Oblivion DC
Active member
Copperhead":223cd said:
Again, you're defeating the AC ground on the amp and that's not a good idea.
Again, you're defeating the AC ground on the amp and that's not a good idea.
Oblivion DC
Active member
I don't know for sure but you might wanna give that a try. If you get the adaptors from GC and they don't work out you can always return them.UVguy":84ef1 said:
C
Copperhead
New member
Oblivion DC":18f4c said:
If you have a ground loop, you are grounded at least twice. Nothing unsafe about lifting the ground on one of the devices, be it the effect or the amp. When running two amps A/B with a talk box, you have to lift the gorund on one of the amps. With everything unplugged from power, yet the guitar and effects etc. all connected, check for continuity from the bridge of your guitar or from the barrel of the instrument cable to the ground pin on whichever device you do not lift the ground on, if your meter says continuity, then you are grounded, yes, it's that easy.
Oblivion DC
Active member
EightmanVT":3813e said:
I was kinda curious about that myself so I had a quick look around.
Here's a bit from an article on the history of the Yardbirds:
lead singer Keith Relf, bassist Paul Samwell-Smith, rhythm guitarist Chris Dreja, and drummer Jim McCarty, were local heroes. Like many English rockers, they met in or around school, and saw music as a way out of an ordinary life. Keith Relf had worked as an electrical engineer for Samwell-Smith's father, an irony given his death in 1976 by electrocution from an ungrounded guitar amplifier.
1972 ----- Harvey, Les ----- Stone the Crows ----- 27 ----- electrocution on stage
1973 ----- Rostill, John ----- the Shadows ----- 30 ----- electrocuted while playing guitar
So not a ton of people, and none all that recently either. Probably because folks found out how dangerous an ungrounded guitar amp can be and spread the word. It can still happen though, so watch your ass.
Oblivion DC
Active member
Copperhead":f5910 said:
So - real question here, not trying to be sarcastic - when you're using a switching system through your effects loop, if you have one amp with a defeated AC ground, and you switch off the effects loop do you still have a safely grounded rig? Or did switching the loop out of the circuit remove your only ground as well?
UVguy
New member
Copperhead":8227c said:
So you are sure this is safe? I will give this a shot. Lift the amp and see if it goes away. The amp is plugged into a proper powerbar then into the wall.
S
Sacha
New member
UVguy":b468e said:
I would try that or batteries before lifting any AC grounds, especially if you don't really know what you're doing. Also look into the isolation transformer like the Ebtech linked earlier.
Another option is just use your noise gate out front, that should still get rid of most of the noise anyway...
UVguy
New member
Article here explains lifting the ground on the amp...
https://www.premierguitar.com/archive/mo ... /08_02.htm
https://www.premierguitar.com/archive/mo ... /08_02.htm
Oblivion DC
Active member
If you read it carefully he does say that usually he lifts the ground on the pedal.UVguy":f59ae said:
UVguy
New member
Hmm...my pedal adapter is only 2 prong, so it can't be lifted.
Oblivion DC
Active member
UVguy":9348f said:
Does the hum go away when you're only using batteries?
Does the hum go away when you're using two separate adapters?
Try both of those before you disable your AC ground prong.
C
Copperhead
New member
I'm seriously doubting you have a ground loop.
Do as others have said and try batteries in your boxes first.
Again, you can easily check for ground from the shield on your instrument cable or bridge of your guitar to the ground pin on any of your equipment.
Do as others have said and try batteries in your boxes first.
Again, you can easily check for ground from the shield on your instrument cable or bridge of your guitar to the ground pin on any of your equipment.
UVguy
New member
Well to clarify here, the batteries cleaned up the hum. Guess I'll have to live with the hum or just use batteries, which is too expensive imo.
C
Copperhead
New member
Try reversing the power adapter. Nuetral side is tied to ground in the US. Try a different power adapter instead of same power source for all your pedals. I've had a hum appear in older pedals when using a power adapter that was way "oversized" in amp draw. Check the power requirement and find a power adapter that matches closer. (milliamps)
UVguy
New member
What do you mean be reversing? Center ground instead of center negative, or simply reversing how its plugged into the powerbar? Tried 2 different wall warts and both produce hum/
UVguy
New member
bbbump
C
Copperhead
New member
Yeah, flip it 180 degrees. Read on the back of the offending pedal and check the milliamp requirements and get the correct matching transformer. If your "wall wart" says it outputs 12 volts at 1500ma and your device requires 9v @ 700ma, then you will have a hum.
If I got reaaaally frustrated with it, I would open it up and see if it has a seperate wire running to the shield side of the jack and open that connection, I'm talking about a ground from the power section of the circuit, not the signal path. We're trying to isolate the noise from the power. I've had this happen with keyboards and cheap direct boxes. Quick cure is snipping the second wire to the shield side.
If I got reaaaally frustrated with it, I would open it up and see if it has a seperate wire running to the shield side of the jack and open that connection, I'm talking about a ground from the power section of the circuit, not the signal path. We're trying to isolate the noise from the power. I've had this happen with keyboards and cheap direct boxes. Quick cure is snipping the second wire to the shield side.