Here's a useful toy

[brucek]

Hey Guys,

I recently bought a very useful toy that measures and displays voltage, current, real power, power consumption, power costs, max power, max current, etc, etc.

It's a real quick way of determining how much power your HT system uses. It's also handy for lots of other uses around the home when you need to know if you've got a little too much plugged into a receptacle. In the past I have used a breakout AC cord and my meter measuring current to establish the power, but it's slightly dangerous if your not careful, and a bit of a hassle. This device makes it quite easy.

It's also useful to leave plugged in with some system equipment that you leave on all the time where you want to see how much power they draw over a month perhaps. Even when your system is turned off there are lamps etc that leak power. Might be interesting to see what it costs you....

We tend to over estimate the requirements for our stereo systems with our multi 20 amp circuits...... some people may get a bit of a surprise if they bought one of these devices.

For example, I have two 20 amp dedicated circuits for my system. On one side I have 3 Bryston amplifiers, a Bryston processor and a Feedback Destroyer plugged into a controller (with its huge 10-3 cab tire AC cord) which then plugs into a 20 amp receptacle . I could probably arc weld with that cable. The three amplifiers alone as configured are spec'd to supply 1530 watts.

Hook up my new measuring device to this circuit (you just plug it into the wall receptacle and then plug your AC cord into it). :T

Total power dissipated at idle with all 3 amps and processor and BFD turned on ......... 219 watts.
Total power dissipated with normal listening level music....... about 300 watts. And before you say, ya but what about the demands of explosions etc.........well, that comes from your filter capacitors. Safe to say my 20 amp circuit (2400 VA) is suffice.

The other nice feature of this device is that it shows real power (watts) and not volt-amps (VA). As everyone knows, unless a device is purely resistive (i.e. a toaster), then power factor must be taken into consideration. If you plug an amplifier into a 120 volt circuit and it draws 3 amps, then the power in watts dissipated isn't 120 x 3 = 360 watts. The 360 watts is actually volt/amps (360 VA). The real power dissipated in watts is 120 x 3 x PF (power factor).
Power factor is required to be considered as a result of the current lagging the voltage in a device that is not a pure resistance. Boring stuff, but interesting that this device calculates it. No doubt they use a zero crossing measurement to calculate the phase angle to get the power factor, but that is quite acceptable when using a pure sine wave.

So for my amplifiers, the device shows 120 volts, 2.11 amps, 219 watts. If I multiply 120 x 2.11 = 253 VA. So the power factor is 0.87

Here's a picture.
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I bought this thing at Canadian Tire in the electrical department for $24.99. Good toy for a good price....

brucek

[Andrew Pratt]

Cool I'm very interested in buying one of these....I was thinking that it would be nice but I likely couldn't afford it...but $25 is a great price:T

[Brandon B]

Hmm. So my three 20 amp and one 30 amp circuits are just plain silly! Curious what my Crown MA3600 draws driving the sub. Have to hunt for a U.S. equivalent.

BB

[Neal_C]

Not quite as pretty, but this is similar.

[brucek]

Hmm. So my three 20 amp and one 30 amp circuits are just plain silly! Curious what my Crown MA3600 draws driving the sub

Yeah it would be interesting. I believe those are class A, so you'll perhaps have a high idle current. hehehe...never feel silly having too much power..... :T

I see a lot of applications for this thing.

I like the max features, where you can clear the memory and then plug it into your HT system and watch a movie and then unplug the thing and click through and see the stored maximum amount of power and current that was experienced through the movie, so you don't have to sit and watch the darn thing to see how high the power consumption was.

The overload feature is kind of cool too. You can set a current overload value and a power overload value, that will cause the thing to beep and flash if exceeded. So if you had a circuit that you wondered if it was OK for a certain number of pieces of equipment, you could set the overload to say 10 amps and 1200 watts and then leave it hooked up and see if you get an alarm with all different types of music or movies.

You can also enter your kilowatts per hour cost and it will calculate how much it costs to run a device for a certain length of time.

Lots of goofy features - basically I like to know how much power something is dissipating......

brucek

[taz13]

If buying at Crappy Tire Product# 52-8851-2

[David Meek]

Here's the UPM website. They're the makers of Bruce's cool new toy. They have a dealer locator phone number if you are interested. I am. :T

1.888.468.6876

[Patt]

Hey! That's a pretty neat little gadget.

My little laser tool is handy for aligning stereo speakers, etc. too.

[Clive]

Quite cool. Now we'll know for sure.

[Andrew Pratt]

Well for $25 I couldn't pass so I picked one up this afternoon. I haven't installed it yet but maybe I'll get to that later tonight...or more likely tomorrow morning. I'm very interested to see what differences there are between my two power amps

[mitch57]

Where can you get one of these in the US?

[David Meek]

Here's the UPM website. They're the makers of Bruce's cool new toy. They have a dealer locator phone number if you are interested. I am. :T

1.888.468.6876

Look here.

[Andrew Pratt]

I just spent some time playing around with various items in my house to see how many amps they're were each pulling and it was very educational. My toaster and coffee maker each were pulling out between 5 and 7 amps each while the microwave and hair dryier were up near 12! On the HT side both power amps (Rotel RMB 1075 and RM1080 were typically around 1 amp with peaks to 2 amps with heavy continous bass). The sub amp which I thought would be higher typically was fairly low unless I turned up its volume way beyond its calibrated levels. For giggles I also plugged in both power stips that the rest of the AV gear is plugged into and they were both under half an amp. I guess my dual 20 amp lines are likely not in any real danger

[taz13]

So it is worth the $25?

