I was just curious because my lf353 chips both shorted and sent my Parasound 2125 power amp into protect mode. I have some lm353 chips but, I put OPA 2132pa chips in instead to try and the amp sounds much better with more detailed midrange and high frequencies. These chips are mounted on the small board with the RCA input jacks on it. Thanks! 🙂
Lm353, lf353, same stuff, different manufacturers.
The opa2132 is a more modern device. Better specs but it oscillates more easily in a sub-optimal layout. The pessimist in me would check if the increase in details is not the result of oscillations.
The opa2132 is a more modern device. Better specs but it oscillates more easily in a sub-optimal layout. The pessimist in me would check if the increase in details is not the result of oscillations.
I'm not sure how to check them they don't run hot or anything I also replaced the decoupling caps with larger ones also, hoping that might help to keep them stable. I'll keep a check on the sound especially, at higher volumes. Thanks! 🙂
Here is a schematic showing the op amps and decoupling if that helps they are in the upper left corner. 🙂
Well, I'm glad I broke out my lighted magnifier because the extra chips I thought were lm353p, turned out being lm359p comparator chips 😱
Hi Andrew, I have some orange drop polypropylene 0.1mf caps which, are really rather large in size I could put at each +/- power pin of the chips to ground would that be sufficient to make sure the chips remain stable? I think, I may still have some smaller .01mf orange drop caps also. I plan to place an order for some components soon so, what type of small caps would you recommend I order for bypassing the power pins of op amps in general? I've tried the opa 2134, and 2604 but so far, these opa 2132pa chips sound the cleanest it's even easier to understand what people are saying when watching movies on my 2 channel setup. The four decoupling caps are about 1/2" from the chips being 50mf. 35v. I really like the sound of the 2132 chips I just want to make sure they are properly bypassed. Thanks very much! 🙂
HF decoupling can use X7R ceramic.
The losses inside the ceramic act as an effective snubber and help prevent instability.
Whereas a very low ESR capacitor can promote instability.
You are not bypassing the power pins.
The decoupling capacitors are supplying the current, into the chip/device, demanded by the load that is prevented from coming quickly out of the distant smoothing capacitors due to excessive rail impedance.
The losses inside the ceramic act as an effective snubber and help prevent instability.
Whereas a very low ESR capacitor can promote instability.
You are not bypassing the power pins.
The decoupling capacitors are supplying the current, into the chip/device, demanded by the load that is prevented from coming quickly out of the distant smoothing capacitors due to excessive rail impedance.
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