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Philips Miniwatt 12AX7 ECC83 Matched Pair w/ Select Tube - Holland 1961 - NOS

Philips Miniwatt 12AX7 ECC83 Matched Pair w/ Select Tube - Holland 1961 - NOS

Regular price $192.50 USD
Regular price Sale price $192.50 USD
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Perfect matched & balanced pair of vintage Philips 12AX7/ECC83 audio tubes -  Holland 1961 - NOS - Super Rare

Product Summary

The "textbook Heerlen sound" has been referenced in several Soundlumia ECC83/12AX7 listings, and many tube enthusiasts asked what all that means. So here 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. And the pair presented in this listing is very special because one of the tubes has the lovely red birthmark, meaning it is a select tube that had gone through rigorous screening and noise tests.

Sound Characteristics 

The most distinctive sound feature of the Heerlen ECC83'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.) We would recommend these as an excellent choice if you are seeking the high end ECC83 tubes that can deliver the legendary Philips house sound flawlessly. 

Professional Tube Testing 

NO shorts, leakage or gas. NO noise or microphonics.

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

Tube 1: 1,050/1,000 (105%/100%)
Tube 2: 1,050/1,050 (105%/105%)

Good tubes start at 700 and new tubes (incl. NOS/NIB) 1,000, and the Mercury 2000's rated mutual conductance (NEW) for new tubes is 1,000. 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 tube's ability to amplify sound, so the higher these numbers the stronger. 

Appearance & Cosmetic condition

This pair stands out aesthetically among the vintage tubes. Although one tube has worn-off Philips logo and lettering, at least 90% of the silkscreen is well preserved on the other tube, and the identical acid-etched Heerlen date codes are perfectly visible on both:

delta 1L3 (delta = Heerlen, 1 = 1961, L = December, 3 = Week 3 of the production month)


This pair of tubes will be packaged in the NEW Philips reproduction tube boxes, secured by a handmade paper ribbon (by courtesy of Soundlumia.)
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