[zybar]

I am seeing a fairly substantial drop in my outlet voltage when I have my complete system running and I am not sure why it is happening.

All gear (see list below) is on the same circuit and nothing else in the house is on this circuit.

With nothing turned on, the outlet measurement is a little on the low side (around 117-118 volts), but is consistent with measurements I get from other outlets around the house (on various circuits).  When the gear is turned on, the outlet voltage can drop to as low as 104-105 volts.

I am taking all measurements with a multimeter (Greenlee DM-20) or I can measure via a Monster AVS-2000 voltage stabilizer.

List of gear:

Atma-Sphere MA-1 amps (consume 500 watts each)
Rawson built Pass Aleph J clone (about 20-25 watts Class A - not sure how much power it consumes)
Modwright Transporter (not sure how much power it consumes)
Behringer DCX-2496 (high modified and I am not sure how much power it consumes)

Thanks in advance for your thoughts and comments.
George

[IronLion]

I know nothing about electricity, but doesn't it make sense given how much juice your Atma-Sphere amps and the Aleph J in Class A would consume? 

[zybar]

I know nothing about electricity, but doesn't it make sense given how much juice your Atma-Sphere amps and the Aleph J in Class A would consume? 

I am not sure, which is why I posted.

I would think that a 15 amp line could handle the demands without dropping that much in voltage.

George

[sts9fan]

That Aleph consumes around 200 watts idle I think. 

[acwd1950]

Lots of things can make it do that. Wire size from the breaker box to the outlet. Bad connection somewhere in the circuit. How far the outlet is from the breaker box. Lower voltage coming from the power co. Where you are on the power companies line, how many houses on that line, etc.etc.etc. Sounds like the wire size from the breaker to the outlet is on the small size. JMO. You can figure the amp that your equipment pulls by taking the watts and dividing it by voltage and get amps. You could also get a clamp style amp meter and get a close amperage draw that way. All you have to do is put the clamp around the cord and it tells you what the amperage draw is on that cord. Higher amps equals lower voltage if the wire size is too small or too much resistance from a bad connection.

Steve

[mgalusha]

The DCX only consumes a few watts, not enough to count and I suspect the transporter isn't too bad as the only real current draw is the tube filaments. It's the amps of course that are sucking a lot. So if each Atma-Sphere is 500W and the Pass clone is drawing 200W the total is 1200 which at 120V is 10 amps.

A 15A circuit likely uses 14GA wire and a 100ft run would drop about 6V with a 10A load and of course yours is much higher. My guess is a poor connection in the branch circuit. Often the outlets are daisy chained using the (IMO) crappy push in connections. I've had similar problems and replacing all the outlets in the chain took care of it. $25 well spent at the home center.

A short article on this. http://www.psihq.com/iread/faqvolt.htm

[zybar]

The DCX only consumes a few watts, not enough to count and I suspect the transporter isn't too bad as the only real current draw is the tube filaments. It's the amps of course that are sucking a lot. So if each Atma-Sphere is 500W and the Pass clone is drawing 200W the total is 1200 which at 120V is 10 amps.

A 15A circuit likely uses 14GA wire and a 100ft run would drop about 6V with a 10A load and of course yours is much higher. My guess is a poor connection in the branch circuit. Often the outlets are daisy chained using the (IMO) crappy push in connections. I've had similar problems and replacing all the outlets in the chain took care of it. $25 well spent at the home center.

A short article on this. http://www.psihq.com/iread/faqvolt.htm

Thanks Mike.

George

[Vinnie R.]

Hi George,

acwd1950 and mgalusha are correct.

Ohms law:  Voltage drop = Current x Resistance in the path.  If you are drawing around 10amps (a hefty amount of current) and have too much resistance (long wiring from your breaker, wiring that is insufficient in gauge, or most likely a bad connection to the breaker and/or to the outlet), that is all it will take to get a voltage drop like you are seeing. 

With all your equipment ON, check the voltage at the outlet AND check it at the dedicated circuit breaker.  If the voltage at the breaker is the higher voltage (like the voltage you see at the outlet when the equipment is OFF), you know the problem is a bad connection and/or long wiring/insufficient wire gauge.

Check to make sure all the connections in the path are clean (free of oxidation) and tight. 

Good luck,

Vinnie

[richidoo]

When your gear is on, the other outlets in the house stay high? Then it is just that stereo circuit. I they go low too, call electrician to check the service panel/meter, etc.

If it is a shared circuit, check the connections at each upstream outlet with the stereo running, moving all the way back to the panel until you find high again. Then you're getting warm and can take things apart to find the problem. It is usually obvious, burnt, hot, disconnected, whatever. If stays low on all outlets, check the hot coming out of the breaker, you will have to open the panel.  If breaker's low heck the service which is probably fine, meaning you have a bad breaker - rare.

