[sdiy] Combined output / headphone jack?

[Mattias Rickardsson]

On Mon, 14 Oct 2024 at 22:09, Neil Harper via Synth-diy <
synth-diy at synth-diy.org> wrote:

> looks like the stereo output and headphones are being driven by the same
> circuit, NE5532's with 220 ohm series resistors. and if I understand the
> normalizing properly, the "shorting" situation I was worried about only
> happens if the LEFT/PHONES output is used with a TS cable without a
> cable in the RIGHT/MONO jack. even then there's still the 220 ohm series
> resistor in place so it's not even a short.. wonder if the 5532 would care?
>

On Tue, 15 Oct 2024 at 00:48, grant musictechnologiesgroup.com <
grant at musictechnologiesgroup.com> wrote:

> The Pro-One has a mono-for-stereo-headphones/audio output jack, again
> with the NE5532:
> Stereo headphones can be plugged directly into the AUDIO OUT jack. The
> headphones should have a minimum impedance of 600 Ohms,"
>

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.

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?

/mr
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