Dark Voice 6SN7 Burn In

Burning In 6SN7 Tubes for the Dark Voice 336SE Headphone Amp

11:48 am

If you have a Dark Voice 336SE headphone amp you likely had the same thought as many other owners.  Why does such a nice little amp come with such poor tubes?  Well most Chinese made amps do come with cheap Chinese tubes because they are readily available.  Unlike some Chinese amps that use obscure tubes with limited or no western equivalents to upgrade to, the DV-336SE uses tubes that have many substitution/upgrade options.  It’s most common to upgrade the 6SN7 tube.  We won’t get into which tube sounds best in this article though.  Rather I want to address the common problem folks find when installing their new or NOS 6SN7 tube.  With rare exception, there is a noticeable hum in the left channel.  This will occur with any 6SN7 tube.  But the good news is that after burn-in they will become dead quiet again.  Here’s what to do:

1. Power off the amp and remove the 6AS7/6H13C power tube.  This will  keep the unit from over heating during this burn-in procedure.

2. Install your new 6SN7 tube and power the amp on again.

3.  Wait.  And keep waiting.  We find that by approximately 72 hours will do.

4.  Power off and re-install the 6AS7/6H13C power tube.

5.  Connect your favorite headphones and power the amp on.

You should find the hum in the left channel has completely disappeared.  At the least you’ll notice it’s much quieter and likely only need one more day to get it completely quiet.

I realize you can modify the amplifier and add a couple capacitors to solve this but the instructions above will “fix” it for  free so give it a try.

Note: Image above features the Northern Electric 6SN7.

36 Responses

  1. Richard Kotlar
    Richard Kotlar at |

    Thank you very much for infor
    I have a question if you can please answer for me a Jan Philips 6922 with green writing on the tube is the same quantity or is the same tube with the blue writing a better tube

    Reply
  2. Keith Skronek
    Keith Skronek at |

    This worked perfectly for my Northern Electric 6SN7. Approx 36-40 hrs of burn-in completely eliminated the hum/buzz.

    Reply
  3. miliaanm
    miliaanm at |

    6SL7#6SN7# are very similar pin number
    with 6080#6AS7#6H13C.
    Can you explain of these differencies
    chararacteristic for all users ?

    Reply
  4. Samuel
    Samuel at |

    When you burn in are you leaving the power tube out and only burning in with a driver tube?

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      Thanks for the question. Detailed steps are included in the article above.

      Reply
  5. Alexandre
    Alexandre at |

    Do you leave it 72hrs straight or power it off each X hours for Y hours ?

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      Just turn it on and let it go the full 72 Hours

      Reply
  6. Mitchell
    Mitchell at |

    What headphones do you reccomend for the dark voice 336se?
    I was looking into the 990s 600 ohm and the 880 600 ohm. As well as the HD600/650. which ones do you listen on? i see you have some beyers in the picture which one is that

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      The headphones in the picture are Beyerdynamic DT990 that one of our staff uses. Honestly we are not in the headphone market and preference is very subjective so it isn’t possible to give recommendations. I personally have used AKG, Sennheiser, Master & Dynamic, Beyerdynamic, Audeze, Oppo and Grado (to name a few). We couldn’t say any one was better than the next, just that they are different.

      Reply
  7. Raymond
    Raymond at |

    Is it possible to run the Darkvoice as a pre-amp without the 6AS7 installed?

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      No the preamp section uses both tubes so the 6AS7 must be installed.

      Reply
  8. Marco
    Marco at |

    I’m very new to tube amps, so that’s why i’m struggling to find answers.
    I know that there are official threads about Darkvoice, but they are too technical for me and i ‘ve found many many informations but still not a simple straight one..

    I just got today my Darkvoice 336se with the power big tube broken so I need to buy a replacment but i want to be sure to buy one that will work ,

    Reply
    1. HOWARD
      HOWARD at |

      RCA 6SN7G seems popular.

      Reply
      1. HOWARD
        HOWARD at |

        Apologies that should have read 6AS7G not 6SN7G.

        Reply
    2. Sandra @ thetubestore
      Sandra @ thetubestore at |

      Drop us an email or give us a call 1-877-570-0979 and we can help you out.

      Reply
  9. Jim Spec
    Jim Spec at |

    I just bought a Darkvoice 336 used. It seems in perfect condition but has no manual. could you give me a website for downloading a copy of the manual. Thanks in advance, Jim

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      Sorry but we didn’t get a manual with ours brand new and could not find anything online.

      Reply
    2. chris
      chris at |

      The manual that comes with the Darkvoice is not really a manual but more of a history of how it was designed, and not really worth reading. You can find a translation of it here which includes the specs translated.

      http://www.alternapop.com/2010/06/09/darkvoice-336se-english-manual/

      Reply
  10. CoolCrew23
    CoolCrew23 at |

    I have a Tung Sol 6SN7. Currently on my 90th hour. Still have a hum on the left channel. Should I just keep going or did I get a dud?

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      We have not experienced any issues with the Reissue Tung-Sol 6SN7 in this amp ourselves, but this is assuming you have a reissue and not an original Tung-Sol. If you had hum in both channels and it is now reduced to just the left, it is possible that it is an issue that cannot be rectified by further burn in. We can only guess from this side of the keyboard. You may want to try a different Tung-Sol to be sure. Please contact us directly so we can discuss a warranty replacement if this tube from an order at our store.

