The most distinctive sound feature of the Heerlen 12AU7'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, structured and holographical. Bass is incredibly deep but well controlled and feels as accurate as on the high end German ECC82's (Siemens, Telefunken, Valvo Hamburg etc.) The stellar performance of foil d-getter takes all these wonderful sound qualities to a whole new level: instrument separation is super clean, detail retrieval is surreal, and it goes without saying that the extremely low noise on these tubes is to the vanishing point.
Professional Sound Evaluation
The tube 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: Handcrafted Bottlehead Crack Headphone amplifier
- Output: Neumann NDH 20 Closed Back Studio Headphones
Our full tube sound review was written 100% based on the actual listening experience while this tube was running in the system described above.
Professional Tube Testing
NO shorts, leakage or gas. NO noise or microphonics.
This tube tested NOS (100%+ mutual conductance value for NOS/NEW) on a Mercury 2000 tube tester with the following result (mutual conductance both in uMhos and in percentage of NOS/NEW):
3,020/3,000 (101%/100%)
Good tubes start around 2000 and new tubes (incl. NOS/NIB) 3,000, and Mercury 2000's rated mutual conductance (nominal) for new tubes is 3,000. 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.
Appearance & cosmetic condition
This tube is in pristine NIB condition. 100% of the paint is intact and well preserved. The Heerlen factory date code etched on glass is perfectly visible:
K64 delta 8E (K64 = 4th-gen ECC82 production, delta = Heerlen, 8 = 1958, E = May)
Packaging
This tube is packaged in the ORIGINAL Amperex 12AU7/ECC82 tube box (NIB.)
Shipping Policy
- US Shipping: Flat-rate USPS Ground Advantage
- International Shipping: (Please read carefully) USPS First Class International is used for all countries EXCEPT: Armenia, Chile, China, India, Latvia, Mauritius, Serbia, Slovenia, Tuvalu, and Vietnam. If you prefer to use a different carrier or shipping service, please contact us first so we can establish shipping rates before you make payment. If you are a buyer in one of the excluded countries, you must contact us prior to purchase to arrange shipping(USPS Priority recommended), or we may not be able to fulfill your order using standard shipping due to our concern of undelivered packages or shipping delays in your country.
- Same day shipping: 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.
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."
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 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.