Product Summary

The "textbook Heerlen sound" has been referenced in several Soundlumia listings of Amperex Holland 12AT7/ECC81 tubes, and many tube enthusiasts asked what that all means. So this is the answer: the late 1950s and very early 1960s tone, the beginning of over a decade's excellence in sound, the classic tonal template for all the great (and greater) Amperex/Philips/Valvo/Miniwatt tubes to be made in the years to come, the timeless Philips radio tone that many of us grew up listening to. 

Sound Characteristics 

The most distinctive sound feature of the Heerlen ECC81's is the transparent, natural and expansive midrange presentation, with a slight touch of warmth that illuminates your music. Every piece of music you play through these tubes sounds like from a vinyl record, whether your sound source is phono or not. The sound stage is spacious, deep and structured. Bass is incredibly deep but well controlled and feels as accurate as on the high end German ECC83's (Siemens, Telefunken, Valvo etc.) Thanks to the very rare foil d-getter on this pair, you get with fast response (as in the solid-state fast), overwhelming detail in sound and the realistic bass.

Professional Tube Testing 

Both tubes tested NOS  (100%+ nominal mutual conductance) on a reliable recently calibrated Mercury 2000 tube tester with the following results (mutual conductance both in uMhos and in percentage of nominal):

Tube 1: 3,500/3,600 (100%/103%)
Tube 2: 3,580/3,820 (102%/109%)

Good tubes start at 2,000 and new tubes (incl. NOS/NIB) 3,500, and the Mercury 2000's rated mutual conductance (nominal) for new tubes is 3,500. 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 these numbers the stronger. 

Appearance & cosmetic condition

Besides the world-class sound characteristics, we still treasure this pair for its near pristine cosmetic condition given the tubes' age - nearly 100% of the paint is still intact on both tubes, and the Heerlen date codes are perfectly visible on both tubes: 

Tk2 ⊿0 (Tk = ECC81, ⊿ = Heerlen, Holland, 0 = 1960) 

Packaging

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

Shipping Policy 


 - Ship worldwide! Flat-rate 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 First Class International Mail by default. It's the least expensive option but it may take longer than other carriers and tracking info may not be available in some countries after customs clearance. 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

Returns are acceptable if we made a mistake by delivering you wrong or defective products. Tubes we sell are guaranteed to work because we run professional tests and sound evaluation TWICE: 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 are faulty and we will open disputes with eBay. Sound experience is very subjective and we do NOT accept returns because you do not like the tube's sound signature or because you changed your mind about your purchase. Please contact us to work things out before submitting return requests claiming "item is defective" or "item not as described" or "just didn't like it" or "changed my mind."

 

Tube rollers abusing the return system will be reported to eBay immediately and negative feedback will be left to your account - that's guaranteed. We have already opened several dispute cases to report abusive buyers and eBay has always ruled in our favor. International buyers who request return or refund claiming your country's import duties or sales tax/GST/VAT are too high will be reported to eBay immediately for dishonesty and will be permanently blacklisted from purchasing from Soundlumia. We are committed to working closely with eBay to help rid the marketplace of dishonest, unjust, unreasonable, abusive buyers that are detrimental to the vintage tubes market and the audiophile community.