[ARC5] Fwd: Smart People: 60Hz Transformers Faster?

[Scott Robinson]

Hi David,

You can buy pretty large class D (switching) audio power amps these days 
for not a lot of money. You'll probably need a 250W 32V transformer, 
since 1 KW into 8 ohms is about 90V. You wire the 32V transformer with 
the primary across the PA output and the secondary in series with the 
load, phased to increase the voltage.

Most likely what you'll find is a stereo amp, so you get a 500w/ch amp 
and run it in bridge mode (the two channels out of phase) and get 180V 
rms, which you will again need a transformer to sort out. It is probably 
  net cheaper to buy a larger amp, which can generate a larger output 
current, and run it at less than full power.

Be aware that audio power amp ratings are generally short term; the long 
term power available may be much less. Look at offerings from QCs and 
Crown to start with. If the amp is rated to drive 4 ohms, twice the 
current is available.

Note that these amps, although they will presumably pass the radited 
nose standards, will radiate at least some RF.

More questions, ask!

Peace

Scott

On 11/23/15 7:59 AM, David Stinson wrote:
>
> ----- Original Message ----- From: "Scott Robinson" <spr at earthlink.net>
> Subject: Re: [ARC5] Fwd: Smart People: 60Hz Transformers Faster?
>
>
>> 3) As a designer of, among other things,  switchmode power supplies, I
>> will say that none of them that I have seen use half-wave
>> rectification. Diodes are cheaper than monster electrolytics.
>
> Thanks for the insight, Scott.
> If you needed to deliver 115 VAC at 1000W, 800 Hz,
> how would you do it?
>
> 73 Dave AB5S
>
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