After his performing career ended, Cobb became fully focused on work as a record producer and sound engineer, which he had already begun doing by the Four Preps' breakup. He became involved with acts such as the Standells, the Lettermen, the Chocolate Watch Band, the Piltdown Men, Fleetwood Mac, Steely Dan, and Pink Floyd. Cobb also wrote songs for many of his acts, most famously 1966's "Dirty Water" for the Standells, 1964's "Every Little Bit Hurts" for Brenda Holloway, and 1965's "Tainted Love".
In his private life, Cobb was a champion horse breeder and, for a short while, served as president of the Idaho Racing Commission.
Cobb wrote, or co-wrote the following songs, most notably recorded by the artists noted:
- "Barracuda" – The Standells
- "Heartbeat" – Gloria Jones later covered by The Remo Four
- "Brontosaurus Stomp" – The Piltdown Men
- "Dirty Water" – The Standells
- "Every Little Bit Hurts" – Brenda Holloway, The Small Faces, Jimi Hendrix, George Clinton, The Spencer Davis Group, The Clash, The Jam, Alicia Keys
- "I'll Always Love You" – Brenda Holloway
- "No Way Out" – The Chocolate Watch Band
- "Sometimes Good Guys Don't Wear White" – The Standells, later covered by Minor Threat, The Outlets and The Vaccines
- "Tainted Love" – originally recorded by Gloria Jones in 1965 (it did not chart); significantly reworked by Soft Cell and released in 1981. It became a #1 hit in 17 countries and remains one of the most enduring pop songs of the 1980s