fender rumble 25 blown?

jumbo7172 · #1 03-11-2013, 10:51 PM

I just got back into playing bass (used to play in high school), i got a Fender Rumble 25 off of craigslist for $40. When i play at low volume (when every one is usually asleep), no problems, but when i crank it past 5 (when i'm alone after everyone has gone to school/work), it gets really staticy. I have the eq middled out (bass, mid, treble all 5), i've messed with the tone and volume on the bass (wasburn xb100 bantam) nothing will stop the static. Is my speaker blown or do i need to adjust something else? I don't want to get another amp since i'm not going to be playing gigs or anything, but when i want to rock, i want to rock, not static. Any ideas?

Sonicfrog · #2 03-11-2013, 11:04 PM

Without hearing it, it's hard to say. Take it to a repair shop and let them evaluate it.

RickenBoogie · #3 03-12-2013, 07:49 AM

Agreed, an amp tech can answer this question, but understand, "rocking out" with a small practice amp can be a big disapointment, as you're very limited on power and available volume.

jumbo7172 · #4 03-12-2013, 07:58 AM

lol, thanks guys. I wasn't trying to rock out as in bringing the house down, just be a little louder than when i'm trying to be quiet as everyone is sleeping. I did some research and it turns out that almost every fender rumble model amp has had complaints of the same thing, one guy had 2, bought one new and one used, both did the exact same thing at the exact same volume point, apparently it's a resistor or something that needs changed. Thanks for the input!!!

5 Wire · #5 03-12-2013, 08:46 AM

Before you take it to a tech, open it up and blow it out with an air compressor.

jumbo7172 · #6 03-12-2013, 04:45 PM

well, i'm not taking it to a tech, i stopped by the closest music store to me (30 miles) today, they don't do repairs but they're a drop off point for another company 30 more miles away, and they said the bench fee for even looking at it is $55 up front. I paid $40 for the amp. I found a forum somewhere (maybe the Fender forum?) where the same thing happened and he changed a resistor or capacitor or something (i'm electronically inclined but i had no idea what they were talking about because they were throwing out numbers like crazy). Here is the fix thread...

Problem turned out to be U6, LM3876. I replaced it and c38 (a 2.2 mfd 50 v) with 10 mfd 50 V and replaced c21 (which IS 10 mfd 50 V.) Problem solved . I can now run the amp at full gain with absolutely no crackling or distortion.

And what are the pots? Someone said he cleaned the pots with contact cleaner and fixed it.

Sorry i'm being such a PITA...

mrmlong · #7 03-13-2013, 10:26 AM

Hi, Bought one of these for $50 last night. Seemed to work well in the store. It looks like you posted the fix I found looking these up. Replacing those components you listed above. If you are inclined, I would find the schematic online and open that baby up and try and fix it yourself. Worst that can happen is you're out $40. Good luck!

FYI. I have been getting bass gear just recently. Before this I purchased an old Peavy Century 120 bass head, it came with a 60's bassman cab for a couple hundred all in. Thing was super cheap for what it is and I love it. Might be a cheap option if you want to get loud.