September 2, 2012

• Philips ECG 6550 ST Shape

  The subject of this review is the Philips ECG 6550 ST shape output tube.  It has a three hole, grey plate structure with a top getter and two side getter rings positioned near the center of the plate structure.  Six tubes of the set have a brushed gold colored collar and the remaining pair have a shiny chrome colored collar.  All of them have a black base which is typical of later production output tubes.  Although not dated, I believe these were most likely produced sometime during the 1980s.

  The set was well broken-in and was auditioned over a period of 39 hours.  They replaced the previous set of SED =C= 6550C power tubes which still remain my current favorite in the c-j Premier 140 amplifier now that it's had the Teflon capacitor upgrade.

   

  Packaging Sleeve Marked Sylvania ECG                                                    Front View  (chrome collar)
       
  

  Rear View (chrome collar)                                                                      Close Up of Plate Structure
       
  

  Brushed Gold Collar
  
  

   

  Listening Impressions:

  • The Four Seasons CD featuring Trevor Pinnock and the English Concert revealed borderline excellent detail with the solo violin having nice leading edge transients but lacking the pleasant "bite" heard with the SED 6550C.
  • The sound stage was more distant than the SED 6550C with dense images occupying their own acoustic space.
  • Wooden blocks were a bit muted although vibrato on vocals was clearly rendered.
  • When the XLO Signature 5.1 speaker cables were introduced into the system, their deep, solid and well articulated bass came through unhindered.
  • Dynamic swings were excellent as was evidenced on The Film Music of Jerry Goldsmith SACD.
    
  • Changes made to the system involving tube dampers and footers were readily apparent and repeatable.

  These are excellent tubes although increasingly difficult to source nowadays, as is the case with many vintage output tubes in the 6550 family. Fortunately, the SED =C= 6550C comports itself very well (at least in my current application) and in my opinion, is actually superior overall.

   

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  The following has been added subsequent to the above post.

  Some readers may have noticed that I did not discuss the country of origin for the Philips ECG 6550.  This is simply due to the fact that I'm not sure where they were made.  The Sylvania ECG Electronic Tubes sleeve in which four of the tubes were purchased reads the following on its bottom:

  Philips ECG, Inc.
  Waltham, MA 02254
  A North American Philips Company

  So we can probably say with some confidence that these tubes were distributed by Philips but not with any certainty can we say where they were made, or when for that matter.  No place on the tubes themselves is there any indication of either.  

  I'd like to thank the Triode, USA web site for the following information regarding the vagaries surrounding these tubes and others from this time period:

  In the 1970's GTE reorganized Sylvania into several "groups", the Lighting Group, the Consumer Electronics Group, and the Electronic Components Group. Thus , Sylvania tubes began carrying the "Sylvania ECG" logo, ECG meaning Electronic Components Group. Sylvania was a large supplier of all types of replacement electronic components to electronic distributors at the time, including both tubes and transistors.Its successor, Philips ECG, still is.

  About 1980, some weird transactions took place. Philips got tired of making tubes in Europe, and its Amperex subsidiary wasn't doing too well, so they sold off their English & Dutch tube making assets and the rights to the Mullard & Amperex brand names to Richardson Electronics of La Fox, IL, and withdrew the license to use the Mullard brand name from International Electronic Components of Long Island, NY.But at almost the same time, in a shrewd move that greatly strengthened their position in electronic components and consumer electronics in the USA, they bought the Electronic Components and Consumer Electronics divisions of Sylvania from GTE, which included the Sylvania tube plant. This plant continued to make the same tubes, but under the new Philips ECG brandname, which doesn't have anything to do with European Philips Miniwatt, or Amperex tubes.Production was discontinued ca. 1987, but Philips continued (and as far as we know still does) to market tubes under the Philips ECG brand name, by outsourcing tubes from current production manufacturers, when stocks of US made tubes were exhausted.

  My guess is that they are American made and date from the 1980s.  However, it is also possible that they are of Russian or Chinese manufacture (I think that latter is much less likely) and could be from the 1990s.
  

   

  
   

   

  • 9:27 am
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