Any of you heard of a singer named Rita Coulidge? The first Rita Coulidge song that I heard was a song called “We’re All Alone.” Almost from beginning to end, there’s this melodic, yet resonant synth line.
Do those of you that have heard this song know how that was done? It originally sounded to me like an ARP Odyssey, but I thought the same thing of Steve Winwood’s solos on “While You See A Chance,” “Valarie” and “The Finer Things,” all of which were done with a Minimoog. 
The tell tale sign may be the filter, but my ear isn’t fine-tuned to distinguish between Moog and ARP lowpass filters, like many other people.
Could someone help me out?
Eric.