Inverter as a power source

orac02 · 15th March 2006, 09:09 PM

Hi
Has anyone out there tried using a DC to AC inverter for the input to thier system?

I recently designed one at work for a customer, to supply a pure sine wave at 230VAC running from a battery. This was supposedly to improve on main bourne noise.

I took it home and ran my CD and amp from it expecting no difference, at least nothing positive.

Much to my supprise there was a distinct improvement, Sound stage, bass and overall clarity.

Has anyone else got any experiences or thoughts?

One thing i have established so far is it sounds bet(probably) with a large battrey. But still better than the mains with a 17 Ah one

Cheers

Steve

Eva · 15th March 2006, 09:36 PM

Have you tried it in a blind test where you have to guess which power source is being employed from what you listen and without previously knowing it?

p.s: It's sad to see engineers entering the subjectivist field.

N-Channel · 16th March 2006, 02:50 AM

Eva,

Perhaps Steve is convinced that it sounds better because of the absence of line noise often found on conventional AC mains.

However, I would be suprised if there wasn't any noise on the output from FRI generated from the DC-DC step-up section.

(The Other) Steve

Eva · 16th March 2006, 03:08 AM

I said that because I have been considering such a sine-output inverter design recently and there are a lot of chances to generate gentle RFI with such a circuit. Note that the most harmless part is the DC-DC converter, since the output PWM section is a high voltage class-D amplifier that is forced to perform hard switching of 200V to 400V over a *conducting* diode in each clock cycle

(If two phases are used to obtain 230V AC, then hard switching happens twice in each cycle)

The output filter of such converters is also quite a can of worms, because you have to chose between either really bulky output inductors and capacitors, or living with a few volts and amperes of output ripple current and voltage at the switching frequency.

He must have certainly designed a really damn great converter if he thinks that its output contains less non-50Hz harmful stuff than any mains line.

sagarverma · 16th March 2006, 03:23 AM

Steve,

there is nothing to justify what u experienced except saying that it is your perception or like that''what u wanna hear''.

please subject yourself to a blind test.

SAGAR

N-Channel · 16th March 2006, 03:31 AM

OOPS! I meant RFI, not FRI. It's getting late here in Michigan. Gonna go to sleep now......

orac02 · 16th March 2006, 08:22 PM

Hi
Not that I consider it to be an obvious advantage fron the point of view of unwanted noise, but the inverter switches the 12v to produce the sine wave and is then stepped up through a (relatively) standard toroidal transformer to produce the 230v .Not as Eva suggested it might be done.

Secondly, you are absolutely right , at the moment there is a measurable ripple volltage at the switching frequency present on the ac output. (improvable)

So I expected it to be dreadful as a source for an audio system. Thats why we hadnt bothered putting it in a case (then).

I was still working on the principal of "I dont think this will work but if someone wants to buy it........."

The difference to me seemed large enough to accept the "wot no blind test" to see if anyone else had any ACTUAL experiences.

Off to set up a blind test..!

Cheers
Steve

orac02 · 17th March 2006, 10:49 AM

Hi
How about this idea.

Although there is some residual switching frequency ripple on the output this is at a fairly low frequency, the unit is switcing at about 15Khz. At this sort of frequency the input electrolytic capacitors of the amplifier (for instace) will filter it out, as they do the 50Hz ripple.

But

The impedance between the power source (battery) and load
compared with
the impedance between the power source(power station) and the load.
must be less, especially with increasing frequency.

This surely cant be a bad thing!

Thoughts?

Steve

lagoausente · 28th December 2006, 05:11 PM

Quote:

I was still working on the principal of "I dont think this will work but if someone wants to buy it........."

Do you sell it?

KISS · 3rd January 2007, 07:55 PM

It doesn't have to be an inverter.

I noticed a major improvement in bass if I use a sine wave voltage regulator. I got a used Sorenson that retails for about $800 for $100.

