Best volume selections on the three channels of an AY-3-8912 chip to emulate an 8-bit DAC. From the list you can see that the AY can't emulate an 8-bit DAC very well (many different D/A values share the same output volumes, particularly toward the end of this table). The sample values 2 through 135 inclusive appears to be a "linear" region where % error in the output is < 0.5%. Restricting samples to these 134 levels allows the AY to emulate a 7-bit DAC very well. DAC bit depths > 4 are achievable on the AY despite the AY only having 3 four-bit DACs because the output drivers are logarithmic. Full details can be found in GI's data sheet. - Alvin D/A A B C ERROR(%) -------------------------- 0 0 0 0 +INF 1 0 0 0 +40.5502 2 1 1 1 -0.6010 3 4 1 0 +0.2098 4 5 1 1 -0.5610 5 5 4 0 -0.0825 6 6 3 2 +0.2401 7 6 4 3 -0.6821 8 6 6 0 -0.3587 9 6 5 5 +0.6209 10 7 6 2 -0.0523 11 7 6 4 -0.6125 12 9 2 0 +0.1763 13 9 4 0 -0.3153 14 9 5 1 -0.4980 15 8 6 6 +0.0525 16 10 0 0 -0.3020 17 10 3 1 +0.0180 18 8 7 7 +0.6513 19 10 5 3 -0.0388 20 9 8 4 -0.0221 21 10 7 1 -0.0790 22 9 9 1 -0.4845 23 10 8 0 -0.0511 24 11 4 2 +0.2066 25 11 4 4 -0.0503 26 11 6 2 -0.2852 27 11 7 0 +0.0435 28 11 7 3 -0.4680 29 11 7 5 +0.6741 30 10 8 8 +0.0827 31 12 0 0 -0.0793 32 12 3 1 +0.0838 33 10 9 8 +0.4095 34 12 5 3 +0.0482 35 12 6 3 +0.3301 36 12 7 1 +0.0199 37 11 10 1 -0.2311 38 12 7 5 -0.0086 39 12 7 6 +0.2459 40 11 10 6 +0.0081 41 12 9 0 +0.2983 42 12 9 3 -0.0488 43 11 11 0 -0.1330 44 13 2 1 +0.1980 45 13 4 1 +0.0555 46 12 10 2 -0.0209 47 13 5 4 +0.0309 48 13 6 4 +0.2369 49 13 6 5 -0.2229 50 13 6 6 -0.0201 51 13 8 2 -0.1382 52 12 11 1 -0.1188 53 11 11 9 +0.1693 54 13 9 2 +0.0737 55 13 9 4 -0.0406 56 13 9 5 -0.4379 57 13 9 6 -0.2563 58 13 10 0 -0.0511 59 13 10 3 -0.2923 60 12 10 10 +0.1130 61 12 12 2 +0.0232 62 14 2 2 -0.0491 63 14 4 2 -0.1470 64 14 5 3 +0.1140 65 13 10 8 +0.0106 66 14 7 1 +0.0966 67 14 7 3 -0.4078 68 14 7 5 +0.0784 69 13 11 7 +0.0441 70 14 8 5 +0.3604 71 14 9 0 +0.2519 72 14 9 3 +0.0501 73 13 12 0 -0.0081 74 13 12 3 -0.2009 75 12 12 10 +0.1220 76 14 9 7 +0.0217 77 14 10 4 -0.0197 78 13 12 7 -0.2158 79 14 10 6 -0.1759 80 13 12 8 +0.0383 81 12 12 11 +0.3877 82 14 11 1 -0.0063 83 13 12 9 +0.1698 84 14 11 5 -0.0186 85 13 11 11 -0.0453 86 15 0 0 -0.0733 87 15 3 1 -0.0134 88 15 5 0 +0.1372 89 15 5 3 -0.0248 90 15 6 3 +0.0857 91 15 7 1 -0.0344 92 14 12 4 +0.0093 93 15 8 0 -0.0284 94 15 7 6 +0.0611 95 15 8 5 +0.1656 96 15 9 0 +0.0874 97 15 9 3 -0.0607 98 15 8 7 -0.1927 99 15 9 6 +0.3705 100 15 8 8 +0.0101 101 15 10 2 -0.0476 102 15 10 4 -0.1080 103 14 13 0 +0.0492 104 14 13 3 -0.0886 105 14 12 10 +0.1410 106 13 13 11 +0.1995 107 15 11 1 -0.0936 108 14 13 7 -0.1035 109 15 11 5 -0.1015 110 15 11 6 -0.0104 111 15 10 9 -0.3333 112 15 11 7 -0.4078 113 14 13 9 +0.1748 114 15 11 8 -0.2261 115 13 13 12 +0.0111 116 15 12 2 -0.0210 117 15 12 4 -0.0739 