Here's FXDB's interview with Nils Carlin of Carlin:
How did Carlin start?
During my student years, late 60s-early 70s I used to know some musicians in my university town in south Sweden. I was keen on experimenting with electronics, and letting others try out my ideas (I was never much good as a musician myself). This led to my setting up a small business, distributing first via a friendly music equipment dealer in a nearby city, and later other shops in Sweden.
As far as I know, the phase effect was my own invention - others have come up with similar solutions, mostly later. And also usually with an oscillator to make a periodic effect. But controlling the phase effect with a pedal, as with a wah-wah was a bit different.
As for the compressor, the inspiration was perhaps negative - my music dealer showed me a pedal of another brand and asked me if I could make something better. Reverse-engineering the pedal, I decided to try - and felt I succeeded.
Where does the name come from?
It's my family name.
Why did you end production?
I had the business going for a few years in the early 70s, but there was no real future and little profit at the scale I could manage. I had to think about my studies and career.