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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Yes the OPA1678 has a higher drive current than the 5532, but using both of the pair of a 5532 in parallel works out cheaper than half a OPA1678 per channel
provided you don’t mind the 4 times quiescent current (2* per opamp and 2 opamps).
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Noise and distortion are very similar, and far below what is audible.<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Synth-diy [mailto:synth-diy-bounces@synth-diy.org]
<b>On Behalf Of </b>Martin Klang<br>
<b>Sent:</b> 08 September 2021 17:49<br>
<b>To:</b> synth-diy@synth-diy.org<br>
<b>Subject:</b> Re: [sdiy] headphone driver for synths<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p>What about just using an op amp with higher current capabilities, like<o:p></o:p></p>
<p>TS922: Rail-to-rail input and output, Low noise: 9 nV/√Hz, High output current: 80 mA (able to drive 32 Ω loads)<o:p></o:p></p>
<p>or for split rails maybe the OPA2990?<o:p></o:p></p>
<p>For line level outputs that should also cope with headphones (as opposed to dedicated hp outs) I've been using OPA1678 which I think can output 50mA. Have I been doin' it wrong?<o:p></o:p></p>
<p><o:p> </o:p></p>
<p>Martin<o:p></o:p></p>
<p><o:p> </o:p></p>
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<p class="MsoNormal">On 08/09/2021 15:07, Mike Bryant wrote:<o:p></o:p></p>
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<p class="MsoNormal">You can trace that design back to at least Wireless World's around 1974, probably a bit earlier.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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