Would an 12v to 240v inverter run an amp? - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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
Reply
 
Thread Tools Search this Thread
Old 22nd March 2013, 09:30 AM   #1
diyAudio Member
 
Join Date: Aug 2003
Location: Cheltenham
Default Would an 12v to 240v inverter run an amp?

Quick question for you electronic gurus.
I'd like to take some ground-plane measurements of my speaker and i'd also like to use my Onix oa21 (50w channel) amp because I spent a while calibrating it in Lspcad.

Would one of those cheap eBay inverters, hooked up to the car battery have enough grunt to power my amp? The amp is only used in short bursts of a few seconds to get a measurement.
  Reply With Quote
Old 22nd March 2013, 09:35 AM   #2
Bone is offline Bone  United Kingdom
diyAudio Member
 
Join Date: Jun 2004
Location: Dorset, UK
You wouldnt need one that big to run a 50w stereo amp. A 200w one would probably be sufficient.
  Reply With Quote
Old 22nd March 2013, 10:20 AM   #3
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
I do like the cigarette lighter plug to power a 1500Watt invertor. 10Amps at 12Volts is a little bit less than 1500Watts. It is 120Watts!
  Reply With Quote
Old 22nd March 2013, 10:28 AM   #4
diyAudio Member
 
Saturnus's Avatar
 
Join Date: Jun 2005
Location: Copenhagen, Denmark
Please note that efficiency when running an amp on an inverter is far less than the inverters maximum efficiency as the average music signal has only about 10% of it's peak output.

Also note that many inverters are not built to handle variable loads like an amplifier but meant to be used with a reasonably stable load.
  Reply With Quote
Old 23rd March 2013, 12:11 AM   #5
diyAudio Member
 
Join Date: Aug 2003
Location: Cheltenham
Quote:
Originally Posted by Saturnus View Post
Please note that efficiency when running an amp on an inverter is far less than the inverters maximum efficiency as the average music signal has only about 10% of it's peak output.

Also note that many inverters are not built to handle variable loads like an amplifier but meant to be used with a reasonably stable load.
Oh, well
  Reply With Quote
Old 23rd March 2013, 01:58 AM   #6
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
The efficiency only goes down because idle losses start dominating when the power output decreases. For ground plane measurements outside I cannot see you needing any more than 5 watts of clean power, let alone 50, or however more, even a small inverter should be able to power an amp to deliver power like that.

The other option is to buy a small class D amplifier from one of the ebay sellers that are designed to work from single supply rails at low powers and power it directly from the cigarette lighter. The only thing to watch out for there is that the class D output will be bridged and not referenced to ground, so two channel measurements would be out of the question.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  Reply With Quote
Old 23rd March 2013, 02:15 AM   #7
JMFahey is offline JMFahey  Argentina
diyAudio Member
 
JMFahey's Avatar
 
Join Date: Mar 2009
Location: Buenos Aires - Argentina
That inverter probably will be enough for your 50+50W amplifier and some light extra load (Notebook, mic preamp, etc.)
Wouldn't trust it for much more than that.
  Reply With Quote
Old 23rd March 2013, 02:35 PM   #8
diyAudio Member
 
Join Date: Aug 2003
Location: Cheltenham
Quote:
Originally Posted by 5th element View Post
The efficiency only goes down because idle losses start dominating when the power output decreases. For ground plane measurements outside I cannot see you needing any more than 5 watts of clean power, let alone 50, or however more, even a small inverter should be able to power an amp to deliver power like that.

The other option is to buy a small class D amplifier from one of the ebay sellers that are designed to work from single supply rails at low powers and power it directly from the cigarette lighter. The only thing to watch out for there is that the class D output will be bridged and not referenced to ground, so two channel measurements would be out of the question.
I tried to use my Muse M20 EX2
but I couldn't get the SPL high enough to get a measurement. I had the same problem with a 20w channel, Teac micro system.

When taking measurements I have the volume knob of my Onix in the 12 o'clock position, so quite loud really. Don't know how many watts it would be pushing out though.
  Reply With Quote
Old 23rd March 2013, 02:38 PM   #9
diyAudio Member
 
Join Date: Aug 2003
Location: Cheltenham
Quote:
Originally Posted by JMFahey View Post
That inverter probably will be enough for your 50+50W amplifier and some light extra load (Notebook, mic preamp, etc.)
Wouldn't trust it for much more than that.
I can run the laptop off the battery (lasts about 4 hours) and the M-audio mobile pre/mic preamp runs off the laptop USB, so it would only be the amp that need power.
  Reply With Quote
Old 23rd March 2013, 08:45 PM   #10
JMFahey is offline JMFahey  Argentina
diyAudio Member
 
JMFahey's Avatar
 
Join Date: Mar 2009
Location: Buenos Aires - Argentina
Quote:
but I couldn't get the SPL high enough to get a measurement.
I find this amazing, "standard" SPL measurement and speaker curves are made using 1 W RMS !!!

Any bridged car type amplifier fed straight 12V will give you up to 8W RMS at 8 ohms, ample measuring power.

Please describe your setup, there must be something wrong.

And, sorry, but you can't just say:
Quote:
When taking measurements I have the volume knob of my Onix in the 12 o'clock position, so quite loud really. Don't know how many watts it would be pushing out though.


That is not a "measurement" to begin with.
And any curve under such conditions is meaningless.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
12v smps inverter mineralman Car Audio 0 7th February 2011 05:30 PM
chip amp with 12v DC AND 240v AC power supplies? Vital AV Chip Amps 19 15th November 2009 10:39 PM
blown 12v to 240v inverter help bowdown Power Supplies 4 24th November 2005 11:38 AM
12v - 240v 25Amp Transformer Kit F/S! swin1 Swap Meet 4 26th August 2004 06:40 AM
12v Conversion For 240v Equipment 2412electrics Everything Else 1 17th August 2002 09:51 PM


New To Site? Need Help?

All times are GMT. The time now is 02:28 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2