New Peavey Minimega and Headliner 410 hum

[Blender02]

Question:

Just purchased a Peavey minimega and headliner 410 cabinet. Love they way is sounds but the problem is the hum. I have a terrible hum when the Amp is plugged in and it's really bad once I plug my sansamp into it.

I unplugged the sansamp and the bass (Fender P bass passive ) and the amp stills hums so I assume it's a grounding issue.

So, I purchased a Humno from Morley and it didn't change a thing. Any suggestions? It seems to be a grounding issue because it stops once I play the bass and touch the strings.
And, like mentioned before, the hum is loud when the sansamp is plugged into the input jack but it sounds much better plugged into the front than the fx loop in the back.

Any help or suggestions would be much appreciated.

 

[KevInDaBassment]

I unplugged the sansamp and the bass (Fender P bass passive ) and the amp stills hums so I assume it's a grounding issue.

Are you leaving the instrument cable plugged in when you're at this phase of testing?

Might need to check your outlet or see what else on the electrical circuit could be causing the noise (Battery Backup Surge Protectors, certain PC equipment, etc.). I'm no electrician, but that could be a wiring issue if that disappears trying outlets in different parts of the house. It could be an issue with the amp itself, I've seen some that would generate noticeable noise with no instrument plugged in at all.

I'm sure folks wiser than I will swing by soon, but I had a similar problem and it turned out to be a computer Battery Backup I had plugged in that caused the noise. YMMV.

 

[agedhorse]

If the amp is quiet when you touch the strings, it's almost certainly not the amp. A bass with a missing bonding connection between the bridge and the output jack's sleeve terminal will result in exactly these symptoms.

What happens when you unplug everything from the amp's input, no pedals, nothing but the amp powered up? Is it quiet?

 

[Blender02]

If the amp is quiet when you touch the strings, it's almost certainly not the amp. A bass with a missing bonding connection between the bridge and the output jack's sleeve terminal will result in exactly these symptoms.

What happens when you unplug everything from the amp's input, no pedals, nothing but the amp powered up? Is it quiet?

No. It still hums.

 

[eniac]

Is the amp new or used?

 

[Blender02]

new

 

[agedhorse]

Ask the dealer for assistance.

If it's quiet when you touch the strings, that still indicates a problem with the bass.

 

[eniac]

new

I was afraid of that...

1) Disconnect the Humno and set the Sansamp aside for the moment. Plug an instrument cable straight into the amp but don't connect the other end. According to the story so far, you should hear hum. Do you?

2) Now, at the (disconnected) instrument end of the cable, touch the metal shell. Does the hum change?

3) Next, touch the metal shell at the (connected) amp end of the cable. Does the hum change?

 

[Blender02]

I was afraid of that...

1) Disconnect the Humno and set the Sansamp aside for the moment. Plug an instrument cable straight into the amp but don't connect the other end. According to the story so far, you should hear hum. Do you?

2) Now, at the (disconnected) instrument end of the cable, touch the metal shell. Does the hum change?

3) Next, touch the metal shell at the (connected) amp end of the cable. Does the hum change?

1). Yes… As soon as I plug a cord in, it starts to hum, but it doesn't hum when there's no cord into the input Jack. And as you ask cord connected to no instrument.

2). Yes… I can stop the home by touching the metal input jack of the disconnected side.

3). No… Touching the metal shell At the connected input Jack doesn't do anything.

But, after i connected the Morley Humno, touching the connected metal input, jack stopped the hum, unlike when the Humno was not connected

 

[Pulverizor]

Do you have another instrument cable to repeat test one? Or even a patch cable?

 

[Blender02]

Do you have another instrument cable to repeat test one? Or even a patch cable?

I tried it with another cable and it does the exact same thing… I was actually wrong though… With the Humno or without it, touching either the input jack or the disconnected Jack metal sleeve will stop the humming

 

[Thundar]

I bought an early MiniMega years ago and it had a "whine" that changed when the display changed colors or when I set it to a different color. (For those of you unfamiliar, you can choose the display color or you can set it to rotate thru all the colors). Also the fan was loud, so all that combined was unacceptable, even though I am used to Peavey heads having loud fans, so I sent it back.
I bought the MiniMax and even though on paper it has less power, I felt like it actually had more output than the Mega. The MiniMax also has a loud-ish fan, but it was not as bad, and at a gig or band practice, it was not noticeable and I didnt have to deal all the "extras" that bugged me about the MiniMega.

