BATTERIES: The batteries are optional and not required for AC operation. If you want to use batteries, consider the following:
TYPE OF BATTERIES - The O2 is intended to use Ni-MH “9 volt” (usually 8.4 volt rated) batteries. The Tenergy 8.4V batteries in the parts list are about 9.5 volts when fully charged and have 7 cells inside. There are also 6 cell (7.2 volt) and 8 cell (9.6 volt) batteries. While the 6 and 8 cell versions will sort of work, they’re not recommended. Alternately, you can also use disposable 9 volt alkaline batteries as you would in a Cmoy. Do not connect the AC power with Alkaline batteries installed (they’re not rechargeable).
INSTALLATION – Observe the correct polarity! It’s best to slide the board out and clip the batteries in place rather than trying to slide them in from the back of the case. You also need a small piece of foam or something similar to hold the batteries down against the board so they don’t come loose. Thin double sided foam tape to stick them to the board is also a good idea if you plan to leave them in a while. Loose batteries bouncing around inside could be bad! If your batteries are a bit shorter you may also need some sort of “shim” between the base of the batteries and the back panel to make sure they stay snapped in place.
RUN TIME - The default design with 250 mAH Ni-MH batteries has 7 – 9 hours of run time on a charge. The Low Power version uses more expensive low power op amps and has somewhat more (but still very likely inaudible) distortion but the run time is around 20 - 30 hours. See: Low Power. Higher capacity batteries in the 250 – 300 mAh range will extend the battery life with either version.
LOW BATTERY SHUTDOWN - The power control circuit in the O2 monitors the batteries and automatically turns the amp off if they drop much below 7 volts each. The amp will simply stop playing, or possibly cycle on and off, but the LED remains on to remind the user to turn the O2 off. Either way you should turn it off and charge the batteries as soon as possible.
BATTERY CHARGING - The batteries charge whenever AC power is connected with the O2 turned on or off. The charge current automatically tapers off as they reach full charge and you can leave the AC power connected indefinitely if you want. But if you’re going to use the O2 mainly as a desktop amp for months at a time you should remove the batteries. Charging time depends on how low the batteries are and which batteries are used but will generally be around 8 – 24 hours.
BATTERY SHELF LIFE - Most Ni-MH batteries have a significant self discharge rate. This means just sitting on the shelf with the O2 turned off the batteries are slowly dying. You can get “low self discharge” batteries that are significantly less prone to this problem. Just like an iPod or other portable player you should charge the O2 at least once a month even if you’re not using it. If the batteries are left dead for an extended time they may be damaged.
BATTERIES: The batteries are optional and not required for AC operation. If you want to use batteries, consider the following:
TYPE OF BATTERIES - The O2 is intended to use Ni-MH “9 volt” (usually 8.4 volt rated) batteries. The Tenergy 8.4V batteries in the parts list are about 9.5 volts when fully charged and have 7 cells inside. There are also 6 cell (7.2 volt) and 8 cell (9.6 volt) batteries. While the 6 and 8 cell versions will sort of work, they’re not recommended. Alternately, you can also use disposable 9 volt alkaline batteries as you would in a Cmoy. Do not connect the AC power with Alkaline batteries installed (they’re not rechargeable).
INSTALLATION – Observe the correct polarity! It’s best to slide the board out and clip the batteries in place rather than trying to slide them in from the back of the case. You also need a small piece of foam or something similar to hold the batteries down against the board so they don’t come loose. Thin double sided foam tape to stick them to the board is also a good idea if you plan to leave them in a while. Loose batteries bouncing around inside could be bad! If your batteries are a bit shorter you may also need some sort of “shim” between the base of the batteries and the back panel to make sure they stay snapped in place.
RUN TIME - The default design with 250 mAH Ni-MH batteries has 7 – 9 hours of run time on a charge. The Low Power version uses more expensive low power op amps and has somewhat more (but still very likely inaudible) distortion but the run time is around 20 - 30 hours. See: Low Power. Higher capacity batteries in the 250 – 300 mAh range will extend the battery life with either version.
LOW BATTERY SHUTDOWN - The power control circuit in the O2 monitors the batteries and automatically turns the amp off if they drop much below 7 volts each. The amp will simply stop playing, or possibly cycle on and off, but the LED remains on to remind the user to turn the O2 off. Either way you should turn it off and charge the batteries as soon as possible.
BATTERY CHARGING - The batteries charge whenever AC power is connected with the O2 turned on or off. The charge current automatically tapers off as they reach full charge and you can leave the AC power connected indefinitely if you want. But if you’re going to use the O2 mainly as a desktop amp for months at a time you should remove the batteries. Charging time depends on how low the batteries are and which batteries are used but will generally be around 8 – 24 hours.
BATTERY SHELF LIFE - Most Ni-MH batteries have a significant self discharge rate. This means just sitting on the shelf with the O2 turned off the batteries are slowly dying. You can get “low self discharge” batteries that are significantly less prone to this problem. Just like an iPod or other portable player you should charge the O2 at least once a month even if you’re not using it. If the batteries are left dead for an extended time they may be damaged.