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JRC 4565D op-amps & Nichion caps

post #1 of 16
6/7/07 at 6:30pm
Thread Starter 
I been thinking of mod'ing my Toshiba SD6109C Receiver with better op-amps & maybe caps. I cracked her open to see what's inside. From what I can see, all the through-hole radial caps are Nichicon, and the SMD ones I am not sure. The two BIG power caps are 8200uF 50wv Nichion CE 85ºc LQ (M), and the rest of the smaller caps are Nichion VX (M).

As for op-amps, I can see four JRC 4565D 9099B, and possible two more that I can't see (I haven't fully taken it apart). I am not really sure what DAC it has on it, Google just says it's has a 24bit 96khz for the DVD and a 10bit DAC. There is a chip I see, but I think it's the 5.1 surround sound chip: CRYSTAL CS492604-CL ATAFTD9925 with a DD & DTS logo on it.

Should I replace all JRC op-amps with LM4562's? and what about the caps?
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post #2 of 16
6/8/07 at 4:09am
Thread Starter 
?
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post #3 of 16
6/8/07 at 6:17am
I wouldn't replace all caps. Look if there's a cap directly in the signal path (the output coupling cap), and replace it with either a wire bridge or with a high quality polypropylene cap in the size range of 0.47-1.5uF. Wire bridge only if you measured your DC offset and if it's low enough. Never heard about the JRC4565, socketing them and replacing them with other opamps might indeed be a good option.
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post #4 of 16
6/8/07 at 6:29am
Thread Starter 
If you can find the signal path & output coupling caps here, let me know

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post #5 of 16
6/8/07 at 7:57am
You would have to look close at the RCA output jacks. there it should be, prominently sitting next to the output. Can't see very much on that pic, the caps on the opamp 'strips' seem to be power reservoir caps (at least nice to see every opamp get its own power supply), and the ones on the right seem to be also some kind of power supply caps.
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post #6 of 16
6/8/07 at 3:14pm
Quote:
Originally Posted by balou View Post
(at least nice to see every opamp get its own power supply),
but those 10uF are soooooo far away from the opamps leads, kind of defeating the purpose
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post #7 of 16
6/9/07 at 7:14pm
Thread Starter 
For me replacing the teeny-tiny SMD caps is out of my experience. What about replacing the JRC op-amps? Are they 8-SOIC's? They're about 1/4" square, mebby alil less. I am thinking of replacing them with LM4562's.
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post #8 of 16
6/10/07 at 7:41pm
Thread Starter 
Quote:
Originally Posted by Joshatdot View Post
What about replacing the JRC op-amps? Are they 8-SOIC's? They're about 1/4" square, mebby alil less.
?
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post #9 of 16
6/11/07 at 6:02am
Thread Starter 
what is it..do I smell?
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post #10 of 16
6/11/07 at 7:00am
They look a bit strange for so-8 chips... maybe they are pssop or some other strange package. Maybe http://en.wikipedia.org/wiki/Small-O...grated_Circuit will help you to determine what they really are

edit: are they 5x5 mm? then it's a dmp8 package... never heard of it before either..
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post #11 of 16
6/11/07 at 7:26am
Thread Starter 
I found a similar op-amp, the JRC 4559 and it comes in SSOP8.
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post #12 of 16
6/11/07 at 7:35am
I checked it, soic-8 chips should work. they are a bit less wide than dmp-8, but it should work anyway (total length and lead pitch are the same)
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post #13 of 16
6/11/07 at 12:16pm
yeah, DMP-8 is just a little wider than SO-8, most SO-8 parts will fit.

By the way, if any of these opamps is used in an open-loop configuration, using a chip with a different open-loop gain will alter the performance of the circuit.
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post #14 of 16
6/12/07 at 7:42am
just had a look at my noisy soundcard which I ripped out of my computer because it was.... noisy. this thing also has a jrc 4565. seems like I have to order a few ad8066 for replacement

yeah.. tweaking of bottom end stuff

edit: I think with budget stuff, you can get the greatest quality improvement with the smallest investment. couldn't get any more horrible anyway
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post #15 of 16
6/13/07 at 4:13pm
The opamps aren't the reason for the noise. they might make it sound coarse and unrefined, but not noisy.

More likely power supply issues. PC power rails are very noisy, takes effort to clean it up.
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