how many watts is 1,200 VA

[Mr. Studio S]

This is how much power my onkyo m508 consumes. Recently, I started having trouble getting it to come out of protection mode (orange to green lights). I had the power cord plugged into the onkyo preamp's switched power supply which is rated at 700 watts MAX. I've had it like this for at least ten years. Anyhow, the amp started acting normal once I plugged it in straight to the wall outlet. I'm beginning to think the preamp's switched outlet was starving it for power? However, I have no idea how much is 1,200 VA in watts. Thanks

 

[toxcrusadr]

VA is volts times amps (or volt-amps). If you know your line voltage and the amp draw, you can calculate how many VA the eqpt. actually draws.

This chart is handy:

https://upload.wikimedia.org/wikipedia/commons/7/78/Ohm's_Law_Pie_chart.svg

I believe since P=IxV (or P=IxE in the chart since they call voltage E) that volts times amps is also watts, so 1200VA is 1200W. Someone correct me if I'm wrong.

 

[Ds2000]

Using the industry standard of .6 (found on rapid tables), I get 720. May not be exactly accurate.

 

[toxcrusadr]

Could be a problem with a power relay in the preamp if there is one. I doubt the amp consumes 1200W at idle, that's probably max at full output, so if it's going into protection when you turn it on without even cranking it, it can't be starved for power yet. Something definitely amiss.

 

[restorer-john]

If the power amp indeed works correctly when plugged directly into the wall socket and yet has issues on the preamp switched outlet, I would be simply removing and replacing the switched power relay in the preamp. I am assuming you have the matching preamp? It would likely have a slaved relay specifically for the switched outlets.

10 years of high current surge startups have probably carbonised its contacts, resulting in poor contact and a voltage drop- preventing the amp from coming out of protection. That is unless the relay drive circuitry in the preamp has other issues and isn't switching the relay on hard enough.

 

[sKiZo]

I got 14 ... <G>

Anyway ... I've always figured that the switched outlet is more for the little stuff. I have quite a few items plugged into it, courtesy of a power strip, but they're all low draw. The amps are plugged directly into the wall and get switched on separately.

Speaking of power strips ...

Adds new meaning to the phrase "continuous power strip", don't it? <G>

 

[I LIKE MUSIC]

I had one of those power strips, it was called a Tap A Line.

There is no, one size fits all direct conversion of VA to watts. It depends on the power factor (not always known) of the device being powered by the outlet. That is why VA is used. A device with a high power factor will draw more current because it is a reactive load (harder on the switch and outlet) than the amount of power in watts would indicate.

In simple terms 1200 VA could be 1200 watts if the load is a pure resistive load such as incandescent lighting or it could be 800 watts for a reactive load (in round numbers a power factor of about 0.7 for single phase power, with 1.0 being perfect).

 

[restorer-john]

There's absolutely nothing wrong with using the switched outlet relays in your preamp to power your amplifier. Preamps have the switched outlets for that very reason. As long as the relay, socket, wiring etc is within the ratings of your power amp- just use it.

It's adaptors like this nasty Euro to US thing that cause lots of fires- plastic arsonists they are. Poor spring contacts, poor contact pressure etc.

 

[Ken Boyd]

I used those strips on fish tanks when I was young, but I wouldn't ever use them on my audio gear, they are not very well made.

 

[I LIKE MUSIC]

Note that I said that I had one, it was back in the early 1960s and it was given to me as a gift. It did not stay in service very long. Just long enough to say that I used it and I never left it plugged into the mains unless I was there.

 

[elcoholic]

.85 to .9 pf is a pretty good number. So .85pf x 1200VA = 1020w

 

[whoaru99]

Get a Kill-A-Watt if you want to know.

It will show you watts, VA, and power factor.

 

[Mr. Studio S]

It has been working fine plugged into the wall for about a week. When it started acting funny plugged into the switched power on the onkyo integra p304 it would stay stuck in orange. If i'd turn the amp on and off it would finally come on. Up until this time, the power button to the amp was always "on" and controlled through the power button on the preamp for convince. When I turn the preamp on there is a click noise that comes on before the output light illuminates. This must mean there is a relay inside that could use cleaning as mentioned in a previous post? thanks!

