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 Systems Frequency Shifter is using Futura for its font, which I used for awhile before switching to the grotesk fonts I am currently using.
cool!Looks like the Deltalab color scheme. Is this unit tape based or BBD-based? (obviously not digital in 1975).
The 360 box is a frequency shifter, as opposed to a pitch shifter. These tended to use op amps for a phase differencing network, multiplier chips for the quadrature multiplication, and whatever clever little tricks they came up with for the quadrature oscillator. Hardware frequency shifters tend to be super complicated boxes.
I’ve ported my frequency shifter code to a small little DSP, the Spin Semiconductor FV-1, so theoretically this could fit in a stomp box. However, Electro-Harmonix came out with a frequency shifter / pitch shifter combo box recently, the Ring Thing, so I will stick with software for the time being. I wonder if the Ring Thing will do well, or if it will be one of those Electro-Harmonix boxes that bombs when first released, and becomes unbelievably collectible in the future.