Ground loop

[Coytee]

Question...

I've been told by a friend that to help make sure I minimize any chance of ground loop, I should have everything hooked into the same circuit breaker.

Am I preparing to screw things up?

Downstairs (unfinished), I only have a couple outlets. I am in process of finishing the basement and have added a 100 amp breaker box that I intend to run a power line to. Then, out of this panel, run lines to various places in the basement BUT SPECIFICALLY, I intend to run a DEDICATED line on ONE breaker to each Jubilee (in case I ever put an amp near them). Meaning, each Jubilee will have an outlet next to it and this outlet will be on it's OWN breaker, they will not be on the same circuit. I am also going to put like five or six seperate outlets, also on SEPERATE breakers so each outlet can't be overloaded like I feel I'm doing now.

I currently have on one breaker, both amps when I'm using both (one is tube), preamp, TV, cd and dvd players, telephone... In fact, most of the stereo stuff is jammed into a single outlet which I detest. Since this is temporary, I'm dealing with it. My "fix" for that was to make it possible downstairs where it would be near impossible to overload a single outlet (breaker) because I intend on having each outlet fed by its own breaker.

I decided on each outlet (near the stereo stuff) to be on a circuit because I simply have the space to do so. I'm NOT concerned about adding more wire expense in the walls for the dedicated runs. For the "room" outlets, I'll run those like you normally would.

So, by doing that, am I begging for ground loop issues?

If so, then what might be a better way of doing it? I really don't want a 100 watt tube amp, tube preamp, second solid state amp, cd players, dvd players, big screen tv's all plugging into a single socket.

Thoughts ??

[Guest " "]

"Am I preparing to screw things up?"

yes...maybe

You have to make sure the breaker is reated at 2 - 3 times the value of your highest single componet. So if you have an amp that says 1100VA's on the back UL label next to your power cord, you need a circut that can handle 2200 - 3300VA's . That translates to about 20 - 30 amps. If you use a 15 amp line, you will be popoing breakers and/or causing line surges.

If you have 2 such amps, your headed for trouble, and will have to turn them on indiviually.

you said

" I am in process of finishing the basement and have added a 100 amp breaker box that I intend to run a power line to"

but thats just to the main bus....what are the individual runs from the box to your outlets going to be. 15A, 20A, etc. You can't put in a 100 amp box and not use individual circut breakers for the various lines you will run from that 100 amp box.

[Coytee]

but thats just to the main bus....what are the individual runs from the box to your outlets going to be. 15A, 20A, etc. You can't put in a 100 amp box and not use individual circut breakers for the various lines you will run from that 100 amp box

I didn't realize it might be interpreted differently. I intend on this second box to have a breaker for EACH outlet that is going to be associated with my stereo stuff. Meaning, let's suppose it might have 10 breakers (I'm making that up, it might hold 20 or 10)

anyways, I'll have a couple breakers in that box for my downstairs & garage outlets. I will then run 12-2 wire to EACH outlet so the 5-7 outlets I might have dedicated to my stereo stuff will EACH be on its own breaker.

If 12-2 wire will do 20 amps then that's wonderful. If it will only do 15 amps, that's cool too. I'd like to think that 12-2 would be enough if it only has to deal with ONE amp on it. I was going to buy those orange colored outlets so it would be cleaer which outlets are "special" but the wife is trying to put the NIX on that.

My brother in law is an electrician so nothing will be done here by me. I'm just going to be the grunt to run the wires. He will be the one doing the actual electrical connections.

Big reason this bugs me... upstairs where I've got a zillion things plugged into the circuit... when the wife brings out the vacume cleaner, there are times that the vacume is enough oomph to trip my breaker. That has told me that I'm already running the circuit at 50 or maybe 70% (just a guess).

[Guest " "]

most wire charts will tell you 12-2 is good for 20 amps, but the total lenth of the wire is a factor. your electrician will certianly know. what he won't know unless you tell him is how you plan to load the circut he is recommending you use. electricians may not be into audio gear and he may not know what you amps max current draw is and what their in-rush currents are.

The problem your having upstairs with the vacum is the problem I'm talking about. If you load all your hi- draw gear on one breaker.....you need to make sure it's at least a 20 amp circut. I've had countless amps that draw enought to pop a breaker due to their inrush currents. most of those I've left on to avoid the issue.

Talk to him about in-rush currents. If he does not understand it, find another electrician.

[Islander]

If 12-2 wire will do 20 amps then that's wonderful. If it will only do 15 amps, that's cool too. I'd like to think that 12-2 would be enough if it only has to deal with ONE amp on it. I was going to buy those orange colored outlets so it would be cleaer which outlets are "special" but the wife is trying to put the NIX on that.

