I just found an interesting link on the 360 Systems 20/20 Frequency Shifter: 360 Systems 20/20 Frequency Shifter (BODE) It gives a nice overview of how frequency shifters were used in some classic electronic music. Interestingly enough, the color scheme of the 360 Systems unit is very close to the ValhallaFreqEcho colors: This is pure coincidence, as I just found this post on Matrixsynth. The 360
![ValhallaFreqEcho and the 360 Systems Frequency Shifter - Valhalla DSP](https://cdn-ak-scissors.b.st-hatena.com/image/square/2edcded3194044e049a638879aabea2c57496a1e/height=288;version=1;width=512/http%3A%2F%2Fvalhalladsp.com%2Fwp-content%2Fuploads%2F2010%2F05%2F360freqshifter1.jpg)