DC power vs AC power

[Salt]

No bait

 

[Icarus88]

Then they probably changed that in the newer versions, it still worked with the 1st Gen.
As I said, the problem with the sensitivity setting of certain USB interfaces and the guitar grounding problem is well known, the solution is always to change the interface or guitar. There are ways to change something on the guitar, but that only reduces the problem and doesn't solve it.

You could also try using a DI-box or an effects device, that could also solve the problem.

By the way, you don't happen to have a very old monitor or even a tube monitor in the room.

No I have a laptop screen only
Thanks for your help.

 

[Icarus88]

I was sat around a table with some friends a while back, and there was a hifi just next to us. For whatever reason, we each put the jack to our temple to see who could make the loudest sound. My head made the loudest sound, so i came to the scientific conclusion that this must be a result of my powerful brain.

I'm disappointed to find out that we don't generate our own electricity, and that i might actually be stupid.

Anyway.

Why does the volume of this feedback vary from person to person (same jack/equipment)?

Are some people more receptive 'antennas'? If so, how?

If not, then...?

 

[Jimbob54]

I was sat around a table with some friends a while back, and there was a hifi just next to us. For whatever reason, we each put the jack to our temple to see who could make the loudest sound. My head made the loudest sound, so i came to the scientific conclusion that this must be a result of my powerful brain.

I'm disappointed to find out that we don't generate our own electricity, and that i might actually be stupid.

Anyway.

Why does the volume of this feedback vary from person to person (same jack/equipment)?

Are some people more receptive 'antennas'? If so, how?

If not, then...?

We arent doing this . Time out .

 

[earlevel]

None for your case. The third connection in the U.S.A. is for a safety ground. It ties to ground in the electrical service panel, along with the neutral (return) wire, and the hot wire goes to the breaker. The safety ground is to provide a secondary ground path in the event of a defective component or user error (like running a hair dryer in the shower).

Well...hair dryers have no ground pin because the case is plastic. Hair dryers in the US typically have a ground fault device for a plug, two-prong. You get the same functionality with a ground fault receptacle, but including on the dryer ensures you'll have ground fault protection even in old wiring and code standards, so it's law.

Which brings us back to what I said before. Grounds are typically for devices with metal cases (or partial, like a metal panel that has potential exposure to high voltage). A lot of audio gear is housed in metal, but just because it's metal doesn't mean it needs an equipment ground (wall-wart power, for instance).

Note: I have to add this public service message because I've had discussions with people who would say, "You can't have ground-fault protection if you have no ground!!!" No, these are two independent things. Ground fault detection occurs when the circuit guards against current being dumped through an illegitimate path to ground—which might be a person, or a through a connection that might be touched by a person or start a fire. Having an equipment ground is immaterial to detecting a ground fault. You can wire a GFCI (ground fault circuit interrupter) to old 2-wire home wiring. In fact, code usually demands it, if you're going to replace a broken 2-prong outlet, for instance.

 

[DonH56]

Well...hair dryers have no ground pin because the case is plastic. Hair dryers in the US typically have a ground fault device for a plug, two-prong. You get the same functionality with a ground fault receptacle, but including on the dryer ensures you'll have ground fault protection even in old wiring and code standards, so it's law.

Which brings us back to what I said before. Grounds are typically for devices with metal cases (or partial, like a metal panel that has potential exposure to high voltage). A lot of audio gear is housed in metal, but just because it's metal doesn't mean it needs an equipment ground (wall-wart power, for instance).

Note: I have to add this public service message because I've had discussions with people who would say, "You can't have ground-fault protection if you have no ground!!!" No, these are two independent things. Ground fault detection occurs when the circuit guards against current being dumped through an illegitimate path to ground—which might be a person, or a through a connection that might be touched by a person or start a fire. Having an equipment ground is immaterial to detecting a ground fault. You can wire a GFCI (ground fault circuit interrupter) to old 2-wire home wiring. In fact, code usually demands it, if you're going to replace a broken 2-prong outlet, for instance.

It was an example. I have an old hair dryer (from when I had more hair) that has three prongs and no fault protection at the plug. My wife's newer dryers are two-prong and/or have a GFCI at the plug.

Sometimes this place is too literal, pedantic, whatever.

 

[earlevel]

It was an example. I have an old hair dryer (from when I had more hair) that has three prongs and no fault protection at the plug. My wife's newer dryers are two-prong and/or have a GFCI at the plug.

Sometimes this place is too literal, pedantic, whatever.

OK. But I don't think I as being "too pedantic" at all. We are talking about grounding and you gave a specific example—and you (ground) fault me for taking it literally? Was I supposed to take it figuratively? (No, I didn't take it literally that you would take it in a shower, but that's not the part I responded to.) BTW, it's been code since 1987, so at least you have one sturdy hair dryer.

FWIW, a ground on a hair dryer is not all that safe, it doesn't stop current from flowing, it just gives it a better path if everything is working ideally. Local GFCI is a far better bet, because it stops the current flow and it's trivial to test.

Anyway, my point was that, in general, 3-prong plugs in the US are for products where the case has become hot in a fault—in other words, metal. It's not for all circumstance that could possibly kill you. Lamps, for instance, are rarely 3-prong, and they can kill you readily in the wrong circumstances.

The reason I'm making a big deal about this, is that it seems (I could be wrong) that some are relating ground loops to problems with grounding via the third prong. Or at least, I think some of the wording could be misinterpreted by others to imply that. You can have ground loops just fine with no grounds at all, with grounds on everything, or some with and some without.

I had ground loops up the wazoo in this room I'm typing in (separate building apparently added as a rec-room by a previous owner), and it was all 2-prong Romex till I had it rewired. Besides audible loops, if I was barefoot and my lip tapped my mic, I'd feel the sting. Not a ground loop since.

 

[Speedskater]

a Safety Ground and a GFCI perform two different primary functions:
1] Safety Ground trips a breaker or fuse if there is a Ground Fault (short circuit) between the Hot wire and the enclosure.
2] GFCI trips if there is a small amount of leakage current thru a human (or other).

 

[Icarus88]

@Icarus88
If it's about Focusrite Scarlett interfaces that you connect to your guitar, then you should look for them in the relevant specialist forums.
This is a known problem with the sensitivity and sensitivity setting with the Focusrite Scarlett interfaces and many guitars (keyword: incompatibility), as well as the generally somewhat difficult issue of grounding with guitars. As far as I know, this can usually only be resolved by using a different guitar or a different audio interface.

Does your guitar happen to have its own battery or power supply?

Addendum: This problem cannot be solved with a USB isolator, it is simply due to the inappropriate sensitivity of the interface.

I solved it with the USB isolator, thank you, but only if the EQ pedal I connect the guitar to is powered by battery. The ground loop hum that I got with the same EQ settings is gone now, I set the EQ setting higher but it still doesn't exist,I don't get any ground loop hum anymore. Because cheap interfaces don't have isolation.