RCA 12AU7 ECC82 Mullard Blackburn 1975 - Black Plates Halo-Getter

Title:

RCA 12AU7 ECC82 Vacuum Tube - Made by Mullard Blackburn UK - Gray Plate - GL Code

Description:

For sale is a premium vintage 12AU7 (ECC82) tube branded by RCA but manufactured by Mullard in Great Britain.

This is a classic example of "cross-branding" from the golden age of vacuum tubes. While it bears the orange RCA logo, the etched manufacturing codes identify it as a genuine Mullard production from the legendary Blackburn factory. These tubes are highly sought after by audiophiles and guitarists for offering the famous "Mullard warmth" at a better value than Mullard-branded equivalents.

Identification & Codes:

- Brand on Label: RCA

- Manufacturer: Mullard (Blackburn, UK)

- Tube Type: 12AU7 / ECC82 / CV4003

- Factory Code: GL (Mullard designation for 12AU7)

- Factory Location: Blackburn, Great Britain (Indicated by the 'L' code)

- Plate Construction: Gray plates

- Construction Era: Likely late 1960s to early 1970s based on branding and construction style

Why choose Mullard-made RCA?

RCA contracted Mullard to produce these tubes when domestic supply was tight. The result is a tube with the superior build quality and sonic characteristics of a British Mullard—known for a warm, rich midrange, smooth highs, and rigid construction that minimizes microphonics—labeled for the American market. It is widely considered a significant sonic upgrade over standard US-made GE or Sylvania gray plates.

Condition & Testing:

The tube appears clean with good glass clarity. The pins are straight and the internal structure is solid.

T1: 94%

T2: 92%

Sound Signature:

- Warm and musical midrange

- Smooth, non-fatiguing treble response

- Excellent durability and low noise floor

- Ideal for taming bright guitar amps or adding richness to Hi-Fi preamps

Quality Assurance:

We stand on Superior Service. All tubes are vetted on a Precision Model 612 tester for accuracy. If you are not satisfied with our supply, we will make it right.

Shipping:

We ship via USPS or FedEx within 1-3 business days from Superior, WI. Orders placed after 2:00 PM CST Friday ship the following Monday. International shipping available.

Returns:

Items are generally returnable within 30 days in original, as-shipped condition. The buyer is responsible for return shipping unless the item was not as described. Note: Please check the specific listing, as some vintage items are sold "As-Described."