15th March 2006, 09:09 PM	#1
orac02 diyAudio Member Join Date: Jul 2005 Location: Suffolk England	Inverter as a power source Hi Has anyone out there tried using a DC to AC inverter for the input to thier system? I recently designed one at work for a customer, to supply a pure sine wave at 230VAC running from a battery. This was supposedly to improve on main bourne noise. I took it home and ran my CD and amp from it expecting no difference, at least nothing positive. Much to my supprise there was a distinct improvement, Sound stage, bass and overall clarity. Has anyone else got any experiences or thoughts? One thing i have established so far is it sounds bet(probably) with a large battrey. But still better than the mains with a 17 Ah one Cheers Steve

16th March 2006, 03:23 AM	#5
sagarverma diyAudio Member Join Date: Feb 2005 Location: NEW DELHI	Steve, there is nothing to justify what u experienced except saying that it is your perception or like that''what u wanna hear''. please subject yourself to a blind test. SAGAR __________________ Never Underestimate The Bandwidth of A Station Wagon Full Of Magnetic Tapes Hurtling Down The Highway...................Andrew S Tanenbaum

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
About a PWM power inverter	gaetan8888	Power Supplies	7	30th May 2012 05:15 PM
Power Inverter help	lljohnll	Power Supplies	14	16th December 2009 05:44 AM
power inverter	rtill	Everything Else	1	27th February 2009 11:15 AM
power inverter	Kelloggrice	Parts	1	8th June 2007 07:44 PM
Current source inverter	Kenshin	Class D	5	30th August 2005 11:29 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

15th March 2006, 09:36 PM	#2
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	Have you tried it in a blind test where you have to guess which power source is being employed from what you listen and without previously knowing it? p.s: It's sad to see engineers entering the subjectivist field.

16th March 2006, 02:50 AM	#3
N-Channel diyAudio Member Join Date: Mar 2003 Location: Sol System	Eva, Perhaps Steve is convinced that it sounds better because of the absence of line noise often found on conventional AC mains. However, I would be suprised if there wasn't any noise on the output from FRI generated from the DC-DC step-up section. (The Other) Steve

16th March 2006, 03:08 AM	#4
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	I said that because I have been considering such a sine-output inverter design recently and there are a lot of chances to generate gentle RFI with such a circuit. Note that the most harmless part is the DC-DC converter, since the output PWM section is a high voltage class-D amplifier that is forced to perform hard switching of 200V to 400V over a conducting diode in each clock cycle (If two phases are used to obtain 230V AC, then hard switching happens twice in each cycle) The output filter of such converters is also quite a can of worms, because you have to chose between either really bulky output inductors and capacitors, or living with a few volts and amperes of output ripple current and voltage at the switching frequency. He must have certainly designed a really damn great converter if he thinks that its output contains less non-50Hz harmful stuff than any mains line.

16th March 2006, 03:31 AM	#6
N-Channel diyAudio Member Join Date: Mar 2003 Location: Sol System	OOPS! I meant RFI, not FRI. It's getting late here in Michigan. Gonna go to sleep now......

16th March 2006, 08:22 PM	#7
orac02 diyAudio Member Join Date: Jul 2005 Location: Suffolk England	Hi Not that I consider it to be an obvious advantage fron the point of view of unwanted noise, but the inverter switches the 12v to produce the sine wave and is then stepped up through a (relatively) standard toroidal transformer to produce the 230v .Not as Eva suggested it might be done. Secondly, you are absolutely right , at the moment there is a measurable ripple volltage at the switching frequency present on the ac output. (improvable) So I expected it to be dreadful as a source for an audio system. Thats why we hadnt bothered putting it in a case (then). I was still working on the principal of "I dont think this will work but if someone wants to buy it........." The difference to me seemed large enough to accept the "wot no blind test" to see if anyone else had any ACTUAL experiences. Off to set up a blind test..! Cheers Steve

17th March 2006, 10:49 AM	#8
orac02 diyAudio Member Join Date: Jul 2005 Location: Suffolk England	Hi How about this idea. Although there is some residual switching frequency ripple on the output this is at a fairly low frequency, the unit is switcing at about 15Khz. At this sort of frequency the input electrolytic capacitors of the amplifier (for instace) will filter it out, as they do the 50Hz ripple. But The impedance between the power source (battery) and load compared with the impedance between the power source(power station) and the load. must be less, especially with increasing frequency. This surely cant be a bad thing! Thoughts? Steve

3rd January 2007, 07:55 PM	#10
KISS diyAudio Member Join Date: Jan 2007	It doesn't have to be an inverter. I noticed a major improvement in bass if I use a sine wave voltage regulator. I got a used Sorenson that retails for about $800 for $100.