September 28, 2012

• Tung-Sol USN 5687WA

  Tung-Sol was the first company to develop the 5687 tube and it was introduced in 1949.  The original version was tall (similar in size to a 12AU7) with black, ribbed plates and a square getter ring.  Tung-Sol 5687’s are generally considered to be the best of this type with a sound that is characterized as smooth, sweet, punchy and as having the most detail.

  The 1956 vintage subject pair was purchased as a set of four on April 1, 2005 for $66 at an Ebay auction and was not listed as NOS.  For comparison purposes, a basically identical pair of these tubes is currently being offered on Ebay by a Hong Kong seller for $39.  It would seem that I either overpaid seven years ago or, this type has appreciated at just about the inflation rate during the intervening period.  The review pair is a triple mica design, with smooth black plates, copper posts and a D-shaped (sometimes called a U-shaped or horseshoe) getter ring. 

    Tung-Sol USN 5687WA                                                                         The Pair
        

    Close-Up of D-Getter                                                                          Response Audio RAM Signature CD25
       
  

  
  I use tubes from the 5687/6900/7044/7119 family in my Music Hall CD25 disc player where they serve the function of Class A gain/output buffer.  The CD25 was sold c. 2003 by Response Audio and is technically called the Response Audio RAM Signature CD25.  The player started life as a Music Hall CD25 and was then extensively modified by Dan Wright’s company ModWright Instruments.  The stock tubes in this unit are cryo-treated Tung-Sol 5687WB of apparently identical construction.

  The Tung-Sol USN 5687WA replaced a pair of Philips Miniwatt SQ E182CC/7119 tubes (review forthcoming).  Many of my comments below are actually in direct comparison to both the Philips tube and the GE 7044.  My one pair of Bendix 6900 had one tube suffer infant mortality years ago.  I’ve never replaced the 6900 because they are virtually unobtanium and therefore very expensive, if you can find them.

   

  Listening Impressions:

  • Gain was lower than the Philips E182CC/7119 which makes sense since the Mu (amplification  factor) for a 5687 is 17 while the corresponding value for a 7119 is 24 (7044 = 21 and 6900 = 18.5).
  • Frequency response is more midrange-centric and classically “tubey” in nature.
  • The most holographic sound stage of any tube I’ve heard in this family.
  • Treble response is sweet with less of a leading edge to transients.
  • The antithesis of a “hi-fi” presentation resulting in a relaxed sound with the emphasis on the music rather than Technicolor effects.  The Breathless CD by Kenny G (okay, there’s no accounting for taste) never sounded more beautifully musical, smooth and sweet with evocative tone (so, I’m dating myself).
  • Switching output tubes in my Premier 140 from vintage Tung-Sol smooth grey plates to SED 6550C resulted in better extension at the frequency extremes, greater clarity and a more punchy sound as evidenced when listening to Twelve Tribes by Richard Souther.

   

  Depending on how your system is presently “voiced” and what your sonic goals may be, this Tung-Sol 5687WA may be just the ticket.  However, if you prefer your coffee black and nothing in your scotch except the glass it’s in, you may want to look elsewhere.  

   

  • 9:15 am
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