Joined: Fri Aug 30, 2002 1:09 am
Posts: 8543
Location: Southern California
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When I worked at TEAC in 1982-83, they considered line level in the semi-pro high-impedance unbalanced stuff to be -10dbV, or 316mV RMS, which is .894Vp-p for a sine wave. If you can swing 5Vp-p, that's +15dB. (Professional studio line level is much higher, at +4dbm into 600Ω balanced, which is 1.23V for 0VU.) Voltages for 8Ω earbuds will be lower. I have not measured any of the modern ones, so you might want to do that and experiment.
I have example circuits (which I'm actually using on my workbench computer) for A/D and D/A converters on the circuit potpourri page of my 6502 primer at http://wilsonminesco.com/6502primer/potpourri.html#ADC and http://wilsonminesco.com/6502primer/potpourri.html#DAC . They're only 8-bit; but 8-bit is capable of sounding better than the cassettes at the end of their reign just before CDs took over which is pretty darned good, and these converters are fast. You don't have to tell the A/D converter to start a conversion and then come back later when it's finally done. It's almost fast enough to just read it as a memory location, and select it, and find the data available by the end of the same cycle. The D/A is even faster, settling to ½lsb is 150ns (right—not µs, but ns).
_________________ http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?
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