# OPAMP upgrade for crossover, 12 volt, JRC 4680D to something much better needed



## RAAM (8 mo ago)

I have searched all over the net, including here and found some good recommendations but wanted to see if anyone here can help as I have had no luck getting the schematics. I know it runs on +12V (measured 11.4VDC, home audio gear in use in our full time RV) Several options available but no direct replacement recommendations considering the supply voltage and some opamps have oscillation issues, need bypassed, etc but just not enough info to make a good decision. 
I have spent hours over several sessions going over the circuit board to plot out the schematics but end up getting a headache and giving up...
There are only 4 opamps in the circuit, set high pass to main speakers, adjustable to the sub, not likely need all 4 but just going to do them. Also will upgrade caps on the board, PS and signal path, any others as needed. 
I am OK with 80hz highpass, the speakers drop off quickly after 70hz anyway so no real need to swap resistors, all good metal film on the board. 
Best opamps I can get that are an easy fit(they are soldered to the board, not DIPS but no worries there) I can get that are not crazy expensive, best quality for a reasonable price is what I am looking for, LM4562, NE5532, OPA.......$5-10 a pop would be nice, double that if I must. 
Feeding into a tub amp but not SET so not quite as laid back and smooth and has extended highs, super tweeters on the Edgarhorn Slimlines. I like smooth and have always enjoyed BB DACS but now using a AKM which is not bad. 

Thanks
Rick


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## bnae38 (Oct 3, 2015)

The 4580 (assume you mistyped) is a decent opamp. Why do you want to change them?


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## bnae38 (Oct 3, 2015)

If you insist.. opa2209 is a great non-fussy bipolar input opamp that performs well in most circuits in place of ne5532 or 4580.. though they are both very good anyway .


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## RAAM (8 mo ago)

Thanks and correct, a mistype. I have read everything I can find on the JRC4580 and found comments that it is a lower quality part than other options including from different manf with same part number, not JRC. I do not recall seeing the OPA2209 recommended anywhere but sure going to look into it. 

I just want to make sure no loss of signal quality going into the tube amp, I know, lots of distortion there but....I also love to mod things. I actually forgot to test this out as my BD player had a sub out so never used the high pass in the many years using the SA1000. If I cannot hear a difference when I go through the crossover, except a slight loss of low end, I will leave the opamps in place. 

The caps might still be something I should do, the PS ones I have not been able to see the brand yet, the ones by the opamps are J.Y. brand, many great low cost quality caps available for cheap and easy to replace them. 

Thanks again!
Rick


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## khlae (Dec 31, 2016)

I had a completely different device that used jrc4580 opamps, I replaced them with lme49720 opamps. 

Those JRC opamps seem to have very good noise rejection numbers, and switching away from them led to a significant increase in noise floor, all the other opamps I had researched all those years ago (including the lme49720) have worse common mode rejection ratio and other such signal to noise ratio characteristics as compared to the JRC4580. Or something like that. Something to be aware of.


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## RAAM (8 mo ago)

Thanks, I will put the SA1000 back together and hook up the tube amp and some KEF line arrays I have here to see if I can tell a difference. The Edgarhorns are still burried in storage where they have been since 2115, all the way in the back of a 15x30 unit stacked 12 ft high in the area they are in.


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