Bzgl. Kopfhörter und Boxen habe ich Blackstar mal angeschrieben und die Antwort bekommen, dass es möglich ist Kopfhörer anzuschliessen ohne Boxen dran zu haben.
Es bleibt aber nicht möglich, den Amp ohne Boxen UND ohne Kopfhörer zu betreiben.
Siehe auch hier:
amp-blackstar-ht-5-head-review Post 30+ 31
Anbei die Anrowrt von Blackstar:
A:1. The emulated output is a mono output, but delivered via a stereo jack socket. This allows the use of either stereo headphones or mono recording outputs via the same socket (though the output is still in mono in the case of the headphones).
2. The emulated output is a low impedance output, and will drive headphones of any impedance. The low output impedance also allows it to drive the XLR input of a mixing console directly using a suitable jack to XLR lead, without the need to use a D.I. (direct injection) box.
3. The headphone output can be used with either mono or stereo jack and lead connections, without any adverse effects.
4. Plugging a jack plug (mono or stereo) into the emulated output socket of the HT-5 mutes the HT-5 power amplifier, and in this state it is safe to use the HT-5 without a loudspeaker plugged into the speaker output jacks of the unit.
5. If somebody is using the headphone/emulated output of a HT-5 without a loudspeaker speaker connected, and forgets to reconnect the loudspeaker before removing the jack from the headphone/emulated output socket, damage could occur to the HT-5 output stage. For this reason, we should only point out the possibility of using a HT-5 as a recording device without the loudspeaker connected, if the customer specifically asks about this point.