Those orange outlets are pretty eye-catching and can look out of place in a living room. As another way to go, you could use 20-amp outlets, which come in white and look normal, except for the T-shaped slot on one side, an unobtrusive identifier. They're only a little more expensive, but make a better connection, due to stronger springs and more contact area. I was told that 20-amp sockets are required for kitchen outlets here in the latest electrical code.

You could also use hospital-grade sockets, which make a good connection, but are somewhat more expensive. They have a green dot, so you can easily spot them, but they are available in white and don't look out of place.

[PositivAttitude]

Coytee, For qualification, I'm no electrician.. I understand what you're doing and think it a pretty good idea. That and especially since NOW is the time to do it, questions and all - during your construction. MY only input... Don't forget to purchase those $150.00 outlets I saw in the magazine the other night

[Coytee]

Don't forget to purchase those $150.00 outlets

Good thing you said that with 'PositiveAttitude' else I'd have to sic Chloe on you! She can lick to the center of a Tootsiepop in record time!

[]

[Andy W]

http://forums.klipsch.com/blogs/andyw/archive/2007/11/30/hum-and-buzz-part-iii.aspx

Here's why you don't want to run two circuits. ^ ^ ^

[ClaudeJ1]

but thats just to the main bus....what are the individual runs from the box to your outlets going to be. 15A, 20A, etc. You can't put in a 100 amp box and not use individual circut breakers for the various lines you will run from that 100 amp box

I didn't realize it might be interpreted differently. I intend on this second box to have a breaker for EACH outlet that is going to be associated with my stereo stuff. Meaning, let's suppose it might have 10 breakers (I'm making that up, it might hold 20 or 10)

anyways, I'll have a couple breakers in that box for my downstairs & garage outlets. I will then run 12-2 wire to EACH outlet so the 5-7 outlets I might have dedicated to my stereo stuff will EACH be on its own breaker.

Geez, you guys have reached the "insane level." We are talking about Jubilees that give you 108 db for a 1W input. I get similar efficiencies from my MWM/Lascala combo. Woofers use WAY more power than mids and tweets, yet I just measured about 13 MILLIWATTS per channel at normal listening of 88 db, which is fairly loud when sitting 10 ft. away.

Why in the heck would I need 30 amp circuits (current square times voltage is power) which translates to about 9 Kilowatts, or close to one MILLION times more power than average listning.

"Splain it to me, Lucy!"

[mas]

Why in the heck would I need 30 amp circuits (current square times voltage is power) which translates to about 9 Kilowatts, or close to one MILLION times more power than average listning.

"Splain it to me, Lucy!"

Easy.

Current ratings are not done for the purpose of how loud you want to listen to a system. They are done for safety.

A prime example is the Crown Macrotech series that, by UL ratings, requires a 30 A service. And no, that is not because they can 'play loud', but it is simply because of the robustness of the circuit. In the event that the load on this amp is short circuited intoa dead short, unlike almost every other amp you can name, the Crown will NOT shut down! And it is capable of drawing 30 Amps!!!

And anyone who doubts this never had the fascinating experience of seeing one operated in such a condition. Its commonly refered to as "welding". And these amps will indeed do that and then you can re-connect them to a 'normal load' and they continue as if nothing unusal has happened. Aside from incidental occurances of this scenario (and I can speck from experience, you will never forget having a speaker lead with banana plugs falling onto a mstal bench and shorting and then 'hopping about'!), Crown used to demo these amps and their robustness for road use by demonstrating their ability to weld and keep on ticking..

Thus you have a choice. You can provide the rated service, or you can enjoy the fire that results from an overheating of the service. And no, the service does not necessarily shut down before thermal damage occurs.

[LarryC]

Those orange outlets are pretty eye-catching and can look out of place in a living room. As another way to go, you could use 20-amp outlets, which come in white and look normal, except for the T-shaped slot on one side, an unobtrusive identifier.

I agree -- when I had two 20-amp isolated-ground circuits installed, the available colors were the gaudy orange, ivory and gray. I chose gray because it's both understated and distinctive (and ivory would not have gone well with the off-white walls).

[Andy W]

Why in the heck would I need 30 amp circuits (current square times voltage is power) which translates to about 9 Kilowatts, or close to one MILLION times more power than average listning.

Power = Current times Voltage

30A * 120V = 3600W

It's very easy for modern subwoofer amplifiers to use ALL of the 15A on a standard house circuit. (1800W) Usually the voltage sags quite a bit though, and you don't get full power. How much it sags depend on how far away your amp is from the transformer, and how much power you and your neigbors are using at the time. Here in our building I've measured the RT-12 amplifier as it sucked the lined from 117VAC down to 103VAC.

As for the Jubilees... We had a pair of them here for the Pilgrimage, and just for fun a hooked up a 2x20W amplfier... it wasn't quite enough to get them really good and loud... it was loud enough for almost all of my listening though.

