Signetics NE5532 was a one of first op-amps designed for the audio. It was a little thin sounding until Signetics factory burned down around year 2000 and they stopped making it. Texas Instruments acquired license, made larger die and produced better (fuller) sounding amp. Chips from TI have small outline of the state of Texas on the top.
I had them in my Benchmark DAC1. I replaced them with LME49860, an audio op-amp that Benchmark ended up using in current products. Sound became a little fuller and more vivid. Still, we're talking about minuscule changes here and even chief engineer of Benchmark John Siau praised NE5532. Here is his exact quote:
I had them in my Benchmark DAC1. I replaced them with LME49860, an audio op-amp that Benchmark ended up using in current products. Sound became a little fuller and more vivid. Still, we're talking about minuscule changes here and even chief engineer of Benchmark John Siau praised NE5532. Here is his exact quote:
Don't underestimate the NE5532. We have just completed a very comprehensive set of tests on the NE5532 and on various substitutes. We have not found anything that will equal the tranparency provided by the NE5532.
Some have suggested susbstituting OPA2134 op amps in place of the 5532s. This is a bad idea! Our tests show an increase in both 2nd and 3rd harmonic distortion, and the addition of higher order (4th, 5th, 6th, and 7th) harmonics that are virtually absent from a stock DAC1. In addition, IMD will increase, and SNR will degrade.
The NE5532 is power hungry, it has high input bias currents, and high offset voltage, but it can drive high-level low impedance circuits with ease. The 5532 should not be used with low signal levels, and it should only be used in low gain circuits. Also, the offset voltage must be managed with appropriate design techniques. I believe the NE5532 has aquired a bad reputation because it has often been missapplied. The DAC1 is carefully designed specifically for the NE5532 op amp. It may surprise you that the NE5532 was selected for transparency and not on the basis of cost.
John Siau
Director of Engineering
Benchmark Media Systems, Inc.