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Blackburn UK production !
Last month I was able to buy six Mullard ECC83 that were still in their original packaging. The tubes were individually wrapped in a protective cardboard and a warranty form (see photos). It was a magical moment to get them out of their wrap since their production in the 60s!. These tubes are therefore absolutely unused.
This early pair ECC83 is by Mullard in1965 in Blackburn UK (version I63). The tubes bear the old Mullard logo. The tubes have a halo getter on ‘copper’ post and ribbed grey plates, see pictures. Matched tubes with balanced systems; see test results.
Sonics
The I63 version of Mullard is known as a very fine ECC83; with a liquid, creamy and very detailed sound image. I refer to the many threads on the web for more information. Excellent preamp valve, very low noise, very smooth extended highs, very good in phono stages. Balanced and smooth sounding with liquid midrange, recommended!
Note from the web: “The overall tonality of Mullard Mitcham 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 audiotubes.com 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 bass…now we know where that “warm British jacket” comes from!
Note: if your system is to “warm sounding’, this tube is not a first choice. Philips Holland made ECC83 tubes are to be considered in that situation.
The pair is thoroughly tested and has excellent test values that match the factory specifications of a new tube very well and both tubes have balanced systems. See test results below.
Test method & results
The tubes have been tested carefully with the official Telefunken test set-up and our sophisticated test equipment. Please read our testmethod for the ECC83 tube family. The measurement data below show that these tubes are matched to each other and are internally balanced. And meet the factory specifications of a new/NOS tube.
| Valve 1
V390 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
1,2 / 1,2 mA
1,8 /1,7 mA/V OK |
= NOS / NOS
= NOS / NOS
|
| Valve 2
V391 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
1,3 / 1,3 mA
1,8 /1,8 mA/V OK |
= NOS / NOS
= NOS / NOS
|
Where NOS is : Ia = 8,7 to 12,5mA, Gm= 1,9 to 2,7 mA/V. Ia = 10,6 ± 1,9 mA. (Telefunken factory specification see test page)
Short description
| Tube type | ECC83 (I63) |
| Quantity of Tubes | One pair |
| Brand | Mullard |
| Manufactured in | Blackburn UK |
| Dates | 1965 ( I63 B 5K3 & I63 B 5K5) |
| Construction | Ribbed grey plates, copper grid posts |
| Getter Construction | Halo getter on ‘copper‘ post |
| Print Condition | See pictures |
| Box included | Original Mullard with warranty form included |
| Equivalent tubes: | 12AX7, ECC803S, CV4004, 12AX7WA, E83CC |
| General test results | NOS |
