VINTAGE 1962 MULLARD ECC83 / 12AX7 - BLACKBURN FACTORY - MADE IN THE UK - BRITISH VALVE ASSOC STAMP - VERY GOOD CONDITION

VINTAGE 1962 MULLARD ECC83 /12AX7 PREAMP TUBE, I63 ITERATION. MADE IN THE UK AT THE BLACKBURN MANUFACTURING FACILITY.

THIS TUBE HAS DATE CODE OF B2K3 VISIBLE IN THE FIRST FEW PICTURES. DATE OF MANUFACTURE IS 3RD WEEK OCT OF 1962.

THE TUBE IS USED AND SHOWS VERY LIGHT WEAR COSMETICALLY IN THE WHITE SCREEN WHICH INCLUDES THE "BVA" STAMP

TESTED NICELY ON MY MAXI-PREAMP 2 DIGITAL TUBE TESTER.

TEST SPECS ARE AS PICTURED AND AS FOLLOWS:

TUBE 1

GAIN A (Mu)          97.8  
GAIN B (Mu)          100.6

CONDUCTANCE (Gm) A 1389
CONDUCTANCE (Gm) B 1680

RMS NOISE A         -84.1
RMS NOISE B         -84.2

👉 Mullard ECC83 – I61 B2K3

Let’s decode it piece by piece.

🔍 What “I61” means (the important part)

• “I6” = ECC83 / 12AX7 tube type  
• “1” = first version of that design  

👉 So:

I61 = early Mullard ECC83 design

What that implies:

• Early 1960–1963 era
• Typically short plate, copper grid posts, halo (ring) getter
• Made at Mullard’s Blackburn factory (UK) in most cases  

💡 These are highly desirable—this is classic Mullard golden-era production.

🔍 What “B2K3” means (date & factory code)

Mullard used a second line code for:

• Factory
• Year
• Month/week

Breakdown:

• B = Blackburn factory (UK)
• 2 = 1962
• K = month code (October)
• 3 = week within that month

👉 So your tube was made:

🎯 October 1962 (week 3), Blackburn, England

This lines up perfectly with known I61 production runs 

🧪 What kind of tube you actually have

Putting it all together:

👉 You have a 1962 Mullard Blackburn ECC83 (I61)

Construction traits (typical for this exact code):

• Short gray plates (~14mm)
• Copper support rods
• Halo/ring getter
• Thick mica spacers

🎸 Tone (why people chase this exact tube)

The I61 Blackburn Mullards are considered one of the best:

• Rich, forward mids (classic “British” sound)
• Smooth highs (never harsh)
• Thick, musical overdrive
• Slight compression → feels “forgiving” in guitar amps

Compared to later I63:

• I61 = a bit warmer, thicker
• I63 = slightly cleaner/brighter

💰 Value (based on this exact code)

For a real I61 B2xx (1962 Blackburn):

• Used / strong: $120 – $200
• NOS / near NOS: $200 – $350
• Matched pair: $300 – $600+

Earlier codes like yours (1962) are especially desirable.

⚠️ One important thing

Because yours is:

• Correct format (I61 + B code)
• Correct era (1962)

👉 That’s a very strong indicator it’s a genuine Mullard, not a relabel.

(That etched code is basically the “fingerprint” collectors trust most.)

👍 Bottom line

You’ve got:

👉 A real-deal 1962 Mullard Blackburn ECC83 (I61)

👉 One of the most sought-after vintage 12AX7 types

REVERB "SAFE SHIPPING" INSURANCE INCLUDED. SHIPPING IS TO THE LOWER 48 STATES. SHIPPING TO ALASKA AND HAWAII WILL INCUR ADDITIONAL SHIPPING CHARGES.

THANKS FOR LOOKING.