Perfectly matched & balanced pair of vintage Philips ECC88 6DJ8 audio tubes - NOS - Heerlen, 1963 - Same date code - Very Rare

Sound qualities

What a great decade for the legendary Heerlen tubes! You get the "textbook" Philips/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.) To see how these sound differently from their German counterparts, please feel free to take at a look a wonderful pair of 1961's Siemens 6DJ8's we've recently sold here: https://www.ebay.com/itm/266281650331

Professional Sound Evaluation

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

Professional Tube Testing

Both tubes tested Strong NOS (110%+ nominal mutual conductance) on a Mercury 2000 tube tester with the following result (mutual conductance both in uMhos and in percentage of nominal):

Tube 1: 14,000/14,200(112%/114%)

Tube 2: 14,000/14,000(112%/112%)

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 stronger. 

Appearance & cosmetic condition

We treasure this pair for its near pristine cosmetic condition - nearly 100% of the paint is well preserved. The identical date code of Heerlen factory etched on glass is also perfectly visible on both tubes: delta 4B1 (delta = Heerlen, Holland, 4 = 1964, B = February, 1 = the 1st week of the month.) 

Shipping Policy 

 - Ship worldwide! Flat-rate economy shipping (USPS Ground Advantage) within the US. 

 - Same business day handling. Orders placed by 2:00PM US Pacific Time on weekdays are posted on the same day, otherwise the next business day. 

 - Combined shipping available - request invoice for total before making payment or receive shipping credit after order ships. 

 - Customers outside the US please pay extra attention: International shipping is through USPS Ground Advantage International by default. It's the least expensive option and customs declaration is automated but it may take longer than other carriers. If you prefer to use a different carrier please contact us first so we can get you the correct shipping rates before you make payment.

Return Policy - Please READ carefully

First of all, returns are acceptable as long as you are reasonable. Soundlumia sets extremely high quality standard for the products we deliver. Tubes we sell are guaranteed to work because we run professional tests and sound evaluation before they are approved for listing AND before we ship them to customers. So the "defective item" case doesn't exist and please do not bother trying - this type of returns will NOT be accepted without proof that tubes do not work and we will open a dispute with eBay. 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.) Please contact us to work things out before submitting return requests claiming "item is defective" or "item not as described." We would really appreciate your respect to the professional work we have done (sourcing, testing & matching tubes, evaluating tube sound, sharing our sound experience with you, packing and shipping) to make these wonderful vintage tubes available to you at reasonable prices.

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. No tricks here please. Abusive behaviors will be reported to eBay immediately and negative feedback will be left to your account - that's guaranteed. We have already reported several abusers and eBay has ruled in our favor the dispute cases. We are more determined than ever to continue working with eBay to help rid of these unprofessional, unjustified, unkind, unfair and unacceptable abuses that are detrimental to the eBay marketplace, the vintage tubes market and the audiophile community.