| Keep in mind that the opamp's open loop gain is directly related to the amout of THD you will have and the ability to sum a large number of inputs without running out of loop gain.
Although the sum amp's signal is run at unity gain, the amplifier is running at a much higher loop gain. 8 channels wouldn't be a problem, just try it in a trident with 40 inputs to hear what I'm discussing here.
My choices for sum amps:
LT1357
THS4011
OPA134
OPA627
LT1128
Avoid the AD797 as it has a complex phase curve and tends to be unstable, besides, it sounds like crap.
The op176/275 sounds boring, try the OPA134 instead.
If you need mondo output current, a pair of complimentry transistors in the loop will allow tons of current in case you need to drive the signal into a 50 ohm load.
Jim Williams
Audio Upgrades
Remember! They don't work if you let the smoke out.
Jim Williams
Audio Upgrades |