Quote:
| What's an appropriate voltage |
Answered in full detail here:
http://tangentsoft.net/audio/opamp-wv.html
I even use the AD843 in one of the examples.
Quote:
| how much current does one need? |
It's easy enough to add up the quiescent current of the major parts in your amp. In a PIMETA, you can probably get within 10% by adding the IC quiescents (don't forget to account for changes when using R11 on the buffers, or when stacking!). The final 10% is in any class A biasing, LED current, etc.
Once you know the Iq of your amp, multiply that by 1.2 to get the bare minimum supply current. (You'd multiply by a higher value if supply current went up much in operation, but it won't, with a PIMETA, unless you're using really inefficient phones.) I think you'll find that you can't buy a supply with current that low, so in fact the point is moot, for a PIMETA.
Quote:
| Is 22 awg wire enough for the like, 12watts at most a PIMETA might use? |
First, you're off by about an order of magnitude on the wattage.
And as for wire rating, I seem to recall that 22 gauge is good for up to about 1A. Do a Google search...there are lots of tables for current vs. wire gauge out there. You don't want to get anywhere near the limits, though, because the limits are effectively telling you where the resistance of the wire is causing significant voltage drops. In a headphone amp, that means ripple, which means you're losing power supply performance. I point this out because some have tried using 30 gauge wire and such with heapdhone amps. Yeah, it may technically work, but it isn't a good idea.
Quote:
| Eh, not sure I want to mess around with yet another circuit. |
The circuit BrokenEnglish mentioned really isn't that hard to construct, but even so it's overkill. All you absolutely have to have is a bare 78xx series regulator and an unregulated wall wart. You could even save yourself the protoboard cost by air-wiring the regulator to the inside of the DC input jack. Total cost, probably $6.
You aren't going to get "cheap AND good" without some effort, Emon.
Quote:
| By the time you tack on a transformer, IEC, and a few other parts the cost [of a Velleman K1823] is about the same as the Elpac. |
Yes, but
the performance level is higher.
Quote:
| So the velleman kit K1823 would be wired inline between the DC input jack and the power input on the Amp board? |
You could use it that way by bypassing the bridge. (Even that isn't strictly necessary, but the bridge isn't doing you any good in this situation.) But if simple is your thing, I still recommend the unregulated wall wart plus 78xx route.
