Hi Im hoping someone can help me with this problem, a month ago I replaced the stock ICs in my Marantz CD67 CD player with 8 pin DIP sockets and a pair of LM4562. The result was very disappointing it generated loud consistent hissing, the level of the noise was more than the music, I received a second pair yesterday and they worked perfect.
Id like to know before jumping to any conclusion if there could be such a wide discrepancy between two different batches of LM4562 to make on unlistenable while the other works so well. And if so what do do to make the other pair usable.
Thanks
Id like to know before jumping to any conclusion if there could be such a wide discrepancy between two different batches of LM4562 to make on unlistenable while the other works so well. And if so what do do to make the other pair usable.
Thanks
When the LM4562 first came out, I ordered 3 engineering samples from Nat Semi.
I only needed two (for my CD67SE too!) but got a spare too.
Good job I did as one of them behaved exactly as the OP described.
When I switched the channels, the problem followed the bad op-amp.
The decoupling/bypassing was solid, and I had no such problems with LM6172 and AD8065x2 for example.
I didn't much care for their sound anyway - too sterile for my tastes. Went with AD825x2 on Brown Dogs in the end (although LM6171+OPA627 worked particularly well also).
I've since tried the LM4562HA (the ones with the metal hats) as people said they sound totally different. They did sound a bit different, still crap though. YMMV.
I only needed two (for my CD67SE too!) but got a spare too.
Good job I did as one of them behaved exactly as the OP described.
When I switched the channels, the problem followed the bad op-amp.
The decoupling/bypassing was solid, and I had no such problems with LM6172 and AD8065x2 for example.
I didn't much care for their sound anyway - too sterile for my tastes. Went with AD825x2 on Brown Dogs in the end (although LM6171+OPA627 worked particularly well also).
I've since tried the LM4562HA (the ones with the metal hats) as people said they sound totally different. They did sound a bit different, still crap though. YMMV.
Yesterday I made a unity gain buffer circuit to test if they were only unstable in the CD67, turns out they worked in test circuit, no hiss this time but they sounded bloated compared to the other sets.
maybe they were just a bad batch lucky me. The good ones sounds great by the way.
thanks for your replies
maybe they were just a bad batch lucky me. The good ones sounds great by the way.
thanks for your replies
I had an unlistenable OPA2132 once...
As for their sound, in stock player they sound boring even with good caps, I like more even the JRC! Then with 137/337 regs it starts to sing a lot better. Maybe with super regs it's even better? Need a very nice dynamic "pre-opamp CDP" before them...
As for their sound, in stock player they sound boring even with good caps, I like more even the JRC! Then with 137/337 regs it starts to sing a lot better. Maybe with super regs it's even better? Need a very nice dynamic "pre-opamp CDP" before them...
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