LPA-1 @ 240 Volt Supply???

[theophile]

I spoke with Lonnie @ Emo on Friday (11th) and he says the LPA-1 with a 240volt A\C feed (amp senses and selects automatically !) has a greater amount of additional headroom and reserve (Noticeable if you tend to push the potential of the amp when driving 4 ohm loads)!

Since I'm running a separate circuit for this amp, it would be easy to run a 20A double pole breaker with 10ga\3 wire for this dedicated service! Another benefit would be my Axiom EP500 subs can be configured for 240v operation...so at 2850 watts total power on a 240V service, MAX amperage pushing the system would be only 12 amps! This could also reduce my "electric bill"! Yea, I know...wishful thinking!

Has anyone else tried this higher voltage power arrangement yet! Have you also found this creates more reserve in the LPA-1's operation...Curious?

Ted

[The Administrator]

Fascinating....

I'd love to see the look on your electrician's face when you tell him you need a 220V outlet behind your AV rack for an amplifier.

I have no ideas, but let us know how it goes if you try it!

[gonk]

You mean the amp's power supply automatically chooses between 120V and 220V? I've never heard of a piece of equipment doing that, and in my business we learn to be very conscious of a piece of equipment's operating voltage. There are two LED's on the rear panel which appear to serve as an indicator of the voltage being received, though, so I don't doubt that Lonnie's correct about the way it works. The amps in your Axiom EP500's have a device that has to be popped out and flipped over to change from 120V to 220V operation, which is the typical manner of handling this sort of thing. I wonder why they decided to make it auto-sensing?

Your electric bill would not benefit from driving amps and a sub at 220V instead of 120V because the metering is at a single point and is based in overall consumption - whether you draw 10A at 220V or 18.3A at 120V, your meter sees the same VA consumption and bills you accordingly. Remember - utility consumption rates are generally handled in kWh (kilowatt-hours), not amp-hours. Higher voltages are used because the corresponding drop in current draw allows smaller wire sizes to be used, thus saving first cost.

[theophile]

gonk said:

Your electric bill would not benefit from driving amps and a sub at 220V instead of 120V because the metering is at a single point and is based in overall consumption - whether you draw 10A at 220V or 18.3A at 120V, your meter sees the same VA consumption and bills you accordingly. Remember - utility consumption rates are generally handled in kWh (kilowatt-hours), not amp-hours. Higher voltages are used because the corresponding drop in current draw allows smaller wire sizes to be used, thus saving first cost.

Thanks for the clarification, Gonk! I understand now that higher voltage (220-240) only splits the current draw between the two hot leads of the single 3-wire feed, reducing the need for heavier gauge wire. Alas, no electric usage savings (wishful thinking)!

Have to weigh the possible benefits, though, as a 220 receptacle will either require an adapter plug or a change to the eq. manf. a\c plug configuration! In the end, may be more trouble than it is worth.

Heck I'll probably just run an independent 120volt (my power supply-steady) 30amp\10ga. circuit...that should handle up to 3600w surges w\o too much voltage drop!?

Ted

[gonk]

I would not recommend spending the money for a 30A/120V circuit to power an amplifier, both because I think it's going to be a waste of your money and because I start to worry about the safety and code-worthiness of the arrangement. For one thing, the power supply is designed to operate on a standard 15A residential circuit - putting it on a 30A circuit will gain you current that it can't use, will (if the circuit is installed properly) force you to replace the power cord with a different cord with a 30A plug, and will deprive you of some protection for the amp as the breaker will allow significantly more current to pass than the amp is designed to handle before tripping.

Let's take a step back for a moment and look at the numbers for a minute. Assume 50% efficiency in the amp (half of the input current ends up going to the speakers). Assume that the amp is being run in a six-channel configuration (6x125W) - the maximum rated output is 750W, which assuming that 50% efficiency means 1500W of power being consumed (or about 12.5A at 120V). That puts you right at the point at which a 15A breaker may start to trip. What we just described (assuming that efficiency is realistic, and I can't guarantee that it is - we're into an area where hard data is very difficult to come by) is a nearly impossible scenario. Short of a fairly crazy test tone condition, you are never going to drive all six channels to their rated maximum output simultaneously. Under realistic circumstances, you will use far less current. In my system, a 5x200W amp, two 200W monoblocks, a 32" CRT HDTV, a surround processor, an HD DVR cable box, DVD-R, DVD player, surround processor, and 350W powered sub combined typically draw less than 5A even at reference playback levels according to the meter on my Belkin PF60 power conditioner.

If you are really concerned about feeding the amp all of the current that it can handle, give it a dedicated 15A circuit.

