Mullard GE 12AX7/ECC83 1966 - Nice labled Glass

Vintage Matched Quad of General Electric (GE) Branded Mullard 12AX7 / ECC83 Tubes

Blackburn Factory Short Plate I63 – 1966 Date Codes – Excellent Tested Condition

Up for sale is a beautiful matched quad (set of 4) of genuine Mullard Blackburn 12AX7/ECC83 preamp tubes, rebranded for General Electric. These are highly sought-after by guitarists and audiophiles for their warm, harmonically rich tone with excellent sustain and compression — perfect for Marshall, Vox, Fender, and hi-fi preamps.

Key Details:

•  Etched codes: I63 B6K (Blackburn factory, 1966 production — all very close date codes)

•  Construction: Classic short grey plates, halo (O) getters, made in Great Britain

•  Tested on Precision 10-12 tube tester:

•  Tube 1: 70/100  •  72/100

•  Tube 2: 72/100  •  75/100

•  Tube 3: 78/100  •  80/100

•  Tube 4: 80/100  •  85/100
All sections strong and well above “good” levels with solid balance.

These tubes show typical light wear for their age but are clean overall with clear etchings and intact labels (see photos). No major cosmetic issues, excellent pins and bases.

Why these are desirable:

•  Authentic UK Mullard Blackburn production (the “gold standard” for many players)

•  Close date codes for good matching

•  Strong emissions — ready to drop into your amp

•  Far superior tone to modern reissues