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.
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.
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 😉
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 😉
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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" ?
Could you give us an example of when you would activate the "double precision mode" ?
Just ordered all external parts, this remote was one of them. Didn't find any other really small one.
I'm hoping to be able to put things together over christmas
Any chance of that happening ? 🙂
I'm hoping to be able to put things together over christmas
Any chance of that happening ? 🙂
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?
And what pushbuttons to use?
Filters in the lower frequency range is typically the place where you want to use double precision.
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
dahlberg said: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.
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 +/-
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😉
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😉
I'm actually looking forward to the final presentation, can't be that far away😎
I'll start posting details of the final board next week - including pics, as the boards are now being manufactured 😉
Excellent
Christmas FIR is just what I want this year well maybe with a new ViewSonic VP2770 too...
Best regards from France
Jean-Claude Gaertner
Would it be possible to use this push buttons?
4x4 Keypad[MCU Accessory board matrix keyboard buttons] | eBay
4x4 Keypad[MCU Accessory board matrix keyboard buttons] | eBay
No that's not ideal, there are too many buttons and I can't see how they're wired to 8 output pins.
I recommend placing 5 buttons in a cross-pattern (left/right/up/down/center) for navigating easily through the menu. A 6th button (SET) should lie somewhere near the cross, because it's by pressing this button that you confirm a change made in the menu.
The 2 remaining buttons (StandBy, Mute) can be placed elsewhere, up to you.
Hmm no unfortunately I can't recommend anything off the shelf.
Your options:
1. How about a breadboard?
2. Chassis screw-on buttons?
3. You guys design a simple PCB single-layer for 8 push-buttons 😉 It would come at fairly cheap. That's the option I'd recommend.
I also suggest that you look at the project as a whole - i.e. what chassis do you intend using? Is the power supply going to fit into it? How much height is available for your push-button board? Where are you going to place the LCD? etc
