Amperex Holland/Philips 7316 ECC186

The "textbook Heerlen sound" has been referenced many times in Soundlumia’s tube sound reviews for ECC82, 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.  

But there's also a "secret" version of the textbook Heerlen sound that very few have heard: ECC186 (aka 7316 or 12AUWA) tubes made in Holland (and ONLY in Holland.) As an improved version of ECC82 tubes designed for computers, ECC186 has a special cathode that allows the tube to be operated without anode current for long periods of time without damage. Remember the last time you heard people talking about the elusive "circuit tubes?" You are looking right at them! It would be fascinating to understand the technicality as to how this special design had made the Heerlen sound so amazing, but our audiophile ears perhaps only care to know this is Amperex Holland's official answer to Telefunken's ECC802S and Mullard's 10M Master Series. In other words, these tubes compete and ONLY compete in the Holy Grail league of the ECC82 family. 

The most distinctive sound feature of the Heerlen tube sound 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 it is 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 ECC186, whether it is d-getter or o-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 noise on these tubes is to the vanishing point. 

Professional Sound Evaluation

Tube 1:

Measured transconductance(GM): 2.06/1.89 mA/V  - 94%/86% (100% = 2.20 mA/V)

Measured plate current(IA): 10.817/9.52 mA  - 103%/91% (100% = 10.5 mA)

Tube 2:

Measured transconductance(GM): 1.99/1.84 mA/V  - 90%/84% (100% = 2.20 mA/V)

Measured plate current(IA): 9.295/8.665 mA  - 89%/83% (100% = 10.5 mA)