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Class D Switching Power Amplifiers and Power D/A conversion

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Old 28th October 2006, 02:38 AM   #151
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Quote:
Originally posted by ChocoHolic
... no idea witch switching frequency she is using.
urghs, wanted to say 'which' of course !
No witches, wizzards or devils around here.
 
Old 28th October 2006, 02:44 AM   #152
Eva is offline Eva  Spain
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I use 50Khz to mazimize efficiency. BTW: I have never took the power ratings of Fred seriously.
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Old 28th October 2006, 03:14 AM   #153
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I am also wondering.
But 240Vpeak is making some power into 8 ohms...
There is no contradiction.

Except that his results are by far better than what I would expect to be achievable with current components.

BTW:
Are you still awake? Right now coming home from party?
Or up again?
 
Old 28th October 2006, 04:14 AM   #154
Eva is offline Eva  Spain
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My sleep is fragile...
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Old 28th October 2006, 01:50 PM   #155
Pafi is offline Pafi  Hungary
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Interesting specs:

"Power Ratings 4ohm: 6000W RMS per channel.

Power Consumption: 2000 VAmax at 4 ohms at 1/3 of power per channel."

So efficiency is 100% at least! :-)
 
Old 28th October 2006, 03:01 PM   #156
Eva is offline Eva  Spain
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Seems like an estimation, or better, a guesstimation...

I wonder whether Fred has the required equipment to measure exact reactive and resistive power consumption of an appliance or not (with THD, PF, etc...)
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Old 28th October 2006, 03:02 PM   #157
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How the
 
Old 28th October 2006, 04:44 PM   #158
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" ... copy of certification obligation for class d product ..."

Building codes: Best to examine generally accepted electrical building practices and codes. Here in the states, any power lines, speaker runs, or other wires with more than 70.7 Volts (AC or DC) have to be inside of pipe (or inside of a cabinet) or well insulated to beyond 600 volts (ala Romex). (Notes: 70 VAC can shock anyone badly enough to stop the heart. 28 VDC can cause a nasty burn and I've got scares to prove it ... )

FCC Rules: It would be a good idea to check out the ARRL Handbooks (Amateur Radio Relay League) for commonly accepted wiring practices that comply with FCC rules about spurious radiation: Example: FCC allows no more than 400 milliWatts (detectable at one meter distance) of radiated power at any and all frequencies (RF, LF, VLF, HF VHF, etc.), to leak outside of any power supply enclosure. (Interestingly, a well sealed enclosure works in both directions, preventing radio noise from leaking out and preventing outside audio and radio interference from leaking in = better rejection of noise = better "noise floor" = cleaner audio ...)

UL & CE Rules: Ignore the UL certification (in practice the certification can be "bought" for average of US$10,000) and go for the gold standard, the European CE complience ratings. Complience is a very good idea in any case, even if you don't bother getting CE certified (it too is expensive) === This reduces potential law suits, negates getting kicked out of town by local fire marshals, can pass muster with insurance companies, etc. As long as you stay "commercial grade" rather than "consumer grade", complience may mean simply making sure no one can stick fingers or screw drivers into the high voltage area. (Example: check out case building practices for outfits like Crown, et al. Note that some companies use "torex" headed screws to fasten the case together = keeps kids fingers outta there ...)

... I am not the authority, but there are authorities here on this Forum. Asking questions about specifics on another thread would be a good idea.

...
 
Old 28th October 2006, 05:19 PM   #159
Variac is offline Variac  United States
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Fredos has made no effort to obtain an AVB thread to transfer this thread after saying that he would. The premise of this thread is to discuss his business.

Members are constantly complaining about the commercialization of the "regular" part of the forae, so we are forced to close this thread until fredos does as he said he would and gets the AVB thread.

When he does we can copy this entire thread to it and he can then discuss his amps as much as he wants. Even compare them to other amps. New posts notification will still appear on the home page and this thread can continue as he wishes.

We are trying to move all commercial interests to AVB and appreciate cooperation. This is not a punishment, we are just obligated to maintain a distinction between commercial and purely DIY topic posts.




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