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Woo Audio WA7TP (tube power supply) Impressions Thread

Discussion in 'Headphone Amps (full-size)' started by warrenpchi, Apr 20, 2014.
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  1. HiFiGuy528
    I am surprised. HD800 with WA7+WA7tp is a great pairing. That is my personal system as well. I mostly use the internal DAC. Are you using TIDAL HiFi and are your FLAC files at least CD quality (16/44.1)?
  2. Dogmatrix
    6350 is not a drop in replacement adapters are required
    Rolled in a pair of Sylvania 6350 nos 1957 about three days ago
    Best tube I have ever had in my Wa7tp , easily the most dynamic spacious and detailed presentation yet
    Downside  ; adapters are required as the grid and plate connections are reversed and the adapters block the led's so you only get the much more subdued light from the heaters .
  3. groovyd

    pictures or it didn't happen
    kyle1010 likes this.
  4. Dogmatrix
    So did happen
    P9120010.jpg P9120032.jpg
    Shot 1 next to a standard "long plate" 12au7 , plates in the 6350 are 20mm
    Shot 2 close up of very cool old school Sylvania logo peeping out
    Shot 3 wide shot
    Will take a couple of shots with tubes lit this evening oz time
  5. Dogmatrix
    6350 lit vs 6c45 with led
    P9120003_1.jpg P9120012_1.jpg
  6. Jeb Listens
    This is so cool... sure it changes the look of the WA7tp a little bit... but if it sounds great, what the hell!  It's quite nice the way the tubes poke their little heads above the glass like that.  If only there was a longer tube that would work in the WA7 too! 
    Would be great to hear what similarities/differences you can draw vs some of the usual suspects like the Mullards, Sylvania JANS, clear tops etc.  Or does it just surpass them all in all departments?
    By the way, you take a beautiful photo, sir.  The clean modern look of the WA7 works beautifully against the weathered wood and a great choice of colour for the backdrop.  It makes me think of swimming pools and beachfront cocktails. 
  7. Dogmatrix
    Just looked up the code on these Sylvania 6350 tubes (57-20  274) , turns out they are probably 1957 but RCA not Sylvania
    Sylvania are said to be the best of the 6350 and these sound amazing so I will have to try and hunt down some genuine Sylvanias , see if they are better than these pretenders
  8. Dogmatrix

    Thanks JL
    They are very much like the Hytron 5814a which I find an improvement on the Sylvania Jan 5814a but with even more punch and control , very tight bass and heaps of detail in the mids and highs
    For me the real winner is the sense of space , makes my HE500 sound like my HD800
  9. Jeb Listens
    Far out - very tempting indeed. And people said this wasn't a tube-roller's amp! Are you using the eBay 12AU7/6350 adapters from China/Hong-Kong ?
  10. groovyd
    Sign me up for a couple pair of these and the adapters from the true sylvania if you find them please pm me where to get this stuff.  I love the logo on the tubes especially the Made In USA tagline!  Where do I get me a pair?
  11. groovyd
    ordered 4 adapters off ebay and 4 tubes off TubeZone in UK... would love to get a set of the same ones you got though, just love the logo.
  12. groovyd
    just curious what makes the 6350 and 12au7 different from a curves perspective?  do they handle more power or more linear or something?
  13. Dogmatrix

    They were built for early computers as far as I can find for power switching rapid on off cycles
    One article said they were particularly suited to phase inversion so I figured they would probably serve well as rectifiers
    Only had a quick look at the data sheets power handling is up
    I bought these on Ebay about three months back meaning to build adapters myself , never got round to it
    Recently I was searching for parts to build said adapters and found these from China so jumped on in
    Have not seen these particular 6350 since , they came from a bulk case in Italy
  14. abvolt
    That is cool even though I don't own my wa7/tp any longer I'd sure like to know what you guys think your impressions please..
  15. Dogmatrix
    So taking a closer look at the data sheets there are some major deviations
    Plate resistance the 6350 is a little less than 50% of 12au7 3900 Ohms for 6350 and 7700 Ohms for 12au7
    Transconductance is around double at 4600 umhos for 6350 and 2200 umhos for 12au7
    Plate characteristics graph shows double current to volts rate 15ma at 60v for 6350 vs 15ma at 120v for 12au7
    Interelectrode capacitances are also around double grid to plate 3.2 uuf for 6350 and 1.5 uuf for 12au7
    Amp factor is comparable at 18 for 6350 and 19 for 12au7 
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