[solved] cheap replacement for LME49720?
Please marked as solved thanks
Hi,
Purchased a used soundcard, I need to troubleshoot why the outputs are very low volume .
A LME49720 forms pre-buffer for a discrete JRC4580 Headphone amp stage. There is no sound from this at all.
There is sound from front line out, but its barely audible (-100 gain).
I suspect a damaged LME49720 (socketed). Worse still, busted DAC.
Anyway I have some 2134 , are these suitable substitute? If not any suggestions?
Please marked as solved thanks
Hi,
Purchased a used soundcard, I need to troubleshoot why the outputs are very low volume .
A LME49720 forms pre-buffer for a discrete JRC4580 Headphone amp stage. There is no sound from this at all.
There is sound from front line out, but its barely audible (-100 gain).
I suspect a damaged LME49720 (socketed). Worse still, busted DAC.
Anyway I have some 2134 , are these suitable substitute? If not any suggestions?
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Ne5532. The 49720 basically supersedes it, albeit in plenty of cases there's nothing in between them.
Only concern is if this is in the i/v, where the gbw will affect response peaking.
But the 49720 is a $3 usd part, not back breaking to say the least.
Only concern is if this is in the i/v, where the gbw will affect response peaking.
But the 49720 is a $3 usd part, not back breaking to say the least.
I believe its DAC is voltage out. I have Ne5532 but soldered elsewhere in equipment. I guess I'll buy a new IC.
IF that doesn't work I'll have to sell it on to an unsuspecting buyer, like the last guy did :roll:
Thanks
IF that doesn't work I'll have to sell it on to an unsuspecting buyer, like the last guy did :roll:
Thanks
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In a prebuffer, provided no fancy compensation shenanigans around it, my bet is you can use the 2134, especially for testing. Heck an old TL072 would work so far as to check what burnt out and how.
Like I said I have 2134, this would be cheaper than buying new 49720 for troubleshooting alone. I'll check it out.
We don't "mark" anything as solved, since you started this thread the least you could do is explain what the problem was for the next possible victim.
If indeed it was nothing more than a bad chip it would be really nice and thoughtful to let the community know.
If indeed it was nothing more than a bad chip it would be really nice and thoughtful to let the community know.
Check the power supplies before you start swapping chips. Measure the voltage at each IC power pin with the card running. I can imagine a situation where the headphone amplifier is not powered, and it is loading the line out with a diode-like load, which will greatly attenuate and distort the line output. Shorted PSU regulator output caps can cause this and no chips may need replacing at all.
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