[hometheaterdoc]

Does anyone know of a manufacturer that makes true sine wave instead of simulated sine wave DC-AC inverters?  I'm looking for something to power a preamp... so it doesn't need to be huge wattage output.

Any help would be greatly appreciated.  I've been searching but all I'm finding are inexpensive alternatives that don't do what I want....

[dwk]

Is it really that hard to google for 'pure sine inverter'???

Try here:

http://invertersrus.com/

Pure sine inverters starting at $100 for a 150W unit.

[hometheaterdoc]

Is it really that hard to google for 'pure sine inverter'???

Try here:

http://invertersrus.com/

Pure sine inverters starting at $100 for a 150W unit.

No, it's quite easy to do a google search and come back with several thousand links.  I've done that already several times and waded through hundreds of pages.

I have found several vendors that I've never heard of selling products by manufacturers that I've never heard of before.  A lot of the products have more wattage than I require.  Others look like they would be much too large for what I require.

The reason for the post was more to narrow down the field of choices.  My apologies on any confusion.  I didn't word my initial post well enough.  

I want a true sine wave inverter that is low noise, provides pretty clean power, is reliable and won't butcher the sound.  Since this is for a high end preamp, my hope was that someone had tried a few and had some "audiophile approved" suggestions.  Not that it has to be in a pretty case or cost $5 million dollars.  

I will continue looking.  Thanks for the link.

[dwk]

Ok, guess my response was a bit short.

I've started looking at inverters for power use, but am far from an expert. Quick thoughts

- not many audio folks doing this. Most that are going battery powered are going straight DC
- I'm *guessing* that there won't be too much difference between low-end pure sine units.
- higher powered units may well work better than lower powered units, as they may have lower output impedances, better output stages etc. Remember- these are basically power amps.

Since this is for a 'high end' preamp (I'm guessing tubes, otherwise you'd probably be better off looking at a DC supply), I'm assuming you have at least a few $$$ to experiment with. To me, I think it'd be worth getting one of the 150W jobs, pulling the battery out of the car or something (I'd definately use a big honking car battery or something for this experiment, to ensure battery impedance is not an issue)  and trying it.  In my view, if this doesn't get you VERY close to what you're looking for, the entire effort might be an exercise in frustration

[NealH]

The MGE ultra-isolator is probably all you need.  Here is a link to the model 100.  I have it's predecessor (virtually the same) and you are welcome to  borrow it and see how it does.   I really doubt there is any additional benefit with a sine wave inverter other than a tighter voltage regulation, which our utility is plenty tight enough and, ride through capability, which is only beneficial during power dips and these don't occur that often except maybe during violent T'storms.    

http://www.mgeups.com/products/pdt120/powerc/tpz100/t100.htm

The model 800 power conditioner will work too and, provide a very tight voltage regulation.  But, it will be more expensive and I don't think you need the added regulation.

[hometheaterdoc]

The MGE ultra-isolator is probably all you need.  Here is a link to the model 100.  I have it's predecessor (virtually the same) and you are welcome to  borrow it and see how it does.   I really doubt there is any additional benefit with a sine wave inverter other than a tighter voltage regulation, which our utility is plenty tight enough and, ride through capability, which is only beneficial during power dips and these don't occur that often except maybe during violent T'storms.    

http://www.mgeups.co ...

Neil,

Thanks for the tip... but I'm looking for a 12 Volt DC-AC Inverter because I want to run a Tact room correction preamp in my truck  I've got Butler Audio tube hybrid amps for the front mains and for the sub box.  I spent 6 solid months trying to get good sound in this truck given the mounting limitations for midrange and treble drivers, as well as limitations of the cabin's acoustics.  I went through at least 100 different driver combinations and mounting configurations, dozens of different custom crossover implementations before settling on what is in there now.  I did a pretty darn good job given all the constraints.... but it still is woefully awful compared to my home systems.  Given the success I've had with the Tact room correction in my home systems, I want to implement the same thing in my vehicle, where it will really shine.  I've spoken with Tact about it and they already have a number of customers who have done this very thing.  They've also rigged up displays and are controlling it remotely via RS-232.

If you disconnect the front display panel, the preamp only draws a couple watts of power.  So I don't need a super huge DC-AC inverter.  I just need one that will give me really clean power and not degrade the sound of the Tact anymore than necessary.

[Occam]

....Try here:
http://invertersrus.com/
Pure sine inverters starting at $100 for a 150W unit.

