One Control (ワンコントロール) Minimal Series BJF Buffer This item takes only the BJF Buffer found in One Control switchers and puts it in a Minimal Series enclosure. It converts guitar/bass signals into a signal that is resistant to noise and attenuation without changing the gain. It features a phase inversion switch, which is great if your guitar isn't cutting through in a band setting; switching it can help it stand out. It's a simple and very easy-to-understand effect. The buffer itself shows signs of use, but there are no functional issues. There are tape marks.