118 15 12 5 -0.2622 119 15 12 6 -0.1766 120 14 12 12 +0.1432 121 14 14 2 +0.1052 122 14 14 4 +0.0534 123 14 14 5 -0.1283 124 14 14 6 -0.0473 125 14 14 7 +0.3969 126 15 12 9 -0.2748 127 13 13 13 +0.3634 128 15 13 0 -0.0346 129 15 13 3 -0.1451 130 15 12 10 +0.0408 131 14 14 9 -0.1486 132 14 13 12 +0.4701 133 15 13 7 -0.1555 134 15 13 8 +0.7405 135 15 13 8 -0.0058 136 15 12 11 +0.2026 137 15 12 11 -0.5288 138 15 13 9 +0.0743 139 15 13 9 -0.6457 140 14 14 11 +1.0194 141 14 14 11 +0.3029 142 15 13 10 +0.3534 143 15 13 10 -0.3484 144 14 13 13 +0.7426 145 14 13 13 +0.0478 146 15 14 2 +0.0221 147 15 14 4 -0.0203 148 15 14 5 -0.1708 149 15 14 6 -0.1031 150 14 14 12 +0.1523 151 15 14 7 -0.3966 152 15 14 8 +0.3948 153 15 14 8 -0.2614 154 15 14 8 -0.9091 155 15 14 9 +0.4583 156 15 14 9 -0.1857 157 15 13 12 +0.3348 158 15 13 12 -0.3003 159 15 14 10 +0.6979 160 15 14 10 +0.0685 161 15 14 10 -0.5530 162 14 14 13 +0.4180 163 14 14 13 -0.1981 164 14 14 13 -0.8066 165 15 14 11 +0.8074 166 15 14 11 +0.2001 167 15 14 11 -0.3999 168 15 14 11 -0.9928 169 15 13 13 +0.5765 170 15 13 13 -0.0151 171 15 15 2 -0.0367 172 15 15 4 -0.0726 173 15 15 5 -0.2010 174 15 15 6 -0.1429 175 15 14 12 +0.0762 176 15 15 7 -0.3943 177 15 15 8 +0.2853 178 15 15 8 -0.2781 179 14 14 14 +0.7179 180 14 14 14 +0.1583 181 15 15 9 -0.2125 182 15 15 9 -0.7608 183 15 15 10 +1.1009 184 15 15 10 +0.5514 185 15 15 10 +0.0079 186 15 15 10 -0.5298 187 15 14 13 +0.3113 188 15 14 13 -0.2223 189 15 14 13 -0.7502 190 15 15 11 +0.6511 191 15 15 11 +0.1242 192 15 15 11 -0.3973 193 15 15 11 -0.9134 194 15 15 11 -1.4241 195 15 15 11 -1.9297 196 15 15 12 +2.0604 197 15 15 12 +1.5423 198 15 15 12 +1.0295 199 15 15 12 +0.5218 200 15 15 12 +0.0192 201 15 15 12 -0.4784 202 15 15 12 -0.9711 203 15 14 14 +1.0788 204 15 14 14 +0.5833 205 15 14 14 +0.0927 206 15 14 14 -0.3932 207 15 14 14 -0.8744 208 15 14 14 -1.3510 209 15 15 13 +1.6685 210 15 15 13 +1.1844 211 15 15 13 +0.7048 212 15 15 13 +0.2298 213 15 15 13 -0.2408 214 15 15 13 -0.7069 215 15 15 13 -1.1688 216 15 15 13 -1.6263 217 15 15 13 -2.0797 218 15 15 13 -2.5288 219 15 15 13 -2.9739 220 15 15 13 -3.4149 221 15 15 13 -3.8520 222 15 15 14 +3.6464 223 15 15 14 +3.1816 224 15 15 14 +2.7210 225 15 15 14 +2.2644 226 15 15 14 +1.8119 227 15 15 14 +1.3634 228 15 15 14 +0.9188 229 15 15 14 +0.4782 230 15 15 14 +0.0413 231 15 15 14 -0.3918 232 15 15 14 -0.8211 233 15 15 14 -1.2468 234 15 15 14 -1.6688 235 15 15 14 -2.0872 236 15 15 14 -2.5021 237 15 15 14 -2.9135 238 15 15 14 -3.3214 239 15 15 14 -3.7260 240 15 15 14 -4.1271 241 15 15 14 -4.5249 242 15 15 14 -4.9194 243 15 15 15 +4.9383 244 15 15 15 +4.5082 245 15 15 15 +4.0816 246 15 15 15 +3.6585 247 15 15 15 +3.2389 248 15 15 15 +2.8226 249 15 15 15 +2.4096 250 15 15 15 +2.0000 251 15 15 15 +1.5936 252 15 15 15 +1.1905 253 15 15 15 +0.7905 254 15 15 15 +0.3937 255 15 15 15 +MORE