Hey I am toying with a design for just a simple box that mixes two line level signals.
User control is just a rotary 'balance' pot that essentially crossfades between the two input channels (full CW is 100% channel 1 0% channel 2, center is 50% of each channel, likewise for CCW)
It seems the simplest way to do this would be to use a balance pot to complimentarily attenuate the input channels, mix the signals passively, and then provide a high input impendance, low noise opamp to provide a set amount of make up gain.
The schematic is posted here:
http://us.f2.yahoofs.com/bc/40d9c668_dc36/bc/groupdiy/LC.pdf?BCYNWLCBp6.b8TY6
The balance pot is a 50k Alps Black Beauty.
Inputs are transformer coupled and so is the output.
The opamp was just for simulation, I'll be using a FET input one of my own design.
The load on each source would be around 20k at the least.
The sources will most likely be high quality balanced studio equipment (preamps, compressors and such)
Any comments on how the crossfading/mixing is done? Do you guys think an active mixer would be better for this? I figure since it's only two channels the noise contribution won't be too bad.
I'm using Percy Audio for the balance pot. Anyone know an alternate source for these?
Also I figure a 50k quality carbon comp pot (Alps Black Beauty) would be better in this case than a 100k conductive plastic (TKD) one for double the cost. Comments on this?
User control is just a rotary 'balance' pot that essentially crossfades between the two input channels (full CW is 100% channel 1 0% channel 2, center is 50% of each channel, likewise for CCW)
It seems the simplest way to do this would be to use a balance pot to complimentarily attenuate the input channels, mix the signals passively, and then provide a high input impendance, low noise opamp to provide a set amount of make up gain.
The schematic is posted here:
http://us.f2.yahoofs.com/bc/40d9c668_dc36/bc/groupdiy/LC.pdf?BCYNWLCBp6.b8TY6
The balance pot is a 50k Alps Black Beauty.
Inputs are transformer coupled and so is the output.
The opamp was just for simulation, I'll be using a FET input one of my own design.
The load on each source would be around 20k at the least.
The sources will most likely be high quality balanced studio equipment (preamps, compressors and such)
Any comments on how the crossfading/mixing is done? Do you guys think an active mixer would be better for this? I figure since it's only two channels the noise contribution won't be too bad.
I'm using Percy Audio for the balance pot. Anyone know an alternate source for these?
Also I figure a 50k quality carbon comp pot (Alps Black Beauty) would be better in this case than a 100k conductive plastic (TKD) one for double the cost. Comments on this?
