For preamp I agree it's great. The downside is when the battery runs out meaning that you should have either an extra battery just like for your DeWalt cordless drill or wall socket option.
I DIY-upgrade now my 30y old Classe 30 to work off the 24V automotive battery. A power 2-way switch will power up the battery when preamp is OFF and power ON safe battery charger. Contrary when the preamp is ON the safe battery charger is OFF. For listening session upto the whole day and night of charging will be plenty enough to run on pure battery power.
I DIY-upgrade now my 30y old Classe 30 to work off the 24V automotive battery. A power 2-way switch will power up the battery when preamp is OFF and power ON safe battery charger. Contrary when the preamp is ON the safe battery charger is OFF. For listening session upto the whole day and night of charging will be plenty enough to run on pure battery power.