      Reply
  11. Andrew
    Andrew at |

    I recently ordered and installed a Northern Electric 6sn7 in my Darkvoice. I immediately had a significant hum. Initially bummed out, I started the burn in process and was quite relieved that by hour 72, it was dead quiet again. The tube is turning out to be fantastic. Very revealing and musical. Just what i was hoping for. Thanks for this article, as I probably would not have gone straight for a 72 hour burn in, and thought the tube was a dud.

    Reply
  12. Linuxmasterx
    Linuxmasterx at |

    In case 72 hrs burning process is not an option (safety reasons, nobody home at times), will a tube with significant hum in both channels (EH Gold, reissue), burn in from 1-2 hrs listening sessions? Tnx

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      If you are following the instructions there will be no issues with heat generated from the equipment as the power tube is not installed and anything generated by the 6SN7 is very minimal at best. Personally we would not consider it a safety concern but advise you do whatever you feel is best in your situation. As for the hours, it is 72 hours total of burn in that is generally required to dissipate the hum. How you get to those 72 hours is completely up to you and how many sessions you are willing to tolerate that hum. We recommend and personally do a 72 hour straight burn in because we can but if you need to do 36 separate 2 hour burn in sessions it will result in the same dissipation.

      Reply
  13. Stéphane
    Stéphane at |

    Hello, I bought one last year, and it came with the manual.

    It’s just a simple booklet all chinese with all the Darkvoice products on it , so for me it’s useless.

    Reply
  14. Errol
    Errol at |

    I purchased a Tung-Sol 6SN7GTB and it has left channel hum. I get no hum from the stock tubes. I have had the Tung-Sol in the DV336SE as specified in the post for about 48 hours.

    I would like to know what to expect in terms of the left channel hum. Should it be gradually dissipating? Or, will it just completely stop after about 72 hours?

    Reply
    1. Sandra @ thetubestore
      Sandra @ thetubestore at |

      It should be gone after the burn in, or at least greatly reduced.

      Reply
      1. Errol
        Errol at |

        The hum is gone. Mad Science.

        Reply
  15. Bill G
    Bill G at |

    I’m glad I found this post! I just bought the Tung-Sol 6SN7GTB and a used GE version too and both hum in my Darkvoice 336se. The new Tung-Sol more so. I’ll try the burn in method but I’m enjoying it too much at the moment even with the stock tubes (they’re not bad, IMO).

    Note to others, I got a NOS 6AS7 (ended up being a Sylvania) and a NOS 6080 (GE). Both work great but I haven’t tried different combos yet. I tried them all to make sure they worked.

    Reply
    1. Bill G
      Bill G at |

      Update. This burn-in technique worked like a charm for the Tung-Sol 6SN7GTB and NOS GE 6SN7 I bought.

      Reply
  16. Patrick
    Patrick at |

    I am guessing the answer to this is an obvious “yes,” but does this extended burn-in time have an impact on the lifespan of the tube? After 72 hours my Tung-Sol still has a pretty noticeable hum on the left side, so I’m letting it go longer. But at this point it has been left on for so long! Isn’t this kind of a lot of hours of simulated “use”? Does this method (no power tube, no sound) have less of an impact on tube lifespan than if there were any sound input/output?

    Also, does swapping the power tube introduce any hum? I take it from your post that it’s a bit less safe to burn in both tubes at the same time since the power tube produces so much more heat. So that leads me to believe that if you are supposed to also burn in the power tube, it could be a bigger problem.

    This is a super helpful post! Thanks for any other help you can provide!

    Reply
    1. Patrick
      Patrick at |

      Update: I’m coming up on 144 hours of burn in and the left side hum has lessened, but is still present. I guess I’ll let it go for a bit longer, but I’m starting to think that no amount of burn in will completely eliminate the hum. That’s a bit disappointing to me. Do I have a bum tube? Or a bum Darkvoice? Or my expectations were too high about eliminating the hum in the first place?

      Reply
      1. Sandra @ thetubestore
        Sandra @ thetubestore at |

        Hi, if after proper thorough burn-in time does not resolve hum, the issue is either not the tube at all, but hum from the amp with any 6SN7 tube installed, or a Tung-Sol 6SN7 tube that coincidentally has an issue of it’s own. However because you notice it is still reducing, I do think it’s only a matter of time before it’s perfect.
        The few days of hours used for burn-in are minuscule in the total lifespan of the tubes.

        Technically speaking, it is the opinion of many folks that the amp’s design is really to blame. Simply installing coupling/bypass caps prevents this hum every time, with any 6SN7. Look into the capacitor mod if you want to avoid this.

        Reply
        1. Patrick
          Patrick at |

          Thanks for the response and the encouragement to not worry too much about the burn in time.

          I’m happy to report that after nearly 192 hours the hum is completely gone from the left side. It was a real marathon, but it worked! Thanks again!

          Reply
  17. Silvestru Hosszu
    Silvestru Hosszu at |

    Hi,

    It took me around 100 hours but my tung-sol tube is silent.
    Do you know if with the SHUGUANG TREASURE CV181-Z the story is the same?

    Reply

Leave a Reply