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Old 7th November 2012, 01:17 PM   #361
dvisves is offline dvisves  United States
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Default testing Class D amplifiers

I have ruined two Class d modules by testing them in the conventional way.I attached the signal generator to the input and loaded the module with a wirewound 50 watt resistance of 8 ohms.I used a compuper based oscilloscope to monitor the out put waveform.As i increased the input signal the heatsink got very very hot and the module stopped working.

I need to explain the reason why i started testing the class d module.There was inconsistency in the advertisements for the amplifier module.The ads said 100watts rms at 4 ohms.Assuming that the the Class D has an efficiency of 85% which is typical,the heatsink would have to dissipate 15watts per channel and total 30 watts for stereo.The heatsink attached to the module was tiny and could not dissipate 30watts by no stretch of imagination.Hence my experiment to determine the true rating of the amplifier.
Can any body point me in the right direction.
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Old 7th November 2012, 01:22 PM   #362
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Quote:
Originally Posted by chaparK View Post
Na, double precision is my very own prerogative
As the programmer, I'm the one who's deciding when it's required to switch to double precision. So this "switching" happens in the code and is not user selectable.

One less thing you need to worry about
Ok, thanks
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Old 7th November 2012, 07:10 PM   #363
chaparK is offline chaparK  Luxembourg
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Good news: I managed to convince one of the very best wxWidgets experts to work with me on the control application!

Xavier actually joined the team about a month ago and wrote already many lines of great code. He also set up a SVN server so that we can easily exchange updates and keep track of the changes.

He's now a member of this forum so you might read his posts here some day

Last edited by chaparK; 7th November 2012 at 07:17 PM.
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Old 9th November 2012, 01:32 PM   #364
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Good thing that you are getting some help, should take some load of your shoulders
Could you give us an example of when you would activate the "double precision mode" ?
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Old 12th November 2012, 05:24 AM   #365
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Just ordered all external parts, this remote was one of them. Didn't find any other really small one.

Click the image to open in full size.

I'm hoping to be able to put things together over christmas
Any chance of that happening ?
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Old 12th November 2012, 08:52 AM   #366
Ryssen is offline Ryssen  Sweden
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I to ordered some parts,but I`m planning to use my Logitech harmony remote.What remote should it be programmed as?
And what pushbuttons to use?
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Old 12th November 2012, 09:54 AM   #367
chaparK is offline chaparK  Luxembourg
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Quote:
Originally Posted by dahlberg View Post
Could you give us an example of when you would activate the "double precision mode" ?
Filters in the lower frequency range is typically the place where you want to use double precision.

Quote:
Originally Posted by dahlberg View Post
Just ordered all external parts, this remote was one of them. Didn't find any other really small one.
This remote should be fine. I just had a quick look and, well, if you need a really small remote...

More seriously, I like these ones:
- Cute one
- Small key ring
- More keys / more options
- Big mute button


Quote:
Originally Posted by dahlberg
I'm hoping to be able to put things together over christmas
Any chance of that happening ?
Definitely!
I'm expecting the production sample some time next week. Then the remaining units would follow shortly after.

Quote:
Originally Posted by Ryssen View Post
I to ordered some parts,but I`m planning to use my Logitech harmony remote.What remote should it be programmed as?
And what pushbuttons to use?
The board currently supports NEC and JVC protocols. Any layout using one of these protocols is compatible.

After choosing your controller model, the next step is the 'learn' feature of the board that lets you associate a key of you controller with a function.

Supported functions are:
- On/Off
- Mute
- Volume +/-
- Preset +/-
- Preset 1, 2, ..., 9
- Source select
- Balance L/R
- Bass +/-
- Treble +/-
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Old 18th November 2012, 07:44 PM   #368
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Well I got me 2 x Behringer ultradrive pros to play with.
Dead easy to set up and it performs quite well.
I was able to try my Lazy ribbon tweeters at a lower freq than before so easily and that gave a good SQ improvement.

So, I am sold on the flexibility and usability of this sort of thing.

I have found ditching the passive gave some nice benefits in bass immediacy. I can run steeper slopes on the Tapped horns and mid bass horns. As my system is time aligned i find L-R 12 slopes on the rest to sound the best at present - more fiddling no doubt to come.

I read up on tests Behringer VS miniDSP, where some preferred the mini and some could not tell the difference...

I think there are definitely ADC / DAC issues with the Behringer, though the ditching of passives has given a win back I think there is more to come from my system if I could get the best of both worlds - Great ADC and great DACs.

How is the project going - I am very keen to try a digit / analogue in and 10 out solution
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Old 19th November 2012, 08:01 PM   #369
Ryssen is offline Ryssen  Sweden
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Hows it going with programming?
Could we maybe get a list of what feauters it contains?
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Old 19th November 2012, 09:57 PM   #370
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I'm actually looking forward to the final presentation, can't be that far away
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