Usually it is a bad connection somewhere upstream, especially if you are back stabber outlets upstream. Such problems are typical of new construction these days. My house is 3 years old, I have have fixed 4 by myself and hired electricians to find 2 more I couldn't find. I am still horrified by what I find, but not surprised anymore.

[cryoparts]

Good advice below!   

Peace,

Lee

Often the outlets are daisy chained using the (IMO) crappy push in connections. I've had similar problems and replacing all the outlets in the chain took care of it. $25 well spent at the home center.

[mgalusha]

especially if you are back stabber outlets upstream.

I don't know if that's the official name for those but it's certainly the *right* name.

[zybar]

Ok guys, I did some more measurements and I think it reinforces what was suggested:

In the music room (on its own circuit):

The outlets measure roughly 117 volts with nothing turned on.

The outlets measure roughly 108 volts with all the gear turned on.

In an adjacent room (on its own circuit, but next to the music room on the wall panel):

The outlets measure roughly 117 volts with nothing turned on.

The outlets measure roughly 116 volts with all the gear turned on.

As I move further away from the music room, but closer to the panel, the measurements get better:

The outlets measure roughly 118 volts with nothing turned on.

The outlets measure roughly 117 volts with all the gear turned on.


I will replace all five outlets in my music room and re-test to see if that helps and let you guys know.

BTW, should I contact my electricity provider and ask them to check into why I am not getting 120 volts on any outlet I tested?

Thanks again for your suggestions and comments.

George

[JerryM]

George,
It is absolutely normal to see exactly what you are seeing regarding voltage drop and/or gain. 120 volt is "technically" 120 volt at + or - 10 percent. Thus 110 and 120 volt equipment ratings being the exact same thing. In actuality, that rating means the load can be driven at a 10 percent swing from those numbers. As you are at 108 volts, (120 - 12 volts) your equipment is operating well within its design parameters.
The only way to ensure true 120 volt service at the source is to install what is called a buck boost transformer. It's not too costly, but it's not too pretty, either. These devices are typically used in quality control labs or other testing areas where power is coming from far away switch gear, and other industrial items on the service transformer cause unpredictable and out of range fluctuations.
If you call your electrical provider they will confirm this.
What's going on is normal. Listen at will!! 
Have fun,
Jerry

[acwd1950]

My voltage varies here its as high as 130 and low as 115 but usually runs 123 to 126 on the 120v side. 250 high to 235 low usually runs 240 to 245 on 240v side. And I live in a rural area. And Jerry whats a coffee maler? LOL

Steve

[JerryM]

And Jerry whats a coffee maler? LOL

Steve

Geeze, I knew it was too early to write coherently!!! 

[Frank S.]

George- What I would do is not replace the other outlets on the circuit since you are not using them anyway.  I would  simply remove the existing outlets, strip the wires in the box to get some "fresh" copper, treat it with a contact enhancer, make a nice tight splice, top it off with a wire nut, and bury the connection in the box and then cover the box with a blank plate.  It will look fine.  Just make sure you identify all of the outlets on that circuit.  I would also check the connections at the breaker box (hot, neutral, ground), install a brand new breaker, and if there is enough flexibility in the branch circuit wiring at the panel, move your "dedicated" audio circuit to the top position on the buss bars, just below the mains.

[Speedskater]

For power line testing, I use a little "Kill-a-Watt" meter and a oil-filled 1500 watt space heater. The oil-filled space heater is a repeatable and steady load. If you are good at Ohm's Law, you can measure your power lines source impedance.

[PSP]

I am not an electrician, so take this with a grain of salt.

But... if I saw a voltage drop that large when applying the load (turning on your equipment), I would worry that there might be a poor connection somewhere between the breaker and the outlet.  In the worst case (again, I'm not an electrician) I would wonder if there might also be a fire hazard.  For example, when I use an old extension cord with poor connectors, sometimes the connectors get warm... and then I replace the connectors.

Do you have an electrician friend that you could discuss this with?

Just my 1/2 cents worth...

Good luck,
Peter

[zybar]

I have an electrician coming over tomorrow morning.

I replaced all the outlets and did see some improvement (about 3-4 volts), but nothing was noticeably broken or hanging by a thread.

George

[Bob in St. Louis]

move your "dedicated" audio circuit to the top position on the buss bars, just below the mains.

Interesting, I never thought about that Frank.
I also assume, that a good portion of dedicated Audio/Home Theater rooms are after-thoughts in relation to the house being built. So therefore most guys simply add on to the next available breaker that's open and unused and that's most likely towards the bottom of the box.
I only had two open holes in the box remaining and of course they're the bottom two on the same side and have noticed the same problem George is having, just to a worse degree since (being a home theater) I've got a lot more goodies plugged in. 

If a fellow is going to rearrange the wiring in his box, I assume he should use circuits on opposite sides of the box as opposed to all on one side?

Thanks for adding to my "to do" list guys. 

Bob