Need help on R2R ladder resistor values

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Hi,

I am interested in building an r2r relay attenuator ( 256 steps logarithmic ) and I'm using this calculator to determine the values: The δ1 relay-based R-2R stereo attenuator.
The problem is that I got mixed up on which parameters should I look for in order to make the correct calculations. The attenuator will be used between the source ( musical fidelity x24k dac ) and a diy buffer preamplifier circuit ( pinkfish's B4 bootstrap preamplifier ) and will drive my Bryston 4BST power amplifier.
So, what sould I look for in order to buy the appropriate resistors?
 
I've found a review that they've measured my dac's output voltage is 2.2Volts with an output resistance of 48 Ohms. The first resistor on the preamp's input is 10K. I know that I could change the preamp's input resistor to about 20~25K by also replacing the input decoupling capacitor to keep the lower frequency cornering but if I keep preamp's input resistor at 10K, that means that Zatt would be equal to Zload. First of all, is this acceptable and if so, I should leave the RT resistor spot blank?
 
Sorry to be a jerk, but an R-2R ladder uses some value R, and the value 2*R. Only those two values - that's why it's called R-2R. It's a linear attenuator though, with a constant linear attenuation per step, and not the logarithmic one that's popular now.

A logarithmic ladder having N steps uses 2*N different values - a totally different ladder.

Again, sorry to be a jerk, but I wish we could come up with some name other than "R-2R" for these logarithmic ladder attenuators. Maybe 'logarithmic ladder'?

Carry on...
 
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