 

[eniac]

At this point I'd take Plucky's advice and suspect the AC power. That rig is a giant pain in the neck to move, so can you run a long (3-prong, obviously) extension cord to an outlet in a different part of the house and try again?

You could also "test" (quotes intentional) the outlet with an outlet "tester", but be aware that those things don't uncover all possible problems. They will show some, though.

 

[agedhorse]

1). Yes… As soon as I plug a cord in, it starts to hum, but it doesn't hum when there's no cord into the input Jack. And as you ask cord connected to no instrument.

2). Yes… I can stop the home by touching the metal input jack of the disconnected side.

3). No… Touching the metal shell At the connected input Jack doesn't do anything.

But, after i connected the Morley Humno, touching the connected metal input, jack stopped the hum, unlike when the Humno was not connected

Ok, you said earlier that it hummed with no cable plugged in, but now you say that there's no hum... which is it?

If it doesn't hum with no cable plugged into the input, it's almost certainly not the amp, but more likely the bass or that the cable is not an instrument cable but a speaker cable.

Accuracy is critical in troubleshooting.

 

[Blender02]

Ok, you said earlier that it hummed with no cable plugged in, but now you say that there's no hum... which is it?

If it doesn't hum with no cable plugged into the input, it's almost certainly not the amp, but more likely the bass or that the cable is not an instrument cable but a speaker cable.

Accuracy is critical in troubleshooting.

Ok. so I double checked everything last night.

I moved the amp and head to several outlets in my apartment last night....I used three different chords...2 20ft and 1 10 ft. All the results were the same....

Amp/head plugged in...no hum Amp/Head with cable plugged in to front input jack with no instrument hummed loudly. Touching either of the two jack jack sleeve would stop the hum but disconnected one seems to stop it much easier.

Humno pugged in or no Humno didn't change a thing.

When passive P bass is plugged in, hum stops when the strings are pressed down. If not, hums super loud.

Plugging in my sansamp made it much worse....Especially if plugged into the front input jack. Still mummed if ran through the fx loop but not quite as bad. The tone of the bass being played with sansamp sounds so much better through the front input jack instead of the fx return but the hum when not playing is crazy.

Needless to say, I'm an idiot with this stuff and I APPRECIATE everyone's help greatly.

 

[CascadeBass]

Thank you for clarifying. I was also confused because Agedhorse asked you what it does with NO cables attached and you gave conflicting information.

Anyway, I would say go buy a different cable just to cross that off the list at least.

Agedhorse can take it from here, lol.

 

[agedhorse]

Thank you for clarifying. I was also confused because Agedhorse asked you what it does with NO cables attached and you gave conflicting information.

Anyway, I would say go buy a different cable just to cross that off the list at least.

Agedhorse can take it from here, lol.

It should have increased hum level with a cable plugged in but unterminated at the other end.

Also, be sure you have a shielded INSTRUMENT cable and not an unshielded speaker cable. This is essential.

Also, try your amp with a known good bass, I still think you have a bass problem, and maybe more than that.

 

[eniac]

When passive P bass is plugged in, hum stops when the strings are pressed down. If not, hums super loud.

This suggests Agedhorse has nailed it. Pull the bridge and verify the ground wire is in good solid contact with the underside. And that there's no goo or whatever on the wire going to the cavity and on the bottom of the bridge itself. If it's a 2-piece bridge, make sure the halves are tightly fastened together. While the strings are off, pull the pickguard and make sure the bridge ground wire is properly soldered in place so it has a path to the output jack's sleeve terminal. Wouldn't hurt to do a general sanity check with an ohmmeter, either, to make sure everything's connected to where it should be.

Just had a thought... are you using tapewounds?

 

[Blender02]

This suggests Agedhorse has nailed it. Pull the bridge and verify the ground wire is in good solid contact with the underside. And that there's no goo or whatever on the wire going to the cavity and on the bottom of the bridge itself. If it's a 2-piece bridge, make sure the halves are tightly fastened together. While the strings are off, pull the pickguard and make sure the bridge ground wire is properly soldered in place so it has a path to the output jack's sleeve terminal. Wouldn't hurt to do a general sanity check with an ohmmeter, either, to make sure everything's connected to where it should be.

Just had a thought... are you using tapewounds?

No. Its a 2007 mike dirnt fender p bass. Stock pick ups. Ghs bass bommer round

 

[DWBass]

Bruh, return the amp!