Microwaves heat in normal times TV monitors will be crystal clear (as good as using city power)

Living in NYC, I don't find that very reassuring. But I've no doubts that a couple of well chosen common mode chokes, cmc, and capacitors could address the residual noise quite effectively (or the Corcom hermetically sealed equivalent as used by Equitech for isolating and providing additional filtering for digital components). I've no idea as to the specific components or values.
Felicia might be the bee's knees when fed from the smaller of the referenced inverters.

[nuforce]

If you can wait, look for NuForce's pure sine wave inverter in early 2006. May be we'll demo at CES 2006.  <5 lb, 2000W.

Jason

[Facilitator's warning  Jason - the Lab board is not the appropriate venue for your marketing (especially of vaporware). Feel free to do so in Market Square- Commercial Posts. Your post added absolutely nothing to facilitate understanding of the technical issues regarding the use of inverters, just a plug for a presently non-existant product]

[chadh]

Suppose I have no interest in running real audio components in my car/truck/submarine, is there any reason I'd be interested in using a power inverter (e.g. the forthcoming nuforce one)?

rnhood suggested not (except maybe in thunderstorms).

I know lots of people are really keen on the idea of battery powered components at the moment, which manage to do away with a lot of the problems associated with AC operation.  Why wouldn't one get the same benefits using a DC powered inverter to power regular AC components?  
Is this just because good implementation is difficult or expensive?  Is it hard to manufacture good sine waves?

Oh, and just to prove that I'm ignorant, what does it mean that the inverters "are just basically power amps"?

Chad

[Occam]

Jason, Nuforce....whoever,

Your response has been moved to a more appropriately titled thread named 'piffle'. At my leisure, I will move it to a more appropriate venue, the Intergalactic Waste Bin.
Your response violated both my warning and the intent of the Lab board itself, to share knowledge.
If your obfuscation was due to the SECRET proprietary nature of your products, take your horseshit elsewhere.
If the non responsive nature is due to your being in over your head, please have someone who can respond competently do so.
You make assertions and nothing more.

You are now banned from this Lab forum. All of your future posts Lab board will be moved to the Intergallactic Waste Bin. I've neither the time or inclination to deal with your nonsense.

[Occam]

and for anyone who wants some actual content on inverter technology -
http://www.energychallenge.org/2001reports.htm

[jules]

hometheatredoc,

There are a number of high quality pure sine wave inverters now available both for emegency power supplies and perhaps also as a result of demand for solar enegry/battery home power supplies.

I'm not an expert in the technology behind these things but there are two main types, high speed switching and transformer. The latter are heavier and best suited to situations requiring a big starting load. I use an 1800W Xantrex 24V [12V available] DC to AC high speed switching inverter to power my system and I can report that it is totally reliable and totally hum free. This is clearly more power than you would need but I suspect that some of the cheaper/lower power models aren't quite as sophisticated.

If you are prepared to shop around it is possible to pick one of these up either on special or ssecond hand for a good price.

edit: oh yeah, there's also square wave and modified square wave but these are best forgotten.

jules

[goskers]

This is great to see on this site.  I just finished installing a dcx2496 in my car last week.  I am using a relay driven inverter.  On power-up I was blessed with an assload of hum.  I have never heard so much hum in a system.  I have been told that it is most likely the sine wave inverter and how it is giving me grounding issues.  

     I really hope that someone has done this dc-ac with a car without hum issues.  Help, please.  I have no sound in my car at the moment.  

[jules]

goskers,

reckon this is going to be one of those "try all the options" problems.

The basic test would be to take the whole system [including the battery] out of the car and try connecting it up free from a tin shell. This would at least show you if the inverter itself happens to have a nasty tendancy to hum.

Of course it's possible that the hum is some sort of RF prob.  Does it sound like 50HZ?

I don't know what sort of inverter you are using but you might have a choice about earthing and the proper thing is to go with the instructions. I would think that you could try different combinations of earthing particularly in relation to the power cord but also in relation to the shell [earth post] of the inverter.

jules

[goskers]

Unfortunately Jules, I agree with you that this could be a try a lot of options before something actually works type of deal.  I am going to call a couple places tomorrow to discuss typical hum issues with sine wave inverters.  From a little research it seems as though the exceltech 125 is quite a bit better than the rest of the class.  At around 200$ I think it should be.

[jules]

a couple more thoughts ....

does the inverter itself hum? A decent high speed switching model should be totally silent. [Some of them have a fan and that's worth considering if you want to avoid some background noise. The one I'm using doesn't cut in till above the normal current draw of my amp etc.]

If you have a square wave inverter they don't just hum, they almost buzz and along with that so do transformers and everything else! They sort of work but I understand that the harshness of the signal can be a bit hard on transfomers [please excuse my transformer ignorance Occam   ]

jules