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. Both tubes tested Strong NOS (110%+ 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: 13,500/14,100(108%/113%). Tube 2: 14,000/14,100(112%/113%). Good tubes start at 7000 and new tubes incl.NOS/NIB 12,500 - 13,000, and the Mercury 2000's rated mutual conductance (nominal) for new tubes is 12,500. 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.
We treasure this pair also because of the pristine condition of both tubes (clear inscription and clear date codes), which is amazing given the tubes' age. What makes this pair even more rare is the identical date code on both tubes: delta 4C1 (delta = Heerlen, 4 = 1964, C = March, 1 = Week 1 of the production month). Soundlumia sets extremely high quality standard for the products we deliver. Sound experience is a very subjective thing, and let's be real it's not that easy to run into compatibility issues between amps and tubes so that one won't fly, either. Secondly, if you are a tube roller looking to game the return system, Number One STOP.
We have seen it all and we know what you're up to.