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RE: TDM crossover - opamps upgrade?

Posted by KanedaK (A) on June 10, 2018 at 03:42:20

In Reply to: RE: TDM crossover - opamps upgrade? posted by Tweaker456 on May 28, 2018 at 09:56:49:

I'm sure - for having tried it myself - that the lM4562 n the right circuit sounds better than NE5532.

what's I'm scared of is the likely inadequacy of the local decoupling for the faster LM4562. I remember having to try different decoupling schemes using 0,1uF MLCC capacitors close to each opamp. In my cD player (where NO local decoupling was originally present! no kidding) I settled for one 0,1uF from V+ to V- pin under each chip, and one 0,1uF from V- to ground, almost ON the pin.

Here I have 0,1uF close to each pin (V- and V+) for each input and output buffers (about 0,2 inch close) but the other opamps on the circuit share a couple of 0,1uF wich are located on the power rails between 1inch (closest opamp) and 2inches (fartest opamp) of the chips, wich I think won't be good enough for LM4562. I wonder, if I add local decoupling 0,1uF under each chip, if I should leave the original 0,1uF on the power rails, or if the redundance might prove detrimental and I'd better clip them off?... power rails also have, for each channel, a bunch of 100uF electrolytics (Nichicon KZ): two are located about 2inches aways from the input/output buffers, and two are located about 2inches from the filter opamps. I guess those are well located and will stay there. I don't think I need to add more capacitance with electrolytics closer to each opamp?...

It's all very complicated because I'm completely sure the crossover WILL sound better with better opamps BUT I'm scared of oscillations or bad behaviour and I don't wanna ruin the circuit. I don't know much but i do know opamps aren't "plug and play"...

I'm also planning to use machined, gold-plated sockets; not because I wanna be able to "roll" different opamps in the future, but because I don't own a temperature-controlled soldering iron, and I'd rather overheat the sockets instead of the chips themselves; but i've read sockets can be detrimental for the performance (even tho everybody seems to use them nowadays)...

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