[Brandon B]

Actually, this is really useful info in terms of sizing transformers for the balanced power units Jon and Thomas have been seducing us into in the DIY area. Makes me feel a lot more secure putting 7 duplexes on mine since none of the components will be amplifiers.

BB

[Andrew Pratt]

I'd say yes...I'll be useful for other things too. I was tripping the breaker upstairs and now i know why.

[ajpoe]

so i'm confused... my whole system doesn't use as much power as a toaster? lol

[hidefdvd]

I just spent some time playing around with various items in my house to see how many amps they're were each pulling and it was very educational. My toaster and coffee maker each were pulling out between 5 and 7 amps each while the microwave and hair dryier were up near 12! On the HT side both power amps (Rotel RMB 1075 and RM1080 were typically around 1 amp with peaks to 2 amps with heavy continous bass). The sub amp which I thought would be higher typically was fairly low unless I turned up its volume way beyond its calibrated levels. For giggles I also plugged in both power stips that the rest of the AV gear is plugged into and they were both under half an amp. I guess my dual 20 amp lines are likely not in any real danger

ANd here I spent a crap load more for my Monster AVS2000 to tell me how many amps my setup draws :M. No actually, I got it to for other reasons but I was very suprised that with everything plugged in, my setups draw was under 3A. Only when I watched LOTR did it peak at 4A.

[aud19]

so i'm confused... my whole system doesn't use as much power as a toaster? lol

Well heat requires a lot of amps so I'm not surprised that a toaster would require a few. I guess technology has advanced enough to make modern amps run efficiently and cool enough to not require huge amounts of juice to power them. They store enough power internally for loud peaks and otherwise, especially with powered subwoofers don't need to draw huge amounts of power to pressurize a room....

[Sonnie Parker]

Nice find Ken...

I think I know what I need to know without buying one now. I basically have nothing to worry about.

And to think I had 16 20amp receptacles behind my old stereo cabinet... :roll:

I only have 4 now and plug my Panamax 5100 into one of those and everything else goes into my Panamax.

So if my Panamax is rated at 1800watts... I should be in fine shape running everything into it.

[mitch57]

Good luck trying to find the UPM EM100 model in the US. I even called UPM. She gave me a list of stores to try but none of them carry it. I called UPM back and and she said she would have her US distributor give me a call. He hasn't called me.

I even tried to purchase it through Canadian Tire but they don't ship to the US. I guess I will have to make a trip to BC to get one. I live about 45 miles south of Surrey, BC.

[Kevin P]

Amps store a lot of power to handle transients (peaks), so they don't draw as much power from the wall as you would think they would, given their wattage ratings.

What I am curious about though is how much power the amp draws when it's first powered up, when it has to charge up those huge capacitors in the power supply. I bet they draw 5 or 6 amps each for a second or two. That's a consideration for sizing your circuits to your HT.

[jim777]

Just so it's clear, as with speaker cables, the max rating is the max that a cable can take without melting or whatever. Your 20amp circuit would melt or burn or whatever if you could pass 40amps in it. But note that there will be voltage drops in a cable depending on it's resistance to current, so the bigger the better. Sure that with power outlets (at 120V), it is less critical than with speaker cable (when we power a 4 or 8 ohms speaker), but you can guess that a steady 120V at the input of your components is better than a 100-120V input, even if the wires are not melting in the walls...

[Glen B]

What I am curious about though is how much power the amp draws when it's first powered up, when it has to charge up those huge capacitors in the power supply. I bet they draw 5 or 6 amps each for a second or two. That's a consideration for sizing your circuits to your HT.

To accurately measure amplifier power draw at startup will require an ammeter with inrush current measuring capability, one feature the little power measuring gadget does not appear to have. With regard to circuit sizing, my Sears Craftsman air compressor that operates on a 15A/120V circuit draws a whopping 84 amps :E of inrush current at startup. I think our 15A and 20A circuits are more "resilient" than we give credit for.

[Chris D]

Interesting product. It's always funny to me to see the variety of products you all can buy from a store named "Canadian Tire".

It's like Washington State here--every year (I think it's August or something) there's an annual "car tire and beef" sale at local tire dealerships. The first time I heard it, it blew my mind. People around here just think it's normal, though, and even plan their annual purchases around it to get a good deal.

Weird.

[Patt]

I was trying to think of a place locally that has an odd name. An electronic product from a tire store caught my attention when I first heard about it.

Nothing like a little beef to go along with your new car tires.... :rofl:

[jim777]

Ya, they had to do alot of publicity like "Canadian Tire; not just tires". It's a hardware store, electronics store, car pieces store, anything-you-would-need-around-the-house store :rofl:. Just take a look... http://www.canadiantire.ca

[sprout]

Just in case anyone in the UK fancies one of these then:

Lidls have them a few times a yeaer at £4.99

I too used one of these with fantastic results when speccing to build a 240 to 110V tx to run a US Velodyne DD10 in the UK.

What all the experts were saying was so over the top.