As a performing musician, and a longtime fan of the Echoplex and other tape manipulation tricks, I was immediately attracted to analog delay lines when they started coming out in the early 70's. There were several emerging brands and design techniques at the time, but the Reticon chips were hands down winners as far as ease of use, simplicity, and signal integrity. So the SAD-1024 was my chip of choice for several products for Paia. In later years, I used other Reticon chips for designs for A/DA and other companies.
The operation of a flanger is pretty straightforward, so there's nothing tricky about the design here. But, being a synthesis, I wanted voltage control of most of the functions within the circuit, so there are a variety of external control inputs on the rear of the unit.
I incorporated a case design similar to what John had used for the Gnome MicroSynth. Paia had not yet gotten into the manufacture of the stomp box enclosures ... that was Steve Wood's push when he did all the stomp box effects in the late 70's for them.
John suggested I prepare a manuscript for this unit and present it to Radio Electronics magazine, and I got a cover feature for the Phlanger in 1977, about a year after the product was released. That was a thrill for me after growing up reading John's and Craig Anderton's articles there.
The Radio Electronics cover feature for the Phlanger is available in my Publications archives here.
The 1500 Users Manual is in the Paia Documents archives here.