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Amperex 6DJ8 ECC88 Bugle Boy Preamp Tubes Matched Quad - Holland 1964 - NOS

Amperex 6DJ8 ECC88 Bugle Boy Preamp Tubes Matched Quad - Holland 1964 - NOS

Regular price $266.00 USD
Regular price Sale price $266.00 USD
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Product Overview

The most popular tube at the Soundlumia store, the audio tube that every serious audiophile wants to own, and perhaps the most legendary 6DJ8 tube on the planet. They fly off the shelves faster than we can restock, but here we are again:  a very rare tightly matched quad of vintage 1964's Amperex Bugle Boy tubes made in Heerlen, Holland. 

Sound Qualities

As far as the tonality, there isn't much to say except that who doesn't love Bugle Boy? These are the tubes that defined the house sound of Amperex Heerlen - very detailed, great bass definition, extensive midrange and the right amount of warmth. Instruments sound very natural and vocal reproduction is over the top. The sound stage is spacious and well structured, and instrument separation is the best you can get in this price range.

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) and tightly matched on a reliable and recently calibrated Mercury 2000 tube tester with the following result (mutual conductance in uMhos and percentage of nominal):

Tube 1: 15,500/15,200 (123%/121%)
Tube 2: 15,800/14,800 (126%/119%)
Tube 3: 15,700/15,500 (126%/123%)
Tube 4: 15,400/15,500 (123%/125%)

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

We treasure this pair also because of the great cosmetic condition of all four tubes - over 85% of the paint is intact and well preserved. The Heerlen factory date code etched on glass are perfectly visible: 

delta 4J1 (delta = Heerlen, 4 = 1964, J = October, 1 = Week 1 of the production month) 
delta 4J3 (delta = Heerlen, 4 = 1964, J = October, 1 = Week 3 of the production month) 
delta 4G2 (delta = Heerlen, 4 = 1964, G = July, 2 = Week 2 of the production month) 
delta 4G3 (delta = Heerlen, 4 = 1964, G = July, 3 = Week 3 of the production month) 
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