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DIY For Audio
Looking for some advice re fixing an old Pioneer C-4500
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<blockquote data-quote="marantz123" data-source="post: 949239" data-attributes="member: 16849"><p>I would clean all the switches (tape/loudness/filters/selector etc. again as a first step. Next, is the "distortion" like a soft frying or soft " rain" sound that is constantly in the background ? If so, assuming that this is a fully discrete design, check the schematic to see what the phono and main preamp transistor line up looks like. Some Jap small signal transistors are known to be problematic, one that comes to mind is the 2SC458. The pn junctions in these become leaky and iirc were not hermetically sealed. With age, one of the symptoms are a soft rain sound as explained above. If they are in there, consider replacing them with a modern, similar component. I have tried a few different transistors as the recommended drop-in substitution for the 458, but used BC546B transistors instead as I was quite impressed with them, but note the pin-out is different so some consideration needs to be given here.</p></blockquote><p></p>
[QUOTE="marantz123, post: 949239, member: 16849"] I would clean all the switches (tape/loudness/filters/selector etc. again as a first step. Next, is the "distortion" like a soft frying or soft " rain" sound that is constantly in the background ? If so, assuming that this is a fully discrete design, check the schematic to see what the phono and main preamp transistor line up looks like. Some Jap small signal transistors are known to be problematic, one that comes to mind is the 2SC458. The pn junctions in these become leaky and iirc were not hermetically sealed. With age, one of the symptoms are a soft rain sound as explained above. If they are in there, consider replacing them with a modern, similar component. I have tried a few different transistors as the recommended drop-in substitution for the 458, but used BC546B transistors instead as I was quite impressed with them, but note the pin-out is different so some consideration needs to be given here. [/QUOTE]
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DIY & Tutorials
DIY For Audio
Looking for some advice re fixing an old Pioneer C-4500
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