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Fender Vibrolux Reverb problem


GPNfan

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I have a 2012 Fender Vibrolux that has recently developed a problem with the Reverb and need some help trying to figure out what is wrong. Tuesday I fired my Vibrolux for the first time since February of March just to see how my new Joyo California Sound pedal worked with it and had a loud hum. At first I thought I just didn't have a cord plugged in good or I had hit the volume knob and cut the amp up. Well it wasn't either so I grabbed my noise suppressor and plugged it up with no luck there. Next I thought maybe it's the amp picking up something from the tv since the back of the amp is near the tv and it wasn't that either. I can't remember if I turned the Reverb knob or hit the Reverb foot switch but I did discover that the Reverb was the problem. If you cut the Reverb off the hum goes away and if you turn the Reverb knob all the way down the hum goes away. If you turn the Reverb knob from 0-3 you have full volume and some hum but after you pass 3 the volume drops and the hum gets very loud. The weird thing is if you pick the amp up the hum almost goes away but is still louder than the hum of a single coil. I only discovered this when I picked the amp up to turn it away from the tv. The only thing that's happened to the amp besides getting bumped into when walking past it is the bottom got a little wet. In May water got into my house after a storm came through. I don't think the amp should have gotten wet enough to hurt it because I had a couple of guitars in cases and one just sitting out as not water got into either case and no damage was done to the guitar that was just sitting out. Also my Fender amp cover wasn't wet at all. So if anybody has a clue as to what the problem may be please help me out. Thanks for any help you can give me.

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I have a 2012 Fender Vibrolux that has recently developed a problem with the Reverb and need some help trying to figure out what is wrong. Tuesday I fired my Vibrolux for the first time since February of March just to see how my new Joyo California Sound pedal worked with it and had a loud hum. At first I thought I just didn't have a cord plugged in good or I had hit the volume knob and cut the amp up. Well it wasn't either so I grabbed my noise suppressor and plugged it up with no luck there. Next I thought maybe it's the amp picking up something from the tv since the back of the amp is near the tv and it wasn't that either. I can't remember if I turned the Reverb knob or hit the Reverb foot switch but I did discover that the Reverb was the problem. If you cut the Reverb off the hum goes away and if you turn the Reverb knob all the way down the hum goes away. If you turn the Reverb knob from 0-3 you have full volume and some hum but after you pass 3 the volume drops and the hum gets very loud. The weird thing is if you pick the amp up the hum almost goes away but is still louder than the hum of a single coil. I only discovered this when I picked the amp up to turn it away from the tv. The only thing that's happened to the amp besides getting bumped into when walking past it is the bottom got a little wet. In May water got into my house after a storm came through. I don't think the amp should have gotten wet enough to hurt it because I had a couple of guitars in cases and one just sitting out as not water got into either case and no damage was done to the guitar that was just sitting out. Also my Fender amp cover wasn't wet at all. So if anybody has a clue as to what the problem may be please help me out. Thanks for any help you can give me.

 

Maybe the reverb tank in the bottom of the amp cabinet got wet? Try unplugging the reverb tank and see if the hum goes away. Or try wiggling the RCA connections around to make sure they are making good contact. Sounds like it might be a little complicated if it's not just the reverb tank or it's connections. But I"d try that and see what happens. [thumbup]

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I'd be looking in the reverb bag, in fact, if it sat it water I'd be gettin a new tank for it.

 

My recent Vibrolux purchase had exactly the wrong tube in the reverb hole. It sounded fine as it was, I don't know too much difference between an AX and an AT, but I put the right one in anyway. I've had dodgy tubes in reverb before and it was never good, so have a look at that also.

 

rct

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Thanks for the help so far. I will say the Reverb tank was my first thought with the tubes being second. One thing about the tank is that when I moved the amp while it was on you could hear the springs in the tank rattle when I say the amp down. One thing I forgot to mention was that the Reverb is almost always on. I rarely ever cut the Reverb off and the foot switch is always on the top of the amp. I've never completely unwound the cord to the foot switch. As for the amp getting wet it was never submerged in water but rather sat on a wet carpet. In fact the two this in cases were on a wetter part of the floor and as I mention neither case had any water damage. I get that the dampness could have done the damage but would it really do that much damage? One last thing I can think of at the moment is that the amp is always covered with the amp cover when not in use so dust shouldn't be an issue. Thank for the help.

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  • 2 weeks later...

So when I finally had time to check some of the things that you guys suggested I had something else happen. I cut the amp on and it took a couple of minutes to get the Reverb to do anything.I was hitting the foot switch and it was doing nothing. Then when the Reverb came on Still humming I checked the RCA wires and that had no affect on the hum at all. After I sat the amp down after having it tilted toward the Reverb tank rattled but instead of the normal noise you hear you heard a static that over powered the tank noise.

The main question I have is should I pull the Reverb tube or will the amp be fine just leaving the Reverb off? Is there a way to check the tube besides using a tube tester? And how do I check the Reverb tank?

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So when I finally had time to check some of the things that you guys suggested I had something else happen. I cut the amp on and it took a couple of minutes to get the Reverb to do anything.I was hitting the foot switch and it was doing nothing. Then when the Reverb came on Still humming I checked the RCA wires and that had no affect on the hum at all. After I sat the amp down after having it tilted toward the Reverb tank rattled but instead of the normal noise you hear you heard a static that over powered the tank noise.

The main question I have is should I pull the Reverb tube or will the amp be fine just leaving the Reverb off? Is there a way to check the tube besides using a tube tester? And how do I check the Reverb tank?

 

When I am checking out one of the 12ax7 or 12at7 tubes in one of my amps, I typically will pull the questionable tube and put a replacement in to see if that solves it. There is no bias adjustment required on those tubes so it is straight forward. I would not leave the spot empty. Unless you have access to a tube tester already, a tube tester is quite expensive but a replacement tube is about ten dollars. I would just swap tubes.

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Guest Farnsbarns

This is sounding to me like the coaxial RCA lead for reverb out and in is at fault. Could be the send and return valves or the tank but fact that moving the amp about is affecting it makes me think the cable is at fault. I had this with my supersonic, when it was new, a new cable sorted it. Then again, if it was wet the tank seems a likely culprit. Cables are the cheapest and have other uses, then valves and they also have other uses, then the tank and that would just be surplus if you found it wasn't that. I'd work in that order for those reasons (assuming little or no diagnostic tools or know how)

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