[theophile]

Gonk,

The 2850 watts of A\C use could\would come from one Emo LPA-1 driven hard and long at 1500 watts (as you said, not likely) and 2- Axiom EP500 subs pumping out the bass at 675watts each (possible)!

I've not checked on 30 amp service plug configurations, but maybe a more sensible - future headroom cable feed should be a dedicated 20-amp service for just these power amps!?

I'd keep all the line level units (Pre\pro, cable rec., HD-DVD, Blu Ray DVD) on my filtered\surge Monster Power unit!

Ted

[gonk]

If you are worried about powering both an LPA-1 and a pair of EP500's and want to be 100% assured of never ever getting close to running out of current capacity, I'd run two 15A circuits and not a single 30A circuit. In reality, though, the only time that you will consume that much power is if you are trying to demolish your home, your speakers, and your eardrums all at once with some bizarre full-bandwidth, all-channels-driven, reference-level test tones.

[The Administrator]

All of my AV gear runs through my Belkin PF60, and so I can monitor how many amps it's all pulling.

A movie playing at what I would consider reference+ levels, that is to say, exceeding 100db with LFE effects pushing 110db+, or in other words at ear-splitting volumes with things like cannon fire pounding you in the chest, I have never seen my entire rack pull more than 8.5-9 amps for any length of time. I may have seen it briefly flash to 10 amps. It's usually humming along at about 5-6 amps, under normal TV/DVD viewing.

That's a 36" CRT TV, Pioneer AVR, DVD player, LPA-1, a Dish Network DVR (that always seems to pull .6 amps), and SVS PCI+20-39 sub with its internal 525 watt amp.

As gonk says, the power usage-to-sound level relationship is exponential. Even at fairly loud volume, you're not going to be using more than a few watts. The only times you will approach the 'max' wattage levels are during extremely brief peaks (think LFE effect of a bomb explosion or something), or if you're intentionally trying to melt your equipment.

[theophile]

gonk said:

If you are worried about powering both an LPA-1 and a pair of EP500's and want to be 100% assured of never ever getting close to running out of current capacity, I'd run two 15A circuits and not a single 30A circuit. In reality, though, the only time that you will consume that much power is if you are trying to demolish your home, your speakers, and your eardrums all at once with some bizarre full-bandwidth, all-channels-driven, reference-level test tones.

Thanks Gonk and Admin for more info! I went down to Lowe's and got the run down on our local codes...anything over 20A service would require special receptacles and plugs...not going there!! Yes, if I decide to feed these 3 amps with separate A\C cable, creating 2-15A circuits, as you suggest Gonk, makes the most sense!

BTW, I've been looking at the Belkin PureAV PF60 power\surge\filter unit. How do you like this for noise-surge protection? Is it comparable to the Monster Power ones (aka"MP3600 MKII")?

Ted

[The Administrator]

If you're going to get a PF60, take a look at eCost. They have them for like $150. Much better than the MSRP of $800 or whatever it is these days.

I like mine. It looks cool and provides a very easy way to power everything. The various timed triggers are pretty neat too. Very high 'bling' factor. I've never had a surge protector/conditioner of this caliber, so I can't compare it to anything.

As to sonic benefits, the only affect is that before I would occasionally hear a quiet snap or pop in my system when a heavy-current appliance would fire up (AC, Dryer, etc), and I don't hear that anymore. I also had to readjust the brightness and contrast a bit after installing it - it kicked the brightness up a notch on the TV. Don't ask me how, but it did.

[nilescrane]

The PF60's at Ecost are refurbished. You can find brand new PF60's on other sites. I have the PF40 myself, it's a great unit. I still can't figure out what it really does, but it looks very good.

[madscientist]

Just throwing in my 0.2 cents here.

If you are going to use a power conditioner/ surge protector for the processors and sources, then that will be fine, but I would not recommend that you use it on the amp. It will limit the peak current capabilities of the amp and can cause the main transformer to run hotter than normal which will shorten the life of the unit. All of the units from Emo have built in power conditioning and surge protection which is designed to work with the equipment.

Just my 0.2 cents.

[theophile]

Talk about stepping back to punt (so to speak), I now have my LPA-1, and ALL of my HT equipment being powered through a line conditioner that is run off 1- 20 amp 120v service.

Had to try it this way to see what the "REAL WORLD" is like and came away pleasantly surprised, as you can see here:

emotiva.proboards59.com/index.cgi?board=general&action=display&thread=1180644794

Thanks to Admin, Gonk and all for the great input and suggestions...kept me from going overboard with an idea that really had no substance or need for concern!

Ted