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Luxman L230 left channel white noise

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pcrosewood

Active Member
Hi All,
I recently recapped my Luxman L230 amp. Now I'm getting white noise from the left channel when set to phono. All the other setting like tuner, tape, aux, all work fine. I get the white noise only on the left channel only when set to phono. The white noise goes up and down with the volume. I get the white noise with or without the turntable hooked up. Any help or suggestions would be greatly appreciated.
 
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Check solder connections on C104a (3.3uf/25V). Did you replace this cap?
What with?. Did you do any work on the opamp IC101 NJM2043? Should really
check solder on all replaced caps on phono stage. Maybe post a hi-res pick
of the phono stage both component and solder side.
 
I replace cap 104a with a 47uf/50v Nichicon cap. The original on my board was a 47uf. In an attempt to get rid of the white noise, I touched up all the solder on the phono board including on IC101. Other than that I did not do anything to IC101.
 
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I replace caps by removing them one at a time and replace with the same uf cap. That is what I did on this amp. However, the schematic shows a 3.3uf cap at 104a on the schematic. Replacing them one at a time with the same uf cap, I have a 47uf cap at 104a. I have 22 uf cap at 103a and 4.7uf cap at 113a. This is the way they were from the factory. Should I redo them and place them according to the schematic or leave them as they came from the factory. I played the amp for months without any issues till I recapped it.
 
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Looks like NJM2043 is in stock at Mouser for a whopping $0.96. Maybe it wouldn't hurt to replace it? Would it be possible to split the signal path somewhere and switch the channels? Maybe that could help isolate the problem component.
 
pcrosewood said:
Should I redo them and place them according to the schematic or leave them as they came from the factory.
Click to expand...
If they looked original then leave them as they are. Many errors
in schematics due to late production changes. I've an L-200 with same/similiar phono stage, it has 3.3uf cap at C104.
Importantly though, I don't see the difference between 3.3uf/47uf as being the source of white noise. The phono stage
is simple (=opamp), try replacing it, use a socket so you can easily make changes. Might even be like C105, some history
of those yellow caps going noisy.
 
Well, I tested every cap and resistor and diode in the phono stage and all good. I tested continuity of all the traces and all good I replaced the IC (2043DD JRC 2045) with one I had on hand (2043D JRC 8220) . That didn't work out, just got a lot of static from both speakers. So, do I need to replace the IC with the same numbers or are all 2043 IC's equal ?.
 
I will replace the op amp but must admit I don't know much about them. Can anyone recommend a good replacement ? The number on this one is 2043DD JRC 2045. So, am I looking for a 2043DD op amp or a JRC 2045 op amp? Any suggestions would be appreciated.
 
The opamp is JRC 2043DD also referred to as NJM 2043DD. The letters following the 2043 normally refer to packaging, D=DIP,
L=SIP etc,,, not sure about the second D??? Your replacement in post #12 didn't fix the issue, it shouldn't have made the
situation worse. Certainly install an opamp DIP socket so you can easily replace the opamps. The main feature/advantage
of the 2043 is its low noise. Sticking with the same company you could try NJM4580. The LM4562 is close noise wise but can
sound a bit dry while the OPA2134 can sound more musical (in my Kenwood Basic C1 at least). The 2043 is probably the best
in this case (don't know modern equivalent), also chaning opamps needs careful consideration of supply voltage and current
and should include frequency sweeps checking on an oscilloscope for oscillation etc...
 
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