Powering things: Power Supply limitations per outlet, etc.

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FreshChops

New member
Hey all, just getting started here. I love reading on here, but I'm getting active now and, well, am starting with a pretty basic question.

I have a variety of guitar amps that I often like to power simultaneously. I use a stereo looper (EHX 2800) and deal with a lot of ground hum tying in amps powered by different wall sockets and different power supplies. I guess the obvious solution would be to tie all of the amps power into one power block. My thing is, I have a small phobia "blowing things"!

My wall sockets are typical grounded, two prong outlets. I could probably get into the circuit breaker for breakdown of what's covering those areas if helpful, but in short, I'm pretty ignorant regarding power and ironically, don't like getting electrocuted :eek:

So in summary, I am powering combinations of 30 watt to 100 watt tube amps. In most cases, I would have 4 amps going.... yes, even tied into one signal, or the looper. Commonly, (2) 30 watt; (2) 100 watt

Would plugging them into the same power source eliminate ground hum between the amps?

Is there a general rule of thumb regarding how much to power from one outlet?

A third "?".... in addition to the tube guitar amps, could I / should I also power my pedal board from the same outlet. I have some high wattage pedals, like tube powered compressors.....

and another: In addition to this..... I have a high wattage bass amp, a 1200 watt SS bass power amp. aaaaa, can this be throw on the same outlet?

Honestly, pardon my electrician ignorance, but I'm serious and wouldn't be surprised if I'm overthinking this and there are little amp / gear limitations per outlet, or the reality that I should split loads as often as possible.... please enlighten me....

I also have a lot of options for quality power supplies, like good surge protection blocks. I even have a couple good battery backup supplies... Would these be benificial? What about a good "Furman" to power all amps. Would this help, or does it come down to limitations per outlet?

Thanks for any input..... my home recording studio is quickly coming together, I'm excited and I swear any other issues won't be so long winded.... :drunk:
 
I think your cool, just take a look at the breaker box I bet that your on a 20 amp breaker at that outlet and I'd say your only drawing 7 to 10 amps.
 
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Outlets don't care how many items you plug into them. The circuit does however.

As Moresound indicated, don't exceed the amperage rating of the circuit leg you're on.

Add up all of the current draw of what you need to plug in and make sure it's less than the rated breaker in the box.
 
Tube amps are really inefficient though, keep that in mind. Their power draw is going to be probably more than four times their rated output, even with a class AB push-pull output.

The solid state bass amp will be class AB, and has no heaters to waste power. So its power draw will vary significantly with volume. I doubt you will use 1200W in your house :eek:

Pedals use a very small amount of power.

You can buy a little plug-in wattmeter at the Orange Box if you are unsure . . . or you can just plug everything in and see if it trips your breaker :D
 
Great info here.... thanks! I have just ordered a watt meter from newegg. This will be very helpful, good suggestion.

I also looked over most of the amps and they vary from 1.5 to 4 amps and one at 7 amps. The 1200 watt bass ranges from 3-12... pretty extreme, but I'll do some math when using it on the same block.

In regards to ground hums, electricity filtering...... would powering them through a high voltage Furman clean up hum... how about an APC battery backup unit? I'm not experiencing much hum, but in regards to recording, want to be prepared.
 
Well if your experiencing a little hum,your good. I think that's just the nature of the beast with guitar amps, a little is to be expected when turned up to 11. Pedals introduce noise also.
I don't think a furman is going to help much maybe a hum eliminator, but that is only for extreme cases, Just turn down a little and make a few fine adjustments and you'll be good.
Are your guitars single coil or double style pick ups? Depending the style of pick up will determine hum and you may need to ground your guitar.
 
Just a correction possibly, in North America, standard 120 volt circuit breaker is 15 amps. If wired properly, you can tell by the shape of the prongs. Regular prongs like this ll are 15amp. If one is T shaped, then it is 20 amp.

Regardless, more than likely, 15 amp is the magic number and if you draw more than this, you trip the breaker, but it doesn't hurt the equipment, it just has the power suddenly shut off.

Grounding, ground loops etc is a whole other story. I am amazed at how many houses and buildings are grounded improperly. Also, polarity reversed, which can cause problems for some electronics.

A power conditioner though not necessary, can be very helpful for smoothing voltage spikes and hum problems too. Another thing, like moresound mentioned, guitars by their nature have hum, but one of the easiest and cheapest fixes is to properly shield the pickup cavity. Even a lot of high end, expensive guitars have poorly shielded pickups. Have a look at this article!
http://www.guitarnuts.com/wiring/shielding/shield3.php
 
yes, almost for sure going to be 15 amps unless maybe you have a 20amp fridge circuit? As above, look for one hole to be T shaped (you can use a regular plug, no need for that to be T shaped). And also, be aware that the 15 amps is the sum of *everything* on that circuit, not just your one outlet that you are using.

