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AMIR
November 16, 2018 at 7:37 pm
Given this is DC coupled – is there any DC offset protection? Or any protection circuits beyond the muting relay to protect headphones from damage?
REPLY
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JOHN SEABER
November 16, 2018 at 10:10 pm
None present; we have shipped thousands of DC coupled amplifiers in the past similarly.
You can detect DC offset of any amp by listening for a large pop when changing gain, or severe noise when turning the volume potentiometer. If either happens, it’s a good idea to check your source for offset. We’ll add these suggestions to the Instructions guide. Thanks for your thoughts.
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I probably missed something inside the 33 pag. of this thread, but what opamps are in front of the LME49600? Are LME49600 as output buffers, right?
And what would be the roll of the opamp nearby the pot.?
I wonder because if JDS did the TI's recommended schematic for LME49600, then it has DC-servo, that means there should not much DC on outputs (probably 1mV or so).
However, in my my tests with rolling opamps in LME49600 amplifiers I realized that LME49720 is one of the few opamp where potentiometer is not becoming "scratchy". Instead, with lot of other opamps, potentiometer gets scratchy (tested with ALPS blue 10 KOhms pot.). So, wondering what opamps are inside JDS Atom, because I really think that swapping the 2 opamps from the gain stage might resolve this issue, especially if the "scratchy" noise happens only in the first 10-20 seconds after power ON.