You're off again, as usual:...Go with lm4562 instead and you won't regret it with your Soundcraft...None of the circuits you have there using bipolar op-amps is in trouble with the input current noise.
I don't think there's a whole lot to gain - aren't these the output drivers with their 22k and 100k resistors anyway? LM4562s are only going to be more noisy under these conditions (as you should find out if you plug in their voltage and current noise densities with these part values - I'm getting about 4 dB more output noise), and NE5532s are fine line drivers as-is.
At this point, I totally agree; that's what I'll do with my Soundcraft mixer. I'm actually looking for ON Semi NE5532s in DIP form to put in my tape machines, as they are just enough of an upgrade over the NJM4559s to be worthwhile. I did mange to find some old NOS Philips NE5534s, which should arrive soon; but they didn't have any 5532s.Where there already are 5532s now I'd just leave them as-is. Maybe add some local rail bypassing. I think upgrading the TL072s with e.g. OPA1642 as planned should do for now.
You're off again, as usual:
Originally Posted by dotneck335
Now the only thing remaining is the bus drivers---which are currently NE5532s, which really are fine ICs for the most part. I could also replace those with LM4562s, which are quieter, cleaner, and faster.
That's excellent advice; thanks. I have had trouble in the past with 4562s, and never thought of doing that.But watch out for the RFI immunity issues - sometimes as a voltage follower the LM4562 can pick up radio stations if the inverting input is directly connected to the output (internal oscillations?) 100 ohm resistor in the feedback path apparently cures this. (As reported by Doug Self in his Active Crossover book)
I'm actually using the 1k max value prescribed for common mode canceling technique resistors in his "Small signal" book.For some njm's you can safely use higher values up to 100kohm depending on application.100 ohm resistor in the feedback path apparently cures this. (As reported by Doug Self in his Active Crossover book)
Yeah, I think that's the best approach. I got a quote from Heisener for DIP form NE5532As; then I asked if the ICs were genuine ON Semi devices, and then all of a sudden the price tripled. I don't think I'll do business with them.On Semi SOIC8 ones on a SOIC->DIP breakout is a possible way to go.