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2x Mullard 12AX7 ECC83 - 14mm Short Ribbed Plates - Blackburn 1960 I61

2x Mullard 12AX7 ECC83 - 14mm Short Ribbed Plates - Blackburn 1960 I61

Regular price $214.00 USD
Regular price Sale price $214.00 USD
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Sound Sample:

Tube Summary

No other tubes can deliver vocals like the Blackburn Mullard's, and that's a fact. These ECC83's are extremely hard to find today and are becoming every serious audiophile's darling. Presented here are two lovely Blackburn valves with the old-style Mullard shield logo, which are even more special today.

Sound Qualities

The overall tonality of Mullard ECC83 tubes is warm and lively with a very spacious sound stage. "Like a warm British jacket of the finest tweed, these glorious tubes have an attractive sweet warmth in their midrange and lower regions."  This is how the experts on describe the sound signature of British-made Mullard tubes. The top end is silky and pleasant and doesn't get rolled off. They retain a fine sense of "air" at the top, and the upper midrange is smooth and liquid. These tubes reproduce the human voice, especially female voices, with haunting realism. The British made Mullard tubes are also known to have an attractive sparkle at the top with rich we know where that "warm British jacket" comes from!

Appearance & cosmetic condition

These tubes have nearly 100% of the paint and lettering remaining, and the identical Blackburn date codes are perfectly visible: 

I61 B1B (I63 = ECC83 short plate production gen #1, B = Blackburn, 1 = 1961, B = February)
I61 B1D (I63 = ECC83 short plate production gen #1, B = Blackburn, 1 = 1961, D = April)

Professional Tube Testing

NO short, leakage or gas. NO noise or microphonics.

One tubes tested Near NOS (90%+ of nominal mutual conductance) and the other Strong NOS ((110%+ of nominal mutual conductance) on a reliable Mercury 2000 tube tester with the following result (mutual conductance both in uMhos and in percentage of nominal): 

Tube 1: 850/980 (85%/98%)
Tube 2: 1,000/1,390 (100%/139%)

Good tubes start at 650 and new tubes (incl. NOS/NIB) 1,000 - 1,050, and the Mercury 2000's rated mutual conductance (nominal) for new tubes is 1,000. Test result can also be seen in the pictures. In case you wonder what all these numbers mean to your sound experience, it's actually quite straightforward: mutual conductance directly translates to a tube's ability to amplify sound, so the higher the numbers the better. 


This pair of tubes will be packaged in new white boxes.
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