Vintage 1979 CTS 12" Horseshoe Alnico Speaker – 4 Ohm – Code 137-7946

Up for sale is a vintage 12-inch American-made Alnico horseshoe-magnet driver manufactured by CTS in late November 1979. This is an exceptional, heavy-duty piece of classic Indiana iron, ideal for vintage restorations, low-wattage tube amps, or custom cabinet projects.

Technical Bench Specs & Verification:

• EIA Factory Source Code: 137-7946 (CTS, 46th week of 1979)
• Impedance: Nominal 4-Ohm voice coil load (Measures right in the textbook 3.4 to 3.6 Ohm DC Resistance range on the bench meter).
• Magnet Architecture: Large-format vintage Alnico cylinder slug securely housed in a thick, heavy-gauge steel U-yoke/horseshoe channel.
• Cone Profile: Smooth paper cone body featuring a clean paper center dust cap and a flexible, treated roll compliance surround. The driver has been cleanly reconed/reconditioned in its past, moves completely freely, and has absolutely zero voice coil rub.

Sonic Profile & Application: Originally commissioned for high-end console stereos and organs to maximize solid-state amplifier wattage via a 4-ohm load, these large-yoke late-70s CTS Alnico frames are highly prized today by musicians. The smooth paper cone layout delivers a warm, velvety low-end, rich organic midrange, and smooth natural compression. It rounds off the harsh, ice-pick high frequencies common in modern speakers, making it an incredible drop-in upgrade for a vintage Fender Champ/Vibro Champ circuit or a boutique low-wattage 1x12 extension cabinet.

The factory stamping on the steel frame is incredibly faint but has been recovered and verified. The frame is structurally excellent, clean, and free of issues.