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Amperex PQ 6DJ8 ECC88 Preamp Tubes Matched Quad - Holland 1972 - Same code -NOS

Amperex PQ 6DJ8 ECC88 Preamp Tubes Matched Quad - Holland 1972 - Same code -NOS

Regular price $278.00 USD
Regular price Sale price $278.00 USD
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Tube Summary

Enjoy the most musical 6DJ8/ECC88 tube on Earth - Amperex 6DJ8 PQ (Premium Quality) made in Holland from the early 1970s! PQ tubes are among the greatest Amperex tubes ever made and are highly sought after by serious audiophiles. These prestige tubes were made with special filament technique to produce special quietness in sound - something one can only find on Philips SQ (Special Quality) or high-end German E88CC tubes. 

Sound Characteristics 

As a major step-up of the famed early production of Amperex Holland tubes with steel pins (Bungle Boys, Orange Globe etc.), these tubes combine the best of both worlds: the large sound stage, transparent midrange and liquid & harmonic sound from the Bugle Boy & Orange Globe, and the laser precision imaging and superb smoothness in the top end from the PQ series. We have recommended PQ tubes to so many satisfied customers who use them in their phono setup that we have given them a nick name "sound purifier" - the sound that comes from these tubes has absolutely no edginess, glassiness or harshness, and you hear nothing but the soul of your music and all of it. These are the best tubes to to put in the phono stage to "purify" your sound.

Professional Sound Evaluation

The quad was split into two matched pairs, both of which 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 these tubes were running in the system described above.

Professional Tube Testing 

All four tubes tested Super Strong NOS (120%+ nominal mutual conductance) on a Mercury 2000 tube tester with the following result (mutual conductance in uMhos and percentage of nominal):

Tube 1: 15,400/15,300 (123%/122%)
Tube 2: 14,250/14,000 (114%/112%)
Tube 3: 14,100/14,800 (113%/118%)
Tube 4: 14,500/14,900 (116%/119%)

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 tube's ability to amplify sound so the higher the numbers the stronger. 

Appearance & Cosmetic condition

This quad is so rare because nearly 100% of the paint is intact on all the four tubes, and they share the same exact Heerlen date code:

GAE ⊿2L2 (GAE = control code for 1970s, ⊿ = Heerlen, Holland, 2 = 1972, L = December, 2 = Week 2 of the production month) 


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