An important source for rebuilt power tubes is going away.
Microwave Power Products plans to close operations at the former Econco facility in California, ending its program for rebuilding the tubes used in vacuum tube-type transmitters, as our Nick Langan reported last month.
MPP said operations at the Woodland manufacturing site will cease on Sept. 1 as it consolidates operations to Palo Alto. As part of the transition, the company will discontinue repair services for Econco Power Grid tubes, though it will continue to manufacture new tubes.
The move also ends Econco’s “bank” program, which allowed customers to store non-working power grid tubes at the Woodland facility to be rebuilt and made available for future purchase.
The deadline to purchase repaired Econco Power Grid tubes is May 12 at close of business. According to the release, failure to confirm a purchase or request the return of non-working tubes by that date will be treated as consent for MPP to dispose of property remaining in the Bank program.
According to a timeline on MPP’s website, Econco was founded in 1968 and held the first contracts awarded by the U.S. government and the U.S. Navy to remanufacture microwave devices, twice receiving the Navy’s Award for Excellence.
Communications & Power Industries acquired Econco in 2004. In June 2024, Microwave Power Products Inc. and the CPI Electron Device Business spun off from CPI to become an independent entity.
As Nick wrote in his story, the development is significant for stations using transmitters that require tubes such as the EIMAC 4CX20000E.
“Several readers have expressed concern regarding the dwindling number of companies offering rebuilt power tubes, which provide a cost-effective alternative to purchasing new tubes, or a solid-state transmitter,” he wrote.
Massachusetts-based Kennetron advertises vacuum tube rebuilds. And some readers have inquired about options on Alibaba, including those from Chinese manufacturer Jingguang, though some expressed concerns about sourcing from China including reliability and import tariffs.
Dave Morgan is the director of engineering at Sinclair Telecable in the Hampton Roads region of southeast Virginia. Among his properties are two AM sites using tube-type transmitters and a Gates/Harris FM model (which our own John Bisset sold him some 27 years ago).
“These are excellent transmitters when properly operated, maintained and understood,” Morgan told us.
The Econco closure, Morgan said, was a major development.
Vacuum power tube technology is proven and still somewhat reliable, he said, though less efficient than solid-state. He has observed over the years that Gates/Harris, Collins/Continental and Broadcast Electronics built their tube transmitters to last.
Morgan acknowledged that some engineers have reported quality control or lifespan issues from rebuilders in recent years.
“I understand that the power tube rebuilders and manufacturers might be having a harder time nowadays sourcing elements like tungsten and thorium,” he said.
But Morgan’s Sinclair properties — no relation to the large Sinclair Broadcast Group — have had no significant problems with rebuilt tubes over the decades.
His stations follow the rebuilder’s break-in procedures to the letter, paying close attention to filament voltages, aiming for proper tuning, monitoring stack temperatures and keeping the ambient air inside the transmitter buildings clean, cool and dry.
“Like everything else after 2020, the costs for tube rebuilding shot up,” Morgan told Nick. As a result, the cost for brand-new tubes followed suit.
Links to Nick’s stories are below:
