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| Is there such thing as a META42 with a "built-in" high quality power supply, into which I just plug a power cord? |
The META42 board requires DC power, so the simplest thing is to use a good-quality wall wart to convert AC wall power to DC and run that to the META42 board. Because that's the simplest thing, that's how most wall-powered META42s are set up. It's not the only option, though.
Probably the next-simplest alternative would be to get an "open frame" power supply and put that inside the case with the amp board. An open frame power supply is functionally identical to a wall wart, just without all the packaging. I've done this before to good effect. Because linear open frame power supplies are large and I favor smallish enclosures, my first amp like this used a high-grade switching power supply. Switchers are smaller and more efficient than linear power supplies, but they put some noise on the power output. However, a high-grade switcher will have virtually no ripple and it will use very high switching rate so that the noise is all in the high ultrasonic range. I was quite happy with that amp's performance.
Later, someone prevailed on me to build an amp in a rather large case (6" x 6" x 3"), so that I could accommodate an internal open frame linear power supply. So, you can still have linear-regulated power if you really want it. It just requires more space.
A more complex option would be to build your own linear power supply and put it into the amp case. Probably the best reason to do this is that you can design the power supply to meet your needs exactly. For instance, all commercial open-frame linear power supplies I've seen use standard transformers, which are large. Forum member Antness has made circuit boards for Kevin Gilmore's linear power supply which uses low-profile toroidal power supplies. This will power a META42 just as well as it will power a Gilmore dynamic amp, and it will fit into cases that are too small to accommodate any commercial open-frame linear power supply I've seen.
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I would be VERY interested in the sort of thing Happyman is looking for...
Something like this: A homemade (read: CHEAPER!!) version of the Cosmic/Base Station One concept... |
This really isn't the same thing as I described for Happyman. There are two main configurations I've done, which are not identical to the Cosmic's power scheme, but which are close.
One kind puts the amp in its own enclosure, and you can plug either a battery pack or a wall-power supply into the amp. Just as above, you have a choice between wall warts, open frame power supplies in separate enclosures, or DIY'd power supplies in separate enclosures. This is the closest I've come to a Cosmic-like setup. The really neat trick in the Cosmic amp is that it has a DC-DC converter inside so that the external power supplies can be 5V, despite the fact that the amp's internal circuitry must need at least 12V. So far, I've gone with simpler configurations like using 1 or 2 9V batteries or lots of AA's rather than using DC-DC converters.
The other way I've done this kind of amp is to put the batteries inside the case with the amp board, and then add a DC power jack that will cut the batteries out of the circuit when you plug a wall power source in. This isn't Cosmic-like at all; it's more like the way most portable CD players work. This is probably my favorite way of doing both battery and wall power.
