Something like this will work, with a couple of comments.
I would get rid of the second buffer - it is not needed but contaminates the signal path.
Use of relays vs. analog switches: relays give you wider range at high attenuation, at the cost of acoustic noise when you change volume - it can get very intrusive. Analog switches are quiet, but limit your range to something like -65dB. With relays and 16 resistors you can get more.
Minimum attentuation of your volume control will be close to -4dB if you want to keep the attentuation scale linear in dB's.
It is good idea to spend time analyzing the circuit - you can use Exell to do that easily. To simplify the analysis use the conductivity units, NOT resistance.
A volume control like this one, if implemented right, will give you wonderful results. Good luck.
I would get rid of the second buffer - it is not needed but contaminates the signal path.
Use of relays vs. analog switches: relays give you wider range at high attenuation, at the cost of acoustic noise when you change volume - it can get very intrusive. Analog switches are quiet, but limit your range to something like -65dB. With relays and 16 resistors you can get more.
Minimum attentuation of your volume control will be close to -4dB if you want to keep the attentuation scale linear in dB's.
It is good idea to spend time analyzing the circuit - you can use Exell to do that easily. To simplify the analysis use the conductivity units, NOT resistance.
A volume control like this one, if implemented right, will give you wonderful results. Good luck.
I think it counts a binary register up and down and writes it to the relais. The MC would write with a special algorithm to avoid switch noise. I think when switching it cares for don´t do to large steps at a moment, or only switch one relais at one time. Could anybody decribe how this is implemented in a MC? I managed now to build a programmer for flashpics, and a PIC16F876 reading a rotary encoder with pushbutton funktion, counting up and down, write binary out on a port for relais, and write number to a LCD. What i need next is this special algorithm against the noise.
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