ssriram2791
100+ Head-Fier
This is excellent advice Andy ! That is why you are awesome !1. No, you don't need to wait for the amplifier to cool down, you can charge the C9 immediately after you stop playback.
2. Yes, the battery module is a power supply and QC3.0 18650 charger 2in1. you can charge your second set of battery in the battery module seperately.
3. Yes, and that's the whole point of allowing users to buy second battery module: facilitate non-stop (almost) playback. You don't need to cool down the amplifier, just plug in a fully charge module and continue your music session immediately.
4. Yes, you can have several set of 4x18650 batteries and swap them out anytime, the only requirements is to replace all 4 battery at the same time. Don't replace one or two batteries. You can do that with a torch but you must not do that with C9 because the battery are connect in series, not parallel. In fact, you can do this with any 18650 charger. I use three sets of 4x18650 batteries before the spare battery module are available separately. You can get a decent 4-slot 18650 charger at around $30, which is a lot cheaper if you don't want to swap the battery instantly like (3)
Be reminded when the chassis of C9 reached 50 degree C, it become uncomfortably hot to hold in your hand, but it is still a very safe operation temperature for the C9 circuitry. (and components).
I am getting XTAR VC4s 4slot 18650 charger from Orbtronic in addition to 8 orbtronic 3500 mAh batteries so that I can charge them and keep them in protective case and swap them out when needed.
I will be having some followup questions to ask on interconnects as well later today, though currently workung in office.
Thanks once again !