Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Class D Switching Power Amplifiers and Power D/A conversion

Ebay amp - is 500W believable?
Ebay amp - is 500W believable?
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 19th June 2017, 01:00 PM   #1
Circlotron is offline Circlotron  Australia
diyAudio Member
 
Circlotron's Avatar
 
Join Date: Jun 2002
Location: Melbourne, Australia
Default Ebay amp - is 500W believable?

Saw this tiny 500W amp board on Ebay.
IRS2092S 500W Mono Channel Digital Amplifier Module Class D HIFI Power Amp Board | eBay
Are the figures for this general type of amp even believable, or are they a total exaggeration? Thinking of using a pair to drive a pair of 15" subs in relatively small sealed boxes with a Linkwitz transform equaliser. Not to a very high sound level but I expect the overall efficiency will be down the toilet. Also thinking of experimenting with 3 boards as a low voltage 3-phase AC source for driving a motor. Just for fiddling around, nothing practical.

So... is this kind of board worth the trouble?
__________________
Best-ever T/S parameter spreadsheet.
http://www.diyaudio.com/forums/multi...tml#post353269
  Reply With Quote
Old 19th June 2017, 01:58 PM   #2
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
diyAudio Member
 
JonSnell Electronic's Avatar
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
If we look at the spec, they are rated at 380W into 4R load with 10% distortion. I would guess that is PMP so to convert to RMS divide by 1.414 say 260Watt absolute maximum at 10% distortion if you are lucky.
For the price, not bad. Reliability, not convinced!
__________________
Support for Fender, Marshall and all Valve Equipment; Audio Innovations, Audiorama FU29, Quad and Leak. www.jonsnell.co.uk
  Reply With Quote
Old 19th June 2017, 09:31 PM   #3
JohnnyInBris is offline JohnnyInBris  Australia
diyAudio Member
 
Join Date: Sep 2016
I'd suggest checking out these amps....

http://stores.ebay.com.au/sure-hifi/...ub=18214263010

I bought a 2x400W amp for driving subs. The quality is excellent
  Reply With Quote
Old 20th June 2017, 01:10 AM   #4
jeremy777 is offline jeremy777  Italy
diyAudio Member
 
Join Date: Jun 2017
since the IRS2092 is a mosfet driver chip that can operate up to +-100V and with proper circuit matching to its MOSFETS can achieve 0.01% distortion figures, and the end efficiency and power handling is entirely due to the quality of the MOSFETS and inductor, the quoted 380W into 4Ω 0.1% distortion with +-65V power seems quite believable. you could even bridge them and push 760W into 8Ω. If it were me, I would probably upgrade the heatsink, if not the mosfets and the filter inductor, and the power capacitors too ... but then you might as well get the bigger version to start with...

if you're only going to be running for short periods at high levels then it might last a while, but it looks altogether too tiny to be asked to do anything demanding ... but it might be fun finding out!
  Reply With Quote
Old 20th June 2017, 01:48 AM   #5
Circlotron is offline Circlotron  Australia
diyAudio Member
 
Circlotron's Avatar
 
Join Date: Jun 2002
Location: Melbourne, Australia
Okay, I don't know why I didn't see the other power output numbers. My eyes just stuck to the 500W figure. For the price it's so tempting, but if it blows up and takes the speaker out with it then it's not so much of a bargain. Hmmm....
__________________
Best-ever T/S parameter spreadsheet.
http://www.diyaudio.com/forums/multi...tml#post353269
  Reply With Quote
Old 20th June 2017, 05:15 AM   #6
ICG is offline ICG  Germany
diyAudio Member
 
Join Date: Jul 2007
Location: Sound Cloud 9
They give the numbers themselves:

380W ( 65 power 4 ohm speaker, distortion <0.1%)
280W ( 65 power 8 ohm speaker, distortion <0.1%)

That sounds reasonable and is still a lot of power for the buck. And the output inductance looks like it can take enough power too. The majority of cheap amps lack sufficient dimensioned output coils.

@JohnnyInBris: I also bought the 2x400W amp. It sounds very good but it does not reach the stated maximum power either. To take ~20% off of the power specs seems to be much more realistic.
__________________
After all is said and done, usually more is said than done.
  Reply With Quote
Old 20th June 2017, 10:56 AM   #7
doctormord is offline doctormord  Germany
diyAudio Member
 
doctormord's Avatar
 
Join Date: Oct 2007
Quote:
Originally Posted by jeremy777 View Post
the quoted 380W into 4Ω 0.1% distortion with +-65V power seems quite believable. you could even bridge them and push 760W into 8Ω.
Uhm, into 2Ω - no?
  Reply With Quote
Old 20th June 2017, 01:22 PM   #8
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Quote:
Originally Posted by Circlotron View Post
Saw this tiny 500W amp board on Ebay.
IRS2092S 500W Mono Channel Digital Amplifier Module Class D HIFI Power Amp Board | eBay
Are the figures for this general type of amp even believable, or are they a total exaggeration? Thinking of using a pair to drive a pair of 15" subs in relatively small sealed boxes with a Linkwitz transform equaliser. Not to a very high sound level but I expect the overall efficiency will be down the toilet. Also thinking of experimenting with 3 boards as a low voltage 3-phase AC source for driving a motor. Just for fiddling around, nothing practical.

