(June 24, 2025) Coherent Source Service, an independent company dedicated to the service and restoration of legacy THIEL loudspeakers, has a new owner. Longtime industry veteran and friend of AV NIRVANA, Gary Dayton, has acquired the business from founder Rob Gillum, continuing the work Gillum began when THIEL’s original Kentucky-based operations shut down a decade ago.
If you’re a THIEL fan, Dayton’s name may already ring a bell. He joined THIEL in 2005 and spent the next eight years working across multiple departments—including service, training, sales, and new product development. He was originally trained by Gillum and later worked closely with Jim Thiel himself. Upon leaving, Dayton remained active in the audio industry and now returns to the role with a vast amount of experience and institutional knowledge.
Coherent Source Service, or CSS, has been up and running in Lexington, Kentucky, since 2018. The shop was originally created after THIEL’s Tennessee-era relaunch sputtered out and the company officially closed its doors. Gillum, who declined to relocate when the company left its longtime Lexington home in 2014, purchased THIEL’s remaining service inventory and equipment and built CSS into a self-contained business. For the past seven years, it’s served as a go-to destination for THIEL repairs, restoration, and parts support. With Gillum now entering retirement after 38 years of service, Dayton has stepped in to take the reins.
“Coherent Source Service can provide expert repair of nearly every speaker THIEL produced, and in most cases using original parts,” Dayton said. “CSS maintains new-old-stock of many original parts and has ongoing relationships with original suppliers that can still produce critical parts. In addition to an impressive parts inventory and active supply chain, CSS has critical assembly fixtures, testing facilities, and documentation that make it possible to restore THIEL speakers to original operating parameters. I am looking forward to working with enthusiastic clients from around the world. Our goal is to ensure that THIEL owners can happily enjoy their wonderful loudspeakers well into the foreseeable future.”
CSS continues to operate out of its Lexington facility—just a mile from THIEL’s original factory location—and maintains stock for nearly every THIEL model produced between 1977 and 2012. Services include repairs, maintenance, and restoration using original parts where available. The company also purchases and resells legacy models.
To contact Gary, reach out via email at gary (at ) coherentsourceservice.com or call +1 (859) 554-9790 (Monday through Friday, 9:00 AM to 5:00 PM Eastern).
For more, visit coherentsourceservice.com.
