can be either that the screws holding the speaker unit to the cabinet have worked loose or that there has been a build up of dust particles in the corrugations around the edge of the speaker cone, which rattle especially on the lower notes.
The solution is simple - remove the front grille and check the screws are tight. Use a vacuum cleaner to remove dust from the rim of the speaker cone.

Does it still happen with the gain turned down a bit? Have you tried different cords? It may just be the pickups interfering with the amp

Before changing the speaker, check for debris or other things in the cabinet or grill that MIGHT be rattling..

Also, plug in an external speaker to the ext jack and see if it is clean.

There is an inconsistency in your text. You indicate that cables were swapped and problem still existed...
You said:... "i have tried using it on a different amp and still fine".

If you tried it on a different amp and it was still fine then the guitar is probably OK.

THEN your amplifier is in question as the root of your problem.

What is the amp you have? The guitar is the CB-42, but what amp do you have?

MANY intermittent problems with amplifiers are often with the input jack itself. These jacks are easily broken by tripping over a cable plugged into them.

replace. hopefully its a simple plug and play so you just have to plug in the new input.

Will send schematic

I just fixed my bass amp with a similar problem last week: the problem is related to a loose connection on the PCB board (likely).
A bass amp is a rough place for circuitry: the low rumble and power shake a bass amp more than a guitar amp.
In my case, the power transistors needed to be re-soldered and then the grounding bolts and screws needed to be removed and cleaned because the connection was bad. Remember that when two different metals needed for an electric connection are toughing, there is the likelyhood that corrosion WILL happen.
My bass amp did basically the same thing yours did: sounded good at low volumes, but at higher volumes it would act up.
In short, there is nothing you can do (unless you are a repair person): you need to take it to a local music shop and have a tech fix the intermittant contact problem: someone who knows what they are doing should only take an hour at most.

Hope that helps!
-mike

Verify that your CD equipment is powered from the same receptacle. Check the audio cables as boken shield would be a common cause of hum.

VERY common problem... this is why you ALWAYS loop your cable through the handle. One trip over a guitar cable and the yank sideways destroys the jack... AND the jacks are really weak and poor to start with... Take the thing in for repair, or if you are electronically adept replace the jack yourself. MOST of these have the jack soldered to a circuit board and one often has to remove all the front knobs and the nuts holding the volume controls and move the bord back to remove and replace the jack...

Try this link:http://www.fender.com/support/amplifier_schematics.php If your amp isn't listed contact them and they will send you one.

Our human perception of loudness can be way off. You should get a soundmeter and compare. There are some pretty good ones on eBay new for about $140.

Adding speakers may NOT increase the sound much as the power will then be split between the speakers.

First check speaker and speaker wire.

I just removed the head from a rumble 100 I just got yesterday, you have to remove the 4 screws in the top, then the four that hold the handle on the top, and also the two from the sides. Slide the head out the back, but be careful of the wires attached so you don't rip them out (they are sort of short). Also be careful not to touch any electronic parts on the boards, some are extremely high voltage and can electrocute you (even when the amp has been unplugged)

Hello,
To answer your question: YES and NO this is an easy fix.
Yes if you have the tools and knowhow, and NO if you don't know what you are doing.

There are high voltages in an amplifier that can persist even when the power is off (I have a Laney amplifier that will remain at several hundred volts for days after the power is off). There could be enough voltage stored in the capacitors to give a fatal shock.

At a minimum, you need a voltmeter, soldering iron, some 64/40 rosin-core solder, the replacement part.
Such a fix is pretty cheap for a repair shop. This is about as easy a fix a repairman can have, but thats because they know how to get in and do it without getting hurt.
I work on amplifiers and build them, and always take each time I reach into an amplifier that has had upto several hundred volts seriously. I know that I would charge no more than 1/2-3/4 hour shop time for such a fix plus parts (or about 30-ish bucks). I would think a local shop can do this for you at no more than 30-45 dollars per hour shop rate. Any competant repairperson should only take 15 minutes or so after the amp is out of the case: more time is spent getting it in and out and being safe about it with this type of repair.

Hop that helps!
-mike

Here is the schematic:http://www.fender.com/support/amp_schematics/pdfs/Rumble_Bass_Schematic_-B21.pdf Check the tubes to see if one is loose in its socket. Do not attempt to repair this yourself unless you have amplifier repair experience as it is easy to get a bad or life threatening shock without the correct test gear and troubleshooting procedures.I hope this helps.

you can buy a new quarter inch jack at radio shack. These have a tendency to go bad due to all the wear put on them. Buy a new on and sotter the connections on. I think you will find your problem.