If you use a binary counter and a comparator you can accomplish a A to D with R2R.
Quote from: TomGeorge on Jun 25, 2014, 01:21 pmIf you use a binary counter and a comparator you can accomplish a A to D with R2R.Actually, it's not a Binary counter, it's a SAR, a Successive Approximation Register. The general concept is a DAC - such as a resistor ladder - which generates trial values which are then compared to the input value, making a decision at each step as to whether the approximation is greater or less than the input.The SAR does not simply count through single increments however, but starts with an approximation of half the reference value. According to the comparison it next tries either a quarter or three quarters, and continues to halve the test interval at each step. By doing this, it determines one binary bit of the value for every trial and so requires only as many trials - approximations - as bits are needed.
With a bag of 1% or 2% resistors and a meter, I'm pretty sure that some will be closer to dead nuts than others so those would be the ones for the high order bits.
I used these in the old days.http://www.physics.ucdavis.edu/Classes/Physics116/MC1408-dac.pdf
Were you making audio and if so, how was it?