HP Select Amperex 6DJ8 ECC88 Preamps Tubes Matched Pair Holland 1965 NOS
Perfectly matched & balanced pair of vintage HP Select Amperex 6DJ8(ECC88) audio tubes - Heerlen sound from 1965 - Super Strong NOS - Very Rare. Note: If you prefer the late 1950s' sound of HP Select Amperex, please check out our listing of a wonderful matched pair of 1959's HP Select Amperex 6DJ8 here. These are the legendary "medical tubes" made by Amperex Holland for Hewlett-Packard's medical devices distributed around the world.
Each tube had to go through rigorous test and selection processes designed, implemented and monitored by HP. What you get is the best from the best candidates in build quality and low noise. Manufactured and released only in limited quantity, these tubes are elusive to find and remain top choices of critical listeners and tube enthusiasts.
Despite the HP label, you get the "textbook" Amperex Holland midrange presentation that is transparent, natural and expansive, with a slight touch of warmth that illuminates your musical world. The top end is super airy, smooth and nicely extended like one would expect from the best Siemens tubes. Vocals are intimate, sweet and forward (but not right in your face) and that always reminds me how the vocals sound on the best Mullard tubes. Bass is deep and well controlled and the accuracy feels very similar to the high end German ECC88's Siemens, Telefunken. 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. 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 pair tested Super Strong NOS (120%+ nominal mutual conductance) on a Mercury 2000 tube tester with the following result mutual conductance in.Tube 1: 14,800/15,100. Tube 2: 14,000/14,800. Good tubes start around 7000 and new tubes incl. NOS/NIB 12,500 - 13,000, and 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 would 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 stronger. We treasure this pair also because of the great cosmetic condition of both tubes - over 90% of the paint is intact and well preserved. The practically identical Heerlen factory date codes etched on glass are perfectly visible on both tubes.Delta 5H2 (delta = Heerlen, 5 = 1965, H = August, 2 = 2nd week of the month). 5 = 1965, H = August. 3 = 3rd week of the month. Customers outside the US please pay extra attention. 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.
Soundlumia's founder is a seasoned sound professional who has advised orchestras and music studios in sound production in USA for over two decades, and "knowing sound" is the minimum skill requirement of our team.