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

iraud200 short story
iraud200 short story
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 3rd January 2016, 10:00 PM   #11
mgshightech is offline mgshightech
diyAudio Member
 
Join Date: Nov 2012
There are 2 versions of the board .. 2 ohm and 4 ohm. The 2 ohm version needs all of these mods, including the extra heat sinks to successfully drive 2 ohms. Once the mods are done, it performs like a beast. The IRFB4227 transistor and the larger inductor are the secrets to the 2 ohm version. Make sure your board has the irfb4227 at birth because swapping out those transistors is a dog. The irfb4227 is rated at something like 40 amps .. the cost for that is a high gate charge, which the 2092 chip can only safely drive if you cap it with the small heat sink you see in one of the images, as well as fix the feedback loop as shown so it doesn't try driving it at 800 khz as the board was designed to do. It will chop the frequency response down from 50 khz spec, but who needs 50 khz? Do these mods exactly as shown, and that board will beat the **** out of a 600 watt driver .. even destroy it. When driving only one channel, I smelled burning voice coil on a 600 watt driver some claimed they had driven up to 900 watts into. (no promises on that 900 watt claim for the driver) I'm talking about a 15 inch driver with 2 inch p-p xmax and 260 ounces of magnet. The power supply is capable of delivering 900 watts into a single channel .. wouldn't ask it to do that for both channels. The board just smiled and lauged and said fun, do it again!! The irfb4227 transistors are mean and beastly. Also, for 2 ohm, make sure your copy of the board is rated for 2 ohm and has the larger inductor on it. .. Someone else got a cheap version of the board only to cry over that. I checked the ratings of those inductors, and at audio frequencies they can handle the current, but at switching frequencies they will over heat .. so .. they have to have the heat sinks to dump the extra heat because they are exposed to the switching frequency. Dump the heat with the sink and they will not saturate. One little issue that I haven't tested yet is that the resistor on the (main crucial) dampening circuit might take a beating if you drive a lot of power above 5 khz. Moving to a 7.5 or 10 watt resistor would put that question mark off of the table. I have only used it so far as a sub-woofer driver.

Last edited by mgshightech; 3rd January 2016 at 10:04 PM.
  Reply With Quote
Old 3rd January 2016, 10:45 PM   #12
mgshightech is offline mgshightech
diyAudio Member
 
Join Date: Nov 2012
"I cannot find IRAUD200"

I never could either .. but it's all over ebay and amazon and ali-express in various versions .. I suspect most if not all of them will not perform until you get the details right. Infineon is showing an iraudamp9 which sports four irfb4227s, is rated at 1700 watts, and has to use a gate driver setup to drive all of the transistors. The most power you can get out of irs2092 without going to an extra gate driver architecture is the iraud200 driving the irfb4227 (just two of them) and using a heat sink to stay cool. .. and not trying to get 800khz like the stock iraud200 circuit is. The iraud200 board was designed for some crazy reason without the standard delay capacitor in the feedback loop. This will cause the transistor gates to draw probably 30% more current. This is not what we want when trying to drive irfb4227 directly with irs2092. Infineon is asking $400 for their quad irfb4227 board. (iraudamp9) Which is an unrealistic price tag since you can get Behringers new 6kw class D amp for around $400. Thing that bothered me about the Behringer amps is that they were unwilling to say that their amp has short circuit protection in the specs as well as some other protections. The iraud200 board is well protected with short circuit protection, overcurrent protection and overtemp protection. Once you get them working.. they should be the proverbial "bullet proof" I am very happy with these two boards ........ finally .... took six months of occasional attention to figure out the right mods.
  Reply With Quote
Old 4th January 2016, 03:18 AM   #13
doctormord is offline doctormord  Germany
diyAudio Member
 
doctormord's Avatar
 
Join Date: Oct 2007
I'd go for the Iraudamp9 copies, the pp gate drivers makes life easier.
  Reply With Quote
Old 4th January 2016, 09:49 PM   #14
voltwide is offline voltwide  Ireland
diyAudio Member
 
Join Date: Jan 2010
Obviously "IRAUD200" is developped by some chinese unknown brand.
So I do not expect it to be a really good design.
Better rely on 1:1 copies of IR-reference designs offered for little money by sure-electronics and others.
  Reply With Quote
Old 5th January 2016, 03:13 AM   #15
mgshightech is offline mgshightech
diyAudio Member
 
Join Date: Nov 2012
You're right about the iraud200 (and iraud350) being some chinese unknown brand, and not being a good design .. works beautifully now though :-) Why couldn't the chinese just get it right the first time? Yaknow that's a really good question that we in the west continue to confront with the Chinese stuff that has no western style quality control management.