So... is this kind of board worth the trouble?
Class D is not a fully "open" field for mistakes, those Chinese are copying, their sources are application notes from International Rectifier and designs from engineers. The parts they use are mostly surplus, but from known brands.

In the process of developing this tiny module someone discovered that a switching regulator SO-8 IC can be used to obtain the gate drive supply rail for IRS2092, referred to -Vcc, and by the way used those 12V to power a fan, maybe even temperature switched with a transistor and NTC.

Otherwise you are going to find a copy of IRS2092 application circuit recommended by IR, maybe with some tweaks taken from others. The FETs are probably going to be surplus from IR or Fairchild, not the best in thermal efficiency, but there is a fan. Class-D modulation used is not going to be top notch (flat regardless of load), but accurate for experimental LF purposes. Output HF damper is implemented with a SMD resistor, this is not very rugged against HF use, but satisfactory for subs. Do not abuse at trebble freqs.

Overcurrent is probably going to cause shutdown, but since threshold is measured as voltage drop across FETs, higher temperature reduces threshold by as much as 2:1. Basic functions are dictated by the IC used. Description mentions DC protection, which is usually implemented with few transistors and diodes shutting down IRS2092, not going to work if a FET is shorted, for that purpose a relay or PSU shutdown is needed, like in class AB. But overcurrent works as a first defense against overload, and thermal shutdown they mention does that too, so a FET is usually shorted due to probe slip or accident in manipulation, or manufacturing defect, or maybe too fast overheat, only.

So it is a creative implementation of IRS2092 datasheet circuit. And there seem to be dozens of creative implementations like that, but the ones in the other website (sure electronics) are more expensive and maybe harder to reverse engineer.

It's not worse than the various class AB kits that have been sold for ages, like XXI century's BD139/140 and 2N3055s class AB kits. I learned class AB with stuff like that.
__________________
I use to feel like the small child in The Emperor's New Clothes tale

Last edited by Eva; 20th June 2017 at 01:25 PM.
  Reply With Quote
Old 20th June 2017, 03:18 PM   #9
denbret is offline denbret  Canada
diyAudio Member
 
denbret's Avatar
 
Join Date: Mar 2011
Location: St-Jean-Richelieu
Quote:
Originally Posted by Eva View Post
Class D is not a fully "open" field for mistakes, those Chinese are copying, their sources are application notes from International Rectifier and designs from engineers. The parts they use are mostly surplus, but from known brands.

In the process of developing this tiny module someone discovered that a switching regulator SO-8 IC can be used to obtain the gate drive supply rail for IRS2092, referred to -Vcc, and by the way used those 12V to power a fan, maybe even temperature switched with a transistor and NTC.

Otherwise you are going to find a copy of IRS2092 application circuit recommended by IR, maybe with some tweaks taken from others. The FETs are probably going to be surplus from IR or Fairchild, not the best in thermal efficiency, but there is a fan. Class-D modulation used is not going to be top notch (flat regardless of load), but accurate for experimental LF purposes. Output HF damper is implemented with a SMD resistor, this is not very rugged against HF use, but satisfactory for subs. Do not abuse at trebble freqs.

Overcurrent is probably going to cause shutdown, but since threshold is measured as voltage drop across FETs, higher temperature reduces threshold by as much as 2:1. Basic functions are dictated by the IC used. Description mentions DC protection, which is usually implemented with few transistors and diodes shutting down IRS2092, not going to work if a FET is shorted, for that purpose a relay or PSU shutdown is needed, like in class AB. But overcurrent works as a first defense against overload, and thermal shutdown they mention does that too, so a FET is usually shorted due to probe slip or accident in manipulation, or manufacturing defect, or maybe too fast overheat, only.

So it is a creative implementation of IRS2092 datasheet circuit. And there seem to be dozens of creative implementations like that, but the ones in the other website (sure electronics) are more expensive and maybe harder to reverse engineer.

It's not worse than the various class AB kits that have been sold for ages, like XXI century's BD139/140 and 2N3055s class AB kits. I learned class AB with stuff like that.
And why not add a speaker protection? Me for the price I would be tempted to try with HP protection.

Last edited by denbret; 20th June 2017 at 03:23 PM.
  Reply With Quote
Old 20th June 2017, 03:28 PM   #10
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Quote:
Originally Posted by denbret View Post
And why not add a speaker protection? Me for the price I would be tempted to try with HP protection.
Do you know what "a circlotron stage" means in electronics, son? The old way of making a "full bridge" as it is called in modern switching electronics.
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote

Reply


Ebay amp - is 500W believable?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Power Supply for 500W+500W Amplifier Pittbull Power Supplies 24 28th October 2010 11:13 AM
Minebea 500W SMP on Ebay 405man Power Supplies 3 21st November 2009 02:34 PM
Selfoscillating HalfBridge 500W+500W by IR. Interested? deflorator Class D 0 10th October 2004 03:30 PM
6th order bandpass -> 16Hz to 82Hz +/- 0.5dB, is it believable? Circlotron Multi-Way 20 28th October 2002 02:16 PM


New To Site? Need Help?

All times are GMT. The time now is 04:39 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki