2x Mullard CV5358 Mil Spec ECC88 6DJ8 Orig. Boxes Blackburn 1964/65 Strong

Technically equivalent to ECC88/6DJ8, the British military Mullard CV5358 tubes are the BEST choice if you want to hear even more refined version of the legendary Blackburn ECC88/6DJ8 sound. Like a warm British jacket of the finest tweed, these glorious tubes have an attractive sweet warmth in their midrange and lower regions. 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 human voice, especially female voices, with haunting realism.

Full disclosure from your peer audiophile: Mitcham E88CC's are my go-to tubes for listening to Maria Callas and Frank Sinatra and I refuse to use other tubes. Mullard's are also known to have an attractive sparkle at the top with rich bass... Now we know where that "warm British jacket" comes from! The pair worked wonderfully and sounded terrific in our professional studio setup for monitoring.

Input: Cambridge Audio CXC V2 dedicated CD transport + Schiit Audio Bifrost 2 Multibit DAC. Amplification: Liquid Platinum Tube Amplifier by Alex Cavalli. Output: Focal Clear MG Pro open-back headphones.

Our full tube sound review was written 100% based on the actual listening experience while this pair of tubes were running in the system described above. This set was tested and certified by RoeTest V11 tester with the following result. Tube 1 - GA2 B412. Measured transconductance (GM): 10.6/10.31 mA/V - 85%/82% (100% = 12.50 mA/V). Measured plate current (IA): 13.237/13.29 mA - 88%/89% (100% = 15 mA).

Tube 2 - GA2 B5G2. Measured transconductance (GM): 13.88/13.04 mA/V - 111%/104% (100% = 12.50 mA/V).

Measured plate current (IA): 16.74/17.377 mA - 112%/116% (100% = 15 mA). NO shorts, leakage or gas.

Curve trace is also included in the original RoeTest report. We treasure this pair also because of the pristine condition of both tubes - over 90% of the paint and lettering are well retained. The Blackburn date codes painted glass are also visible on both tubes.

(B = Blackburn, 4 = 1964, I = September, 2 = Week 2 of production month). B = Blackburn, 5 = 1965, G = July. 2 = Week 2 of production month.