JBL L300 Summit Speakers Pair – Restored – 1-Year Warranty

JBL L300 Summit 3-Way Speakers – 15-Inch Woofer – Pair

Professionally Restored by HQaudios - Inspected & Tested - Backed by Our 1-Year Warranty

1. KEY HIGHLIGHTS

• JBL L300 Summit 3-way floorstanding loudspeaker pair
• 15-inch JBL 136A woofer, LE85 compression driver on H92 horn / L92 lens, 077 ring-radiator tweeter
• Acoustic design derived from the JBL 4333 studio monitor
• 8-ohm nominal impedance, 150 W continuous program, crossovers at 800 Hz / 8.5 kHz
• Walnut cabinets with blue grilles
• All original drivers – cones and diaphragms in good condition
• Every driver checked, crossover capacitors checked, RTA-verified frequency response and phase
• Backed by our 1-Year HQaudios Warranty

2. PRODUCT OVERVIEW

The JBL L300 Summit brought the acoustic design of JBL's 4333 studio monitor into a home loudspeaker. Its 3-way system combines a 15-inch 136A woofer, an LE85 compression driver on an H92 horn with L92 acoustic lens, and a 077 ring-radiator tweeter in a bass-reflex enclosure.

The result is full-scale bass, a direct and dynamic horn-loaded midrange and an airy top end, housed in the distinctive Summit cabinet with its slanted front baffle and walnut finish.

We restored this pair with careful attention to technical operation and cosmetic presentation, while preserving the original JBL design and voicing.

3. HQAUDIOS RESTORATION & TESTING

Before Restoration

This JBL L300 Summit pair was carefully inspected upon arrival to evaluate its mechanical, electrical, and cosmetic condition.

Each cabinet, cone, surround, and spider was checked for originality and for glue joints that had loosened or shifted with age. Every driver was tested by hand for voice-coil rub, and the DC resistance of every driver was checked against its nominal impedance.

The crossover networks were examined for bulging or leaking capacitors, each capacitor was measured against its original value (within 10% tolerance), and the level controls were checked for burn marks or worn contact surfaces. The inspection results were used to determine the work required for this specific pair.

During Restoration

Based on the inspection results, this JBL L300 Summit pair was restored according to HQaudios' technical standards while preserving its original engineering and voicing.

• Presence & Brilliance L-Pads: Both original Presence and Brilliance L-pad level controls were carefully removed for internal inspection. The internal wiper contacts and resistive windings were found to be in good operating condition. Each L-pad was thoroughly cleaned, with special attention given to the internal contact surfaces to ensure smooth adjustment and reliable signal continuity.
• Drivers: All drivers retain their original cones and diaphragms, which are in good condition.
• Identification Label: To preserve its originality, the original JBL Summit L300 identification label was carefully cleaned using a specialized solution suitable for vintage printed surfaces.
• Cleaning & Detailing: All drivers, crossover boards, and terminals were cleaned, and the cabinets and grilles were cleaned and detailed.

After Restoration / Final Testing

Once restoration was completed, the pair underwent comprehensive testing under real operating conditions.

• Frequency Response: Measured with an RTA (real-time analyzer) and a calibrated sound card to confirm a smooth, well-balanced response and close matching between the two speakers.
• Polarity: Driver polarity was verified with a phase-reversal check so both speakers play in correct phase.
• Presence & Brilliance Controls: The controls were reinstalled and tested through their full adjustment range for consistent operation without unwanted noise or signal interruption.
• Listening Test: The pair underwent an extended real-world listening test with a wide range of music to confirm dynamics, tonal balance, and stereo imaging.
• Final QC: A complete visual and functional quality-control inspection was completed before release.

4. CONDITION

Technical Condition

• Drivers: All drivers operating; original cones and diaphragms in good condition
• Crossovers: Capacitors checked
• Presence & Brilliance L-Pads: Inspected, cleaned and tested through their full range; smooth, quiet operation
• Impedance: 8 ohms nominal

Cosmetic Condition

• Cabinets: Walnut cabinets with light signs of age
• Front Baffles: Dark front baffles with JBL horn/lens assembly
• Grilles: Blue fabric grilles
• Identification Label: The original JBL Summit L300 identification label remains intact and retains approximately 80% of its original cosmetic condition. The label shows normal age-related marks but remains clean, legible, and well preserved. The original model designation, system impedance information, and factory serial number remain clearly visible.
• Exterior Wear: The exterior shows light signs of wear consistent with age.
• Overall Presentation: A vintage pair with light signs of age and previous use. Please review all photos for exact cosmetic details.

Summary:

• Every Driver Checked
• Crossover Capacitors Checked
• RTA & Phase Verified
• Final Listening Test Completed

5. SPECIFICATIONS

• Brand: JBL
• Model: L300 Summit
• Type: 3-Way Floorstanding Loudspeaker
• Era: 1970s
• Low-Frequency Driver: 15-inch JBL 136A
• Midrange: JBL LE85 compression driver, H92 horn / L92 lens
• High-Frequency Driver: JBL 077 ring radiator
• Crossover Frequencies: 800 Hz / 8.5 kHz
• Nominal Impedance: 8 ohms
• Power Capacity: 150 W continuous program
• Sensitivity: 93 dB / 1 W / 1 m
• Dimensions: approx. 23 W × 31.6 H × 22.5 D in (each)
• Finish: Walnut / blue grilles

6. WHAT IS INCLUDED

• 1 pair (2) JBL L300 Summit speakers
• Blue front grilles shown in the photos

Only the items specifically listed above are included. Speaker stands or wood bases shown in the photos are for display only and are not included. Amplifiers, cables and other accessories are not included.

7. SHIPPING & PACKAGING

Your vintage audio equipment will be professionally packed by HQaudios using protective materials appropriate for its size, weight, and construction. Large or heavy items may be palletized and shipped by freight when required for safer transportation.

Please contact us before purchase for the most current availability information.

8. 1-YEAR WARRANTY & CUSTOMER SUPPORT

Your purchase is backed by our 1-Year HQaudios Warranty. Our team provides support before and after your purchase. If you have questions about setup, operation, compatibility, or your order, please contact HQaudios for assistance.