Use of the ground lift make bad sound?

[Kasper]

Hi
I have JC1 connected to my B&W 802N. Will the use of the ground lift make the sound worse or change the sound quality?
Look forward to read the feedback from you.

Best regards
Kasper from Norway.

[Peter Nielsen]

No, but ideally you should locate the source of the hum and fix it properly so that you do not need to rely on the switch. (For instance, if the hum is caused by your cable box, then equip it with a Jensen filter and all should be good).

Peter

[Kasper]

No, but ideally you should locate the source of the hum and fix it properly so that you do not need to rely on the switch. (For instance, if the hum is caused by your cable box, then equip it with a Jensen filter and all should be good).

Peter

Thanks Peter for fast feedback. The reason I am asking for this issue, I have plans to find a new spot for my JC1 amp. But then I need longer signal kabel RCA (unbalanced), but receive some hum when the kabel geting longer, about 5-7 meter. 1 meter don't have hum. I am aware not put cabel close to transformer etc... and don have balanced on my preamp. When I use the lift switch no noise, super quit!

Best regards
Kasper

[Peter Nielsen]

In that case using the ground lift makes sense. If all audible noise disappears with the ground lift, you should be fine. No worries.

Peter

[wettou]

In that case using the ground lift makes sense. If all audible noise disappears with the ground lift, you should be fine. No worries. Peter

I read that you are not supposed to use ground lift as it can damage the equipment is that so? What are the main reasons for ground anyway?

[Chris D]

The purpose of a ground in any electrical object or connection is preparation for the possibility of a fault. As we know, electricity will take the path of least resistance. So in the case of a fault, such as a live wire touching an appliance casing, instead of burning up the casing, the ground will allow the electricy to flow to the destination that has the overall least resistance--literally the earth, or ground, that the house electrical system is connected to, and nobody gets electrocuted.

[Peter Nielsen]

I read that you are not supposed to use ground lift as it can damage the equipment is that so?

That information is not correct. (Well, ok, if the unit is not grounded and you pour water on it it may burn out your preamp and other equipment in the chain).

What are the main reasons for ground anyway?

To protect you. Suppose that you pour water on the unit. Water is conductive and if you are very unlucky and the water happens to only get between the live wire and the chassis, then you have an amplifier that could be deady if you touch it. However, if your preamp is grounded it is possible it would take the hit and in the best case all that happens is a blown fuse (and possibly damaged preamp).


Peter

[wettou]

The purpose of a ground in any electrical object or connection is preparation for the possibility of a fault. As we know, electricity will take the path of least resistance. So in the case of a fault, such as a live wire touching an appliance casing, instead of burning up the casing, the ground will allow the electricy to flow to the destination that has the overall least resistance--literally the earth, or ground, that the house electrical system is connected to, and nobody gets electrocuted.

So if an amp has no ground are they a potential safety concern? I found that taking the ground off helps eliminating ground loops :B

[joetama]

That information is not correct. (Well, ok, if the unit is not grounded and you pour water on it it may burn out your preamp and other equipment in the chain).



To protect you. Suppose that you pour water on the unit. Water is conductive and if you are very unlucky and the water happens to only get between the live wire and the chassis, then you have an amplifier that could be deady if you touch it. However, if your preamp is grounded it is possible it would take the hit and in the best case all that happens is a blown fuse (and possibly damaged preamp).


Peter

There would be no need for water to be involved. Without a ground there is no path for the electricity to follow, except into your other equipment or into YOU!!! I personally would say that isn't a good thing in any case especially if you have expensive or high quality equipment or value your life/safety and the lives/safety of others. Safety grounding is there for a reason and is nothing to play with.

That being said, using the Lift on the Amplifier back is perfectly ok and should not affect the sound what so ever.

But, lifting the main ground with the use of a 'cheater' plug is not ok.


The best thing to do is to isolate which piece of equipment is causing the buzz/humm and solve it with either isolation though a proper device or common grounding of everything. (The use of the switch on the JC1 is probably fine, I'm assuming that the input circuitry is designed to lift the ground from the signal input to help isolate the ground, or it isoltates the input of the amplifier from the common ground, but I doubt it takes away saftey ground.)

[Peter Nielsen]

I doubt it takes away saftey ground.

That's correct. The ground lift switch on the JC-1 does not remove safety ground. (Because of this, the switch does not always help to eliminate hum).

As for safety: In Europe regular indoor wall outlets are not grounded! Grounded sockets are required only in some areas (bathroom, kitchen, etc).

Remember that Europe uses 230V, and the JC-1 is considered safe to use in Europe (despite no grounding).

So it's safe! Below is an image of an ungrounded European household outlet. (The silvery thing in the center is a screw that holds the cover plate in place).

NOTE: Because a ground connection is not guaranteed in Europe, the safety requirements for electronics are higher. For instance, all mains switch must break BOTH the live and neutral because the plug is not polarized. Consequently, you could say that it is safe to use a cheater plug on any gear that is CE-marked (required for sales in Europe). If the gear is not CE marked, be careful with cheater plugs! You don't know what awaits you....

Peter

[joetama]

If the gear is not CE marked, be careful with cheater plugs! You don't know what awaits you....

Peter

Quoted for truth.


I usually just recommend not lifting the AC ground at all because some folks get carried away with it.



Something the OP could try just getting a junk extension cord (or any piece of decent gauge copper wire) and hacking the ends off and common grounding the chassis of the amplifier, preamplifier, and sources to a earth ground.

Or you could even 'cheat' a balanced connection by using the + & - as normal and using a third shielded connection connection to both chassis. Similar to the method above but it offers then EMF & RF protection with decent ground noise rejection all in the same cable, if using a true 2 conductor + shield conductor cable. I've used this before in a few cases of noise problems. But, it all really depends on if the ground on the unbalanced input of the JC1 or the output ground of the preamplifer is just audio signal grounded or if the ASG is bonded with chassis ground as well.

I've had luck with star grounding eveything when I had a noisy cable box. But, in all reality the switch on the amplifier is fine to use. Probably just changes from chassis ground to earth ground. I just like to know where my humm/buzz is coming from.

[Peter Nielsen]

I've had luck with star grounding eveything when I had a noisy cable box.

FWIW, the Jensen VRD-1FF cable TV isolator works beautifully to eliminate cable box problems. (At times, you can find the VRD-1FF for as little as $15 on eBay).

I just like to know where my humm/buzz is coming from.

Same thing here. Usually you get a ground loop problem once you need to use two power circuits for equipment that is interconneted (good example: DVD player and remote projector on two separate power circuits and interconnected with video cable). With a single circuit and no antenna/cable connection, there seldom is a problem.

Peter