#1
I am getting a hum whenever my amp is on but I am not playing anything. It is not feedback, I am holding the strings. The noise is just a persistent, mid-range hum. I have found that the potential cause of this is a Ground Loop at 60 Hz. What pedal/rack gear/something can I use in my setup to eliminate it? Thanks.
Epiphone Les Paul Custom Silverburst 500t/490r
Mesa Boogie Single Rectifier Rect-O-Verb Series 2 Head
Carvin vt412 4x12 cabinet
#2
Don't buy something to mask the problem. Find the ground loop and do something about it.
First thing to check is the wiring of your guitar and the cable. Could also be a bad preamp tube or reverb pan.
#3
I have tried it with multiple 600 dollar plus guitars and it still makes the hum. I bought the 6505+ brand new and it always did this, even with a straight head to cabinet setup, no pedals or anything. It has also did this with all input cables I have used through it. Even if something has problem, how exactly do I "check wiring"? Check for what?
Epiphone Les Paul Custom Silverburst 500t/490r
Mesa Boogie Single Rectifier Rect-O-Verb Series 2 Head
Carvin vt412 4x12 cabinet
#4
If it does it with nothing plugged in you should check your tubes. A good test is to turn the preamp volume and gain all the way down- if the hum goes away you know the noise is in the preamp. If the noise stays you have a bad power tube or an issue in the B+ supply.
Keep in mind that it's a high-gain amp, and one designed more for economy than unyielding performance, so a certain amount of hum is to be expected.
#5
Yeah, if I play my amp on clean, I can play it really loud with barely any hum at all, on distortion it is pretty heavy though. I suppose one of the stock preamp tubes is bad?
The hum changes in loudness when I move the guitar around. Come to think of it, however, I believe my solid state amp also hummed whenever I wasn't playing. Does this mean my pickups are wired wrong? What do I look for, why the **** were they wired wrong?
Epiphone Les Paul Custom Silverburst 500t/490r
Mesa Boogie Single Rectifier Rect-O-Verb Series 2 Head
Carvin vt412 4x12 cabinet
Last edited by Karg45 at Oct 15, 2008,
#6
Hum to some degree is normal on any amp.
Hum that changes when you move your guitar could be due to being too close to the amp, having fluorescent lights on, etc.
More gain will induce more hum, so it's possible that your preamp tubes are fine. Try turning the gain down on the distortion channel so it's similar to the clean channel (that might not be possible on that amp, but turn it all the way down at least) and compare the amount of hum. The 6505+ uses three full 12AX7s for the gain channel, so any of those could be bad.
#7
I will try to get a sound clip up of what is happening. If hum is normal, then I suppose I should get a noise gate then.
Epiphone Les Paul Custom Silverburst 500t/490r
Mesa Boogie Single Rectifier Rect-O-Verb Series 2 Head
Carvin vt412 4x12 cabinet
#8
isp decimator if you start looking at noise gates
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