Quote:
Originally Posted by Jim Williams  072's are problematic for me in EQ's. There is too much noise to use them for HF boost. They have only 40 db open loop gain at 10k hz, add + 15 db of HF boost and that opamp has 25 db of loop gain left to push down distortion. That creates high THD.
Better choices (if housecleaning work like phase compensation and power supply decoupling is done) are the National LME49720NA or the Analog Devices AD8599, the LT1358, the OP-275, the BB OPA2134, AD8512, etc.
Some of those have 80 db open loop gain at 10k hz, 40 db less dirt. Compare the AD8599 .9 nv/hz/sq noise to the 072's 22 nv noise.
Jim Williams
Audio Upgrades |
Certainly there are better new parts. If the topology is calling for a lot of closed gain at any frequency use a quieter part. The phase shift and higher distortion due to modest loop gain margin are probably worse on paper than in real life. I personally drew a line at about 15-20 dB of gain, but then was then and now is now. YMMV
JR