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6SN7 Tube Addicts

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  1. detoxguy
    Thanks for the info, not super experienced with tubes, have a new Lyr 3 arriving tomorrow and picked up a new production Tung-sol as an upgrade to stock tube they send and saw this NOS Westinghouse but haven’t seen the ‘premium’ label before. Says made in Canada on tube, looking forward to trying it but have no frame of reference hehe
  2. gibosi
    OK. Again, while I am not sure if Westinghouse ever manufactured the 6SN7 in the US, I am aware of the fact that they had manufacturing facilities in Canada. And I am now inclined to believe that yours is not a rebrand. It was very likely "made in Canada" by Westinghouse. Again, I have no experience with this tube, but I do have a VU71 Canadian Westinghouse rectifier and it is quite good.


    After you have spent some time with this tube, how about letting us know what you think?
  3. detoxguy
    Will do, although I currently lack the vocabulary and the experience with other tubes to covey my impressions properly but looking forward to learning.
  4. L0rdGwyn
    Question for the 6SN7/6F8G experts here :) sorry if this is a topic that has been raised, but I haven't found a solution.

    I am running 6F8G drivers on my Bottlehead Crackatwoa OTL using a 6F8G to 12AU7 adapter. They sound fantastic, running Tung Sol VT-99 flat black plate primarily. However, I am getting right channel buzzing with the 6F8G. I suspect the tube is picking up power supply noise and is not properly grounded. If I move a finger close to the top cap, the sound is amplified. If I touch the top plate of the amp, the sound is diminished.

    Has anyone come across this issue? Is this an inherent part of using 6F8G's? I am wondering if there is an effective way to simulate my touching the amp with a ground wire perhaps. It's forced me to use lesser 6SN7's, not quite as good as the VT-99, but without the incessant buzzing. I appreciate your help.
  5. Pharmaboy
    I have a different situation--running 6F8G tubes using Woo's 6SN7 adapter (on WA22). This adapter has a captive silver cord w/a cap that fits over the top of the 6F8G tube seated in it. I'm not a techie, but just assumed one function of this adapter + pigtail (besides pin-matching) is grounding.

    What kind of adapter are you using w/these tubes? Has it worked in other situations?
    Last edited: Mar 5, 2019
  6. gibosi
    Most of us who run 6F8G have encountered the same problem. The 6F8G is quite susceptible to microphonics and extraneous RF noise, and therefore, in the late 1930's, RCA deliberately developed the 6SN7 to be a better 6F8G. So yes, this is an inherent problem when using 6F8Gs. And sometimes it is necessary to roll through several in order to get a quiet one.
  7. L0rdGwyn
    It is Chinese made, so certainly not the pinnacle of quality! I have one other Chinese made 6F8G to 12AU7 adapter that has the same issue. I had considered trying the Woo Audio 6F8G to 6SN7, then stacking with a separate 12AU7 adapter, they look to be of great quality, but I'm just not sure it will fix the problem. This issue is specific to the 6F8G, no problem whatsoever with either 6SN7's or 12AU7's in my amp.

    From what I am hearing, it doesn't sound like your typical microphonic or tube noise, it is a 60Hz buzz, like a ground loop. But if it is inherent to the tubes themselves, I suppose I can learn to live with it, or move on.
  8. gibosi
    Ground hum from transformers, electric motors and so forth is an example of extraneous RF noise.
  9. L0rdGwyn
    Got it, well then I suppose I will roll through my small 6F8G collection and see which have a suitably low buzzing volume. It isn't an issue with moderate-volume music, only with quiet passages or acoustic. Thanks for your input.
  10. leftside
    I’ve thrown out a few 6F8G because they were noisy, but if you find quiet ones they are very good. I have a bunch I could part with. Feel free to PM me if interested.
  11. L0rdGwyn
    Thanks! I will keep that in mind. Would you say some noise is unavoidable even if it is inaudible at listening volumes?
  12. leftside
    With my setups there is no noise whatsoever with no music playing at high listening volumes
  13. Wes S
    I just scored my first STC/Brimar CV1988 black glass, and can't wait to hear the UK sound, from a 6SN7 variant. I only have American made 6SN7 tubes at the moment, so I am looking forward to switching things up. I absolutely love the Brimar CV2492, and use them in my Liquid Platinum. Now, I get to hear the amazingly natural and big sound, in my Lyr 3. Thanks rosgr63!
    Pharmaboy likes this.
  14. leftside
    Those are great tubes! Enjoy.
    Wes S likes this.
  15. L0rdGwyn
    I see...well, I am at a loss. My gut tells me it is a grounding issue, but I lack the expertise to troubleshoot it. C'est la vie.
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