JBL is one of the world's leading specialists in the design and manufacture of loudspeakers and audio systems, catering to both consumers and professionals.

The JBL SG 520E preamplifier and the JBL SE400 SE power amplifier were originally installed in the legendary JBL PARAGON, the brand’s iconic monolithic loudspeaker.

Released in 1963, the JBL SE400 SE amplifier introduced a major innovation with its T-type circuit design featuring a symmetrical power supply. Its output stage uses a “common collector” configuration, with a transformer providing symmetrical coupling to the preceding stage.

Two years later, in 1965, JBL introduced the SG 520E preamplifier—a futuristic device with a professional studio look. Together, they form an exceptional pair.

The SG 520E commands attention with its innovative design: a brushed aluminum front panel featuring only straight-line slide potentiometers for tone controls and balance, and illuminated push-buttons for input selection and power.

A standout feature of the front panel is a lower flip-down panel revealing advanced options, including:

• A microphone input

• Rumble filter

• Additional auxiliary inputs

• Low-pass filter

• Test signal generator control

• Monitoring switch

• Stereo recording output

• Five-level phono output selector

• 6.35 mm headphone jack

On the rear, the SG 520E offers great connectivity with:

• Two phono inputs

• A ground terminal

• MIC input

• Two AUX inputs

• Two tuner inputs

This particular SG 520E unit is missing its original wooden side panels and shows some visible wear and scratches on the front and top covers. The SE400 SE amplifier also lacks its original metal housing—one will need to be sourced or custom-made.

This rare and fully overhauled legendary pair will deliver hours of pure sonic bliss—a true delight for seasoned audiophiles.