“This is an excellent and needed upgrade for the AC-33 Roland acoustic guitar amp.
Although the existing battery 8xAA works well it has two issues.
The first is that the amp output is reduced by one-third when batteries are used 15W stereo RMS x2 = 30W to 10W stereo RMS x2 =20W. This reduction in output is noticeable especially in an outdoor busk session or a room venue that is larger than small.
The second is that rechargable batteries have to be recharged of course (or you use diposable batteries), and keeping 8 batteries recharged is a hassle, and rechargable batteries can't be recharged while fitted into the amp and connect to wall power, you have to do them individually in a recharging unit.
The BTY pack fixes both these problems giving near to full power and SPL output, and the unit can be recharged while fitted into the amp. Also Roland reports that the pack lasts double the time of 8xAA batteries although I haven't tested that myself. You can't play through the amp while recharging, but you can simply connect the power supply to the power input and use the amp. Also, the BTY does not require a separate cable it uses the existing PSU plug.
The build quality is excellent and it is a perfect fit into the existing battery module cavity. It sticks out a bit but I haven't found that to be a problem. An additional benefit is that you can use the battery pack to store 8xAA batteries and use it as an emergency backup should the BTY go flat.
A thoroughly recommended addition to the excellent AC-33.”
