This is an example of a non top-boosted JMI Vox AC-30/6 chassis from 1964. Four ECC83, one ECC82, four EL-84, and one GZ-34 rectifier tube make up the tube complement. Looking at the photo at the top of this page, the power transformer is located at left, the power supply choke is at center right, and the output transformer is at right. The locations of the transformers at either end of the chassis balances the weight of the chassis. The ingenious design of the JMI Vox AC-30 chassis combines an anodized steel horizontal base section and an aluminum vertical control section. The steel base of the chassis supports the power supply and output amp sections of the AC-30. The use of steel in the chassis base not only provides strength but also electronically isolates the high voltage (and hum producing) section of the power supply and output amp from the preamp area of the amp. The aluminum vertical section of the chassis supports the preamp circuitry and control panel. The use of aluminum for the preamp area offers several benefits. Aluminum is less likely than steel to pick up hum and oscillations from the power supply and output amp setion of the amp, further electronically isolating the preamp from the power supply. Aluminum is significantly lighter than steel, but it is not as strong. Brackets mounted to the top of the power and output transformers strengthen and support the upper area of the aluminum section of the chassis. The amplifier was neatly hand wired on tag strips. Top end WIMA "Tropyfol" capacitors were used throughout the preamp section. Even as these amps approach their fiftieth birthday, non-tube electronic failures in JMI Vox AC-30s are rare, a testimony to the high quality components used in construction of the amp. Removing the upper back panel of the cabinet exposes most of the circuitry in the amp for service convenience. The AC30 Treble amp pictured on this page feataured Celestion "Alnico Gray" speakers. The "Gray" is the same as the original "Alnico Blue," but in a new color. These early era speakers had wire terminals located in one of the lugs of the frame. Later versions of this speaker had speaker terminals mounted to a cardboard tag strip riveted to the frame. The picture at bottom left shows the speaker output terminal on the chassis. The red and black wires are connected to the 16 ohm output of the amp. Moving the red wire to the upper terminal connects it to the 8 ohm output. The entire chassis is mounted to a baltic birch plywood "slider board." Once the upper back panel is renoved from the amplifier cabinet, the chassis slides out of the cabinet like a drawer.