If I were biamping, 20W might be OK for the top end, but I'd probably use my 2x60 amplifier, and for the bottom end 2x300 would work out nicely. 100W would probably be my minimum.

Most often though 2x20W would be more than enough.

Sorry for the hi-jack.

[Coytee]

100W would probably be my minimum.

I think you & I would get along very nicely...

Back to topic...

I've only glanced (as opposed to stare on hours) at your diagram in the blog to try to understand it...

Remember you are (probably) some kind of an engineer and I am the proverbial dumb as a brick public person...

Soooooooooooo in words I can understand, lemme ask this:

In simple terms, are you saying it's a WORSE idea for me to have a subpanel for my basement and in that subpanel, have individual breakers for EACH outlet that is planned for my stereo system? I thought it was a stroke of brilliance. This way, NO single outlet gets stressed and each amp has its own power supply. Aside from that, I don't mind so much if my cd player, dvd player and another odd/end share a circuit. I'm just trying to be able to divide my load among several breakers and the only way I can make that 100% foolproof, is to have each outlet on a breaker (and I don't mind paying for the extra wire/pain to make that happen)

So, if you are saying it's a bad idea to have say, 4 outlets and therefore 4 breakers power my system, that would infer "fewer is better" and as such, don't I now risk stressing a single breaker? Should I run a 4 gage wire with a ?? breaker on it so I can simply do a massive outlet multipler and have everything plugged into one source?

btw, my brother in law is an electrician so don't think I'm playing around inside my panel boxes. You don't need those disclaimers here. I don't know though, that my brother in law would be very concerned about any ground loops or hum. He'd simply go to the boxes, pull the wires, connect the wires and be done. That's one reason I've got a semi-overload upstairs. I've got several plugs on one breaker and when the stereo is on, if the wife turns the vacume cleaner on it will at times, trip the breaker. It's that kind of stuff that I'm also trying to 100% factor OUT.

[michael hurd]

Isolated transformer ( on pole outside house ) and I can sag the line enough with ONE QSC PLXII amp that it will momentarily shut down. Real amps need large wire, breakers and so on to perform best.

During one session, I tripped the breaker 6 times, this amp is driving my subwoofer. MAS, do you know anyone with a small distro>? Peavey markets one with a range plug on it, but is is also about $ 599.

[Guest " "]

You folks are talking about line sags related to peaks an amp may produce......and all those theories are plausible.

My initial comments comments have to do with inrush currents related to turning on amp gear and even some TV's. My TV will flicker the lights on the second floor. I had a few crown amps that used only 800VA's at full power, but would draw 2500VA's in inrush currents to power up. The owners manual of a lot of this type of gear will go as far as saying to put delay turning on your amps. Some amps will just never power up on a 20 amp line. Try powering up a pair of SAE 501 amps. At max power, each draws 1500VA's, inrush current each 4500VA's.

Now the buisness of inrush currents during power up can raise havic on your other gear. Hence the power up sequence built into a lot of line conditioners that power up amps first and low powered devices last and vs versa.

How much power do you really need...depends on the inrush ratings of your gear and their max power draw if you ever get to max power.

A lot of folks use voltage regulators....mine is 2000 VA's, it sits in front of a 5000VA balanced power transformer that connects to both phases of my mains so it's 220 in and 120 out. The 220 line is a 60 amp line. The transformer feeds my regulator with 60-0-60. That then feeds a power conditioner.

[DrWho]

Geez, you guys have reached the "insane level." We are talking about Jubilees that give you 108 db for a 1W input. I get similar efficiencies from my MWM/Lascala combo. Woofers use WAY more power than mids and tweets, yet I just measured about 13 MILLIWATTS per channel at normal listening of 88 db, which is fairly loud when sitting 10 ft. away.

I would wager that your peak power draw at those listening levels would be closer to 13W - assuming the music has transient peaks in the range of 20dB. 100W is just under 10dB more than that, which could quickly come from 10dB more dynamics in the music...

I can't help but wonder if the reason that horns sound so efficient (compared to direct radiators) is simply because the amps don't have to clip to drive them...

[Guest " "]

"I can't help but wonder if the
reason that horns sound so efficient (compared to direct radiators) is
simply because the amps don't have to clip to drive them... "

Ah yes, weed hopper....you have traveled the path of the rice paper and there are no foot steps...it is time

[Arkytype]

Speakerfritz offers the best solution for eliminating ground loops/hum/etc.----balanced power. It works everytime.

http://www.furmansound.com/pdf/datasheets/IT-2315_datasheet.pdf

The second best choice is to use the isolated ground receptacles. 20 amp service using #12 wire and 20-amp receptacles is the wat to go. For best integrity, don't strip the #12 wire and stick it into the hole--use the screw terminals.

If possible, power your technical gear from the same 120 volt leg. Put the beer cooler, mood lighting, and lava lamps on the other leg.

Lee