The 5R4 Rectifier

The 5R4. The 5R4 is a hefty rectifier that you see in a lot of industrial equipment, particularly the USAF stocks. Here we have an early RCA, a GE, a Philips 5R4GYS which has been all the rage lately, and finally two massive “potato masher” 5R4WGB tubes made for the US Air Force by Bendix and Chatham. All of these are good sounding tubes. Spec sheets for the 5R4 can be found here: here.

The 5R4. A closer look at the Bendix and Chatham 5R4WGB. Talk about overbuilt. These feature thick glass and robust everything, but for some reason pretty much all of these seem to have tilted glass.