the iraudamp9 looks like an interesting option. ebay offers one from ljm (L30D). My earlier exp. with ljm is that the board (L25D) did not perform as claimed by the seller, but that it did perform for 8 ohms. In the case of L30D, it looks like the heat sink is substantially smaller than that of the iraud200, and the inductor will need a heat sink as well, so I doubt it will be safe with 2 ohms out of the box. That board may have a great chance of working with just heat sink boosting though and successfully drive 2 ohms. I doubt he went crazy like the iraud200/350 folks and eliminated the 150pf 1kohm delay in the feedback as his L25D had it there . .. at least I see a small cap on it with the label 151, which is probably 150 pf. The L25D has dampener caps/resistors built in, so I expect ljm would have followed suit for the L30D Sure electronics is probably a good bet. I didn't find a sure electronics option that matched the amp9 or iraud200 though. Parts-express has those, and there is no match. The specs I wanted required either the iraud200 or the amp9 .. either the two transistor or four transistor version of the amp9 would have worked. However LJMs L30D is only two transistors. In any case, I got what I wanted, it just cost way too much time and extra trouble. If I were to propose a solution to the 600-1000 watt per channel 2 ohms and +/- 70 volt power supply at this point I wouldn't know whether to choose the iraud200 and follow these mods or to be bold and try the L30D that I don't know much about. .. Let people decide on their own I suppose.
  Reply With Quote
Old 5th January 2016, 07:36 PM   #16
Th3 uN1Qu3 is offline Th3 uN1Qu3  Romania
diyAudio Member
 
Join Date: Feb 2010
Location: Bucharest
Send a message via Yahoo to Th3 uN1Qu3
Ahh, the marvels of Chinese engineering. I have a similar story for you.

A while back i had a pair of cheap karaoke type active speakers to fix, and after cleaning up the mess that some other tech made of it, i noticed a whistling noise in the speakers, which would come and go depending on the input used, volume level and frequency content.

Something was oscillating, that was obvious. But what... that was not so easy to determine. I checked the amplifier but it did not seem to come from the power amp itself. I then disconnected the tuner (which was replaced by someone else with a module from a Sony stereo), it was better but it still did it sometimes.

Eventually, i traced the problem down not to a faulty part, but to poor design. The supply for the mixer, tuner and all that stuff is made with 7812/7912. Nothing out of the ordinary here. The problem was how they did that.

The regulators were fed by two 100 ohm 3W power resistor from the main filter capacitors. The Chinese guy designing the thing, in his infinite wisdom, thought that because he had the main filter caps there, there was no need for input capacitors to the regulators, but he apparently forgot about the 100 ohm resistors between the caps and the regs... The lack of an adequately low impedance input was causing the 7812 to oscillate, and when a change in power consumption occured, the oscillation would be modulated causing the audible whistle i was hearing in the speakers. Installing some 22uF electrolytic caps between the input and ground pins of the regulators stopped the oscillation and made the speakers sound clean. Well, as clean as some bottom-of-the-barrel chinese sh** can sound, but nevertheless, loads better.

Oh, my story has nothing to do with this board. Sorry for going off-topic.
__________________
"Audio grade" components simply means that they failed at a more critical job.
  Reply With Quote
Old 5th January 2016, 10:01 PM   #17
ChocoHolic is offline ChocoHolic  Germany
diyAudio Member
 
Join Date: Dec 2003
Location: Munich
Quote:
Originally Posted by mgshightech View Post
Why couldn't the chinese just get it right the first time?
You are missing the point. They are getting it exactly right for their customers.
The business model does not need a proper design.
Why boosting R&D costs, as long as there are enough ignorants who buy just anything simply because it is cheap and accept low quality?
Why boosting R&D costs, as long as there are enough DIYers who buy just anything simply because it is cheap and then spend months to improve it according personal needs?
Why boosting R&D costs, as long as there are enough DIYers who buy just anything simply because it is cheap and then deliver R&D hints for free?
  Reply With Quote
Old 6th January 2016, 12:18 AM   #18
voltwide is offline voltwide  Ireland
diyAudio Member
 
Join Date: Jan 2010
Quote:
Originally Posted by ChocoHolic View Post
You are missing the point. They are getting it exactly right for their customers.
The business model does not need a proper design.
Why boosting R&D costs, as long as there are enough ignorants who buy just anything simply because it is cheap and accept low quality?
Why boosting R&D costs, as long as there are enough DIYers who buy just anything simply because it is cheap and then spend months to improve it according personal needs?
Why boosting R&D costs, as long as there are enough DIYers who buy just anything simply because it is cheap and then deliver R&D hints for free?
  Reply With Quote
Old 6th January 2016, 12:41 AM   #19
mgshightech is offline mgshightech
diyAudio Member
 
Join Date: Nov 2012
I shoulda seen that reply comin'
  Reply With Quote
Old 6th January 2016, 10:21 AM   #20
ChocoHolic is offline ChocoHolic  Germany
diyAudio Member
 
Join Date: Dec 2003
Location: Munich
Yup, but it is not necessarily a bad thing.
Business company and customers seem to be satisfied. What else could one demand?
Only some old fashioned dinosaurs like me do not enjoy this way, but they do not need to buy it.
Publishing learnings for free also is not a bad thing. It is just a personal question whether you feel that it will be used more in a way which you support or more in a way which you do not want to support. Unfortunately this is often difficult to judge and even more difficult to control.
Sorry for off topic discussion. Must stop now, don't want to violate forum rules.
  Reply With Quote

Reply


iraud200 short storyHide 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
Iraud200 mgshightech Class D 57 2nd January 2016 11:51 PM
Blown power tube - a short story 50AE Tubes / Valves 4 25th December 2011 07:00 PM
Does anyone know the name of this story? johngalt47 The Lounge 2 7th September 2010 11:29 PM
My story Dj BASS AMP Introductions 14 16th March 2003 10:43 AM


New To Site? Need Help?

All times are GMT. The time now is 12:46 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki