November 5, 2012

• Valvo 6922

  The review set of Valvo 6922 dual triodes is a mixed bag:  three of them were manufactured in Germany, one by Amperex in Hamburg and the other two by Siemens in Munich; the remaining four were produced in the Amperex Heerlen, Holland plant.  The vintages also vary:  three were made in 1964, one in 1969 and the remaining three in 1970.

  In addition, five of the tubes bear a red Valvo label while the remaining pair (both 1970 Heerlen-made) is white label.  The red label group was most likely destined for industrial use while the much more common white pair for consumer consumption.

  Valvo 6922 at Work in Premier 16LS2                                                      Valvo 6922 (Amperex, Hamburg)
        

  
  Valvo 6922 (Amperex, Heerlen)                                                              Valvo 6922 (Amperex, Heerlen)                                                

       

  Valvo 6922 (Heerlen) Close-Up                                                               Valvo 6922 Getter Support (Amperex and Siemens)
       

  Valvo 6922 Heerlen 1964 Date Code
  

  
  The Valvo 6922’s replaced a set of seven Amperex 6922 PQ (USA) tubes with the large O-ring getter.  During the course of break-in, their sound did change at around the 10 hour mark.  They were initially somewhat bass-shy and the midrange had a hollow quality.  Both of these characteristics disappeared as the New Old Stock (NOS) tubes burned-in.

   

  Listening Impressions:

  • Transients are sharper with a more clearly delineated timbre when listening to the 20-bit mastered American Acoustic CD (disc 1).  Strummed acoustic guitar is precise and delicate while fingers sliding across guitar strings are clearly heard.
  • Decay is long even though the music is quick and sprightly. 
  • Detail is first-rate on the Teldec recording of Vivaldi’s The Four Seasons with Nikolaus Harnoncourt conducting the Concentus musicus Wien.  When this disc is played via the Oppo BDP-95, the cabling is purely XLO Signature straight through to the speakers (1.1 IC => 1.1 IC => 5.1 SC) and there is a purity of tone and clarity of detail that’s like an open doorway to the music’s venue.  The greater richness of tone is clearly evident on this transcription using contemporary instrumentation when compared to the equally excellent, period-instrument rendition on Archiv by Trevor Pinnock leading The English Concert.     
  • The oboe solo on “Prairie Lullaby” from disc 2 of American Acoustic is sad and plaintive.  The contribution of the Amperex-made tubes clearly in play.
  • Certain sound effects, such as the rustling of curtains, on the blu-ray presentation of HBO’s  Rome series are extremely realistic.
  • Although the sound stage is almost as good as it gets on my system, images are more diffuse and not quite as dense as with the all-Amperex 6922 PQ tube complement.
  • Likewise, percussion is near reference level but not quite in the same league as the all-Amperex 6922 PQ presentation.

   

  The Valvo 6922 is another first-tier dual triode in this tube family.  This particular combination definitely has the Amperex house sound but it’s leavened with some Teutonic coolness thanks to the Siemens-made Valvo’s that are in the mix. 

  I would venture to guess that a set of Valvo 6922’s comprised solely of tubes made by either Amperex or Siemens might possess a character indistinguishable from those branded with their manufacturer’s own name.  But then, my experience with the Telefunken made PCC88’s and the PCC88’s made by Siemens might belie my previous comment. 

  You never really know until you try them for yourself. 

   

  • 5:16 am
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