Cerwin Vega At40 Specs Fix

Cerwin Vega At40 Specs Fix

Note: Exact values can vary by production run and specific model/version. If you need model-year–accurate numbers, check the serial/tag or the official spec sheet.

Before you turn a single screw, you need the factory baseline. These specs are vital for finding replacement parts or recone kits.

General Information

The Drivers (The Critical Parts)

  • Tweeter: Cerwin Vega P/N 1302 (1-inch)

    • The Crossover Components

    The Cerwin Vega AT-40 is a vintage gem that rewards patient repair. By understanding the specific specs (10" woofer, 1" dome, 2.5kHz crossover) and executing the targeted fixes (re-foaming, ferrofluid swap, re-capping), you can resurrect these speakers to outperform modern bookshelf speakers costing $1,000+.

    Don't throw away your AT-40s because of a little foam rot. The fix costs about $50 in materials and one afternoon of your time. Once done, you will remember why Cerwin Vega earned the motto: “Loud is beautiful... if it’s clean.”

    Have a specific issue not covered? Check the voice coil resistance with a multimeter or inspect the cabinet for air leaks around the terminal cup.

    Disclaimer: Working with electronics and solvents requires caution. Always work in a ventilated area. If your voice coil is seized or your cabinet is water damaged, professional reconing might be required. cerwin vega at40 specs fix

    The original capacitors are 30+ years old. They "dry out," increasing ESR (Equivalent Series Resistance). This makes the speaker sound muddy and harsh.

    The AT40 Crossover Schematic:

    The Upgrade (Cost: ~$15) Buy Dayton Audio Polypropylene or Audyn Q4 capacitors.

    Soldering Process:

    Many original AT-10 (mistakenly called AT40) units suffer from a design oversight in the tweeter circuit: the factory 2.2 µF non-polar capacitor drifts high over time, causing the tweeter to receive low frequencies below 1,800 Hz. This leads to distortion and blown tweeters.

    Let's fix these. You will need basic soldering skills, a hex key set, and a foam surround kit.

    This is the most critical repair. Do not buy generic 10" foam; buy AT-40 specific foam (angled outer lip).

  • Glue the Surround:
  • Remove shims & Re-cap: Remove shims. Apply glue to the new dust cap and place it over the hole to seal the motor.