SystemD_2kW, any interest for an open design? - Page 39 - diyAudio
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Class D Switching Power Amplifiers and Power D/A conversion

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Old 3rd April 2013, 10:15 AM   #381
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ChocoHolic if you have time, can you create the control loop diagram of this amplifier for analysis in pspice.
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Old 3rd April 2013, 11:14 AM   #382
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I think building up the actual amp circuit is a more true to reality simulation than using the ideal voltage controlled switches and what not.
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Old 3rd April 2013, 05:16 PM   #383
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Quote:
Originally Posted by Tekko View Post
I think building up the actual amp circuit is a more true to reality simulation than using the ideal voltage controlled switches and what not.
True, but similar you contradicting yourself when you build, use and publish spice models like the circuit simulations you posted in the thread.

non the less I was interested in the loop network analysis its more fun and interesting then trying to live up silicon component behaviour.
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Old 3rd April 2013, 08:03 PM   #384
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Hi Reactance,
as far as it concerns my person the boolean algebra generally delivers 'false', when checking the condition 'if you have time'.

Have a closer look to posting #375.
The LT spice simulation is already using an averaged gain modeling of the switching stage. So simulation times are short.
It can be used for AC analysis and transient analysis.
By offering this file I am disclosing lots of key informations on loop control of class D amps. Everybody can experiment with it and learn step by step.
If you want to translate it into the abstract language of linear control theory - feel free to do so, but you will loose key informations of the interactions between brute circuit non linearities and loop control (each real stage has clipping limitations!!).
Designing a classD amp with postfilter feedback, but without taking into account such fundamental non linearities, will bring you in trouble when stepping from theory to reality.
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Old 8th April 2013, 07:27 PM   #385
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...for better listening I decided to go for a quick&dirty implant in an enclosure, which allows to use the amp in the living room.
You see I have just thrown it into the box for the moment...

In the final build I will put two half bridges properly using the outside heat sinks and two smps in the center.
Means 2x1200W @ 2R or 2400W @ 4R of high quality in a 2 unit enclosure. Short style (300mm), without fan.
But before that I have to settle my car hifi sub....

Listening chain of today:
- 8200 CDQ (CD and pre amp)
- Squeezebox Touch (Flac, MP3, internet radio)
- Two different speakers

With more careful listening sessions the old battle between to different speakers came up again:
- The grey granite type offers slightly more voluminous mids and voices are slightly closer to the listener.
- The brown marble type with the ribbon tweeter from Lake West again is finally winning the game, because of lovely resolution without any aggressiveness.

The amp itself? - I designed and build it short time ago, I am afraid I am biased.
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Old 9th April 2013, 06:28 AM   #386
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Niceeeee...!!!
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Old 9th April 2013, 10:46 AM   #387
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Why are the heat-sinks so abnormally big? they look like heats sinks suited for class-AB amplification ?
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Old 9th April 2013, 11:22 AM   #388
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Nice home cinema speakers. But I think they can not eat anything like "2x1200W @ 2R or 2400W @ 4R ". This kind of power level is more suited for 18" od 21" PA subwoofers / line arrays and the like.
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Old 9th April 2013, 07:21 PM   #389
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@Tom:
...definitely overkill
Like driving a SUV or PickUp.
Fortunately the amp wastes a factor 1000 less energy and resources vs a SUV.

@Reactance:
In class AB the size would be OK 2x150W. Not for 2x1200W.
But true - the amp needs less. The heat sink as shown on page 27 in #261 is fine for my choice of short dead time and continuously driving 2R full power without forced cooling.
If less heat is desired, simply enlarge the dead time.
I like the appearance of the enclosure and oversized heat sinks are not harmful.
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Old 10th April 2013, 02:34 PM   #390
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On the topic of heat dissipation are you able to play music at a reasonable music level without *any* heat sinking ? of course with reasonable dead time its achievable... (I like small heat-sinks makes the unit light weight and innocent similar to the look and feel of hypex modules)
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