 

[unfairlane]

This is how much power my onkyo m508 consumes. Recently, I started having trouble getting it to come out of protection mode (orange to green lights). I had the power cord plugged into the onkyo preamp's switched power supply which is rated at 700 watts MAX. I've had it like this for at least ten years. Anyhow, the amp started acting normal once I plugged it in straight to the wall outlet. I'm beginning to think the preamp's switched outlet was starving it for power? However, I have no idea how much is 1,200 VA in watts. Thanks

NEVER do this with any bigger poweramp. The outlets on Your pre is there for smaller Components like tuners & cd, poweramps should allways be Connected directly into a wall-outlet, no extension-cords either.
1200va means that the amp 1200w max and even moore when it`s started up from Cold.

 

[biscuithead]

In simple terms 1200 VA could be 1200 watts if the load is a pure resistive load such as incandescent lighting or it could be 800 watts for a reactive load (in round numbers a power factor of about 0.7 for single phase power, with 1.0 being perfect).

I second this.
A piece of equipment with nameplate consumption of 1200VA (1.2KVA) means that you should plug it into a device that is rated for a minimum of 1200 watts. An argument could be made that it should even be plugged into one rated for ~%20 more than that. Considering a typical (15A) home circuit is good for about 1800 watts, your M508 (at full power) could eat more electrons than the average microwave. Plug it directly into the wall, and when you see your room lights dim when you crank it past 50%, be ashamed of your carbon footprint , but be proud that it is equivalent to ~ 1.6 horsepower.

 

[Mr. Studio S]

Thanks guys! Now I guess I need to service the relay/fuse in the pramp.

 

[whoaru99]

The M508 is never going to pull power like a microwave, unless you have it on the bench running test tones at full power.

It could draw high peaks if you have it really cranked up, and perhaps a high peak for a couple AC cycles on power up, but average draw will be a small fraction of 1200VA or 1200 watts.

 

[tom3]

Does the amp have a switched power receptacle on the back? Reverse the deal, use the power amp to turn on the preamp for convenience?

 

[Schurkey]

There's absolutely nothing wrong with using the switched outlet relays in your preamp to power your amplifier. Preamps have the switched outlets for that very reason. As long as the relay, socket, wiring etc is within the ratings of your power amp- just use it.

This is technically true, but when was the last time you saw a power amp that had an input-power-rating that was within the capacity of a preamp or other component's switched outlet? I never have.

Thousands and thousands of years ago, I used a "computer controlled" Sharp cassette deck with an on-board clock and timer system to energize the rest of my stereo system. It was in effect a 120-watt alarm clock using corner horns for speakers. Of course, the switched outlet of the cassette deck couldn't supply enough power for the receiver I was using, so I had to build a relay system that plugged into the cassette deck outlet and a wall outlet--the cassette deck energized the relay through the switched outlet, the relay energized the stereo receiver using power drawn from the wall plug.

 

[restorer-john]

...This is technically true, but when was the last time you saw a power amp that had an input-power-rating that was within the capacity of a preamp or other component's switched outlet? I never have...

Most of the preamps I own have switched capabilities that exceed the nameplate rating of the matching* power amp. I've just confirmed three on my loungeroom floor all exceed the rated matching* power amp consumption (2x Sony and a Yamaha). Not only that, the internal relays are usually 10A or 15A in most relay switched preamps, which exceeds the capability of our power points here.

Back in the 70s, most integrated amps simply slaved the switched outlet through the power switch contacts and the consequent rating was much lower. Ever since remote control preamps, we have seen very capable relay switched outlets on most Japanese gear.

That said, there are sometimes bizarrely low rated switched outlets, even when there is a 10A relay and stout internal wiring to the convenience sockets. I make my own mind up from a technical perspective on the relative capabilities of switched outlets based on the load, switch on surges, whether I want a sequenced (manual) startup or whatever.

(*matching- the amplifier a preamp was generally paired with in catalogues and for sale by a given manufacturer.)