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Looking for a 20A, 500W AC power supply
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T3sl4co1l:
Ah, that makes more sense then.

Agreed, get an audio amp of suitable rating, calibrate its gain, use an isolation transformer (on the output) if necessary (easy enough to use a 12+12V or 24+24V 1kVA toroid and leave the primaries unconnected, just use the two secondaries -- which reduces capacity, hence 1kVA).

Don't forget an inductor (possibly a tapped one, with whatever switching/adjustment you find necessary and suitable) to get the output impedance correct.  On the order of (12V / 12A) / (2 pi (100Hz)) or 1.1 to 11mH.

Tim
j_omega:

--- Quote from: Hexley on July 14, 2022, 09:25:25 pm ---25 volts and 20 amps implies a 1.25 ohm load; and 100 to 1000Hz is comfortably within the audio range. So maybe you can look at a "mono block" audio power amplifier, and surround it with the rest of the bits needed to flesh out your requirements.

For example, you could integrate the following:

* A cheap function generator to generate sine waves of adjustable frequency. That drives:
* An audio power amplifier rated to deliver 20 A into a 1.25 ohm load. Might be able to use a cheapo Class D amplifier intended for car audio.
* A 12V/50 amp switching power supply to run the power amplifier.True, this makes for a multi-box solution. But if you are putting together a specialized test bench, maybe that could be managed?

--- End quote ---


--- Quote from: T3sl4co1l on July 14, 2022, 10:46:44 pm ---Ah, that makes more sense then.

Agreed, get an audio amp of suitable rating, calibrate its gain, use an isolation transformer (on the output) if necessary (easy enough to use a 12+12V or 24+24V 1kVA toroid and leave the primaries unconnected, just use the two secondaries -- which reduces capacity, hence 1kVA).

Don't forget an inductor (possibly a tapped one, with whatever switching/adjustment you find necessary and suitable) to get the output impedance correct.  On the order of (12V / 12A) / (2 pi (100Hz)) or 1.1 to 11mH.

Tim

--- End quote ---

I actually already looked into the audio amplifier idea. I planned out a system using a Rockford Fosgate R2-750x1 amplifier powered by a MeanWell SE-1000-12 supply. Initally, this appeared to be a very affordable solution. However, as I was double-checking all of the specs, I noticed that the frequency response of the amplifier was 20-250 Hz. After looking at several other amps, I realized that this was normal. Some go up to 500Hz but that seems to be the limit. I believe this is because they are intended to drive large bass speakers.

I also haven't spent much time in the audio world so I may be looking at the wrong things. Can you point me in a better direction?

j_omega:

--- Quote from: joeqsmith on July 15, 2022, 01:20:20 am ---I can't help with your question but noticed what appears to be an Odyssey battery on your bench.  What are you doing with this setup?

--- End quote ---

The battery is unrelated to this project.
BrokenYugo:
You need a hifi/PA amp, not an automotive subwoofer amp, should be pretty flat from 20Hz-20kHz. Or build one, they aren't terribly complicated.
j_omega:

--- Quote from: BrokenYugo on July 15, 2022, 05:43:28 am ---You need a hifi/PA amp, not an automotive subwoofer amp, should be pretty flat from 20Hz-20kHz. Or build one, they aren't terribly complicated.

--- End quote ---

Thanks, that helps a bunch. You're thinking of something like this, correct?
https://www.crutchfield.com/p_859XLS1002/Crown-XLS-1002.html?tp=63633
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