I'm currently running everything off a 15amp circuit, no problem. There's no danger, just that when you hit the limit, the circuit breaker is going to pop.

As for the guitar buzz, youre going to be stuck with it, probably even if you run a whole new circuit. I had a room once where if i was pointing due north or south the buzz would be greatly diminished, though. You might see if its less pointing a certain way. The only thing that helped that room was humbucker pickups. Cured it instantly. HTH
 
One thing I did when I wired up my home studio was to run a 30A circuit from the main breaker to the garage loft, where my home studio was to be.

Hardwired into that circuit is a 3000W UPS, happens to be a 15 y/o Compaq that's made by Deltec, but what it is doesn't matter.

My studio runs off that UPS. It provides 25 amps of 120V power, all day, every day, and also filters the power so it's clean and noise free.

Hum from stuff in the house doesn't get past. Brownouts are irrelevent. With a power failure I have to shut everything down of course before the battery runs out, but I have 10 minutes to do so. The PC, connected to the UPS with an RS232 cable, shuts down automatically just in case I've left the room "for a moment" which for whatever reason always ends up being far more than a moment.

Anyway, I found this to be a worthwhile investment - clean, filtered power, always at 120V regardless what the power company is doing, and enough time to halt work and shut everything down cleanly without crashing hard drive file systems on the PC as well as my hard disk recorders.

Also, because of how this old Compaq is wired internally, all three outlets are in parallel, with 15A breakers in the hot lead. This eliminated many hum problems for me as well.

While UPS units in the 3000W range are rather large, the advantage is you can run your whole console room on it. Used ones aren't terribly expensive especially if you ask the auction seller to remove and toss the batteries before shipping - that's probably 80-100lbs of weight right there. You'd want new batteries anyway, just for peace of mind.
 
The power conditioner will probably do little about hum, the worst of it is induced from EMI into your pickups and secondarily cable. Be careful with UPS, make sure they are rated to take the load. If you want a full 15A UPS, it will be big and heavy. My 6A UPS is the heaviest 2u bit of rack gear I've ever seen :eek:

A voltage-regulating UPS could make your hum worse, because they have large transformers that are kinda dirty as far as EMI. The really good isolation-transformer or pure sine-wave inverters are not cheap, and probably way overkill for guitar amps, which are noisy by nature anyway.

Reversed polarity wiring is stupid and dangerous, but it shouldn't affect properly wired guitar amps, since hot and neutral should go straight to power transformer and nowhere else, except through a fuse/breaker and switch. But there are some older amps that are not properly wired . . . always check your outlets with a tester if you are unsure.
 
mshilarious said:
The power conditioner will probably do little about hum, the worst of it is induced from EMI into your pickups and secondarily cable. Be careful with UPS, make sure they are rated to take the load. If you want a full 15A UPS, it will be big and heavy. My 6A UPS is the heaviest 2u bit of rack gear I've ever seen :eek:
Click to expand...

It depends on the unit though, the come in all different efficiencies, filtering styles and options (some have none!), and so on. This old beast I was referring to is massive and heavy - 4U, 200lbs with four batteries installed, according to my bathroom scale (assume it's not terribly accurate).

It be heavy!

mshilarious said:
A voltage-regulating UPS could make your hum worse, because they have large transformers that are kinda dirty as far as EMI. The really good isolation-transformer or pure sine-wave inverters are not cheap, and probably way overkill for guitar amps, which are noisy by nature anyway.
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That's a really good point, and admittedly I didn't think about that. My Fender cybertwin plugs into a room outlet (not on UPS) but I take s/pdif out so I've not had any hum amp to console, just guitar to amp which I imagine most everyone struggles with.

mshilarious said:
Reversed polarity wiring is stupid and dangerous, but it shouldn't affect properly wired guitar amps, since hot and neutral should go straight to power transformer and nowhere else, except through a fuse/breaker and switch. But there are some older amps that are not properly wired . . . always check your outlets with a tester if you are unsure.
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Again, that's excellent advice. BTW, Good to see ya Ms H :)
 
frederic said:
That's a really good point, and admittedly I didn't think about that. My Fender cybertwin plugs into a room outlet (not on UPS) but I take s/pdif out so I've not had any hum amp to console, just guitar to amp which I imagine most everyone struggles with.
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Again it's not from a loop, it just flies around magically through the aether . . . :D

Seriously, it's a magnetic field from the transformer. So you need to keep amps, guitars, and cables away from it. Usually not too hard, but something to think out.

I also don't see why an amp needs to be plugged into a UPS.
 
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