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<div dir="auto">Mixers often use 4 5532 opamps in parallel with larger resistors to give same drive current. A short will have no bad effect then.</div>
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<div class="gmail_quote">On 15 Oct 2024 13:23, Mattias Rickardsson <mr@analogue.org> wrote:<br type="attribution">
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<div dir="ltr">On Mon, 14 Oct 2024 at 22:09, Neil Harper via Synth-diy <<a href="mailto:synth-diy@synth-diy.org">synth-diy@synth-diy.org</a>> wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex; border-left:1px solid rgb(204,204,204); padding-left:1ex">
looks like the stereo output and headphones are being driven by the same<br>
circuit, NE5532's with 220 ohm series resistors. and if I understand the<br>
normalizing properly, the "shorting" situation I was worried about only<br>
happens if the LEFT/PHONES output is used with a TS cable without a<br>
cable in the RIGHT/MONO jack. even then there's still the 220 ohm series<br>
resistor in place so it's not even a short.. wonder if the 5532 would care?<br>
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<div dir="ltr" class="gmail_attr">On Tue, 15 Oct 2024 at 00:48, grant <a href="http://musictechnologiesgroup.com">
musictechnologiesgroup.com</a> <<a href="mailto:grant@musictechnologiesgroup.com">grant@musictechnologiesgroup.com</a>> wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex; border-left:1px solid rgb(204,204,204); padding-left:1ex">
The Pro-One has a mono-for-stereo-headphones/audio output jack, again<br>
with the NE5532:<br>
Stereo headphones can be plugged directly into the AUDIO OUT jack. The<br>
headphones should have a minimum impedance of 600 Ohms,"<br>
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<div>As you have pointed out, the signal on the ring will need to handle being permanently shorted to ground if a TS plug is connected.</div>
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<div>Many typical headphones will be around 100-200-300 ohms. Feels a bit underspecified to use an op-amp with 500-1000 ohm load capabilities here, perhaps worth making a proper headphone stage for these outputs?</div>
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<div>/mr</div>
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