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2359glenn | studio

Discussion in 'Headphone Amps (full-size)' started by silent one, Mar 9, 2012.
  1. whirlwind
    Very nice....good luck with your tube search. Should sound killer with your headphones.
  2. chrisdrop
    Hey all

    In 6080 land - where do GECs rank with any of you users out there? I am considering what premium is worth paying for a matched quad of NOS GEC 6080s. They are not inexpensive, but I am tempted!

  3. L0rdGwyn
    For me, the top probably goes something like:

    1. Bendix
    2. GEC
    3. Mullard

    I think the Bendix are best if you don't have a pair I would give them a try! I tend to prefer other power tubes over 6080s though overall.
  4. mordy
    You may consider mixing one pair of GEC with something different (and less expensive). There are two guys in different corners of the world (Sweden and New Zealand) that seem to have stock - look at this list of what recently sold:
    You may want to contact them and ask if they have additional tubes.

    Personally, I like the GEC 6080 better than the GEC 6AS7 - it is an excellent sounding tube.
  5. chrisdrop
    Thanks for the comments.

    I have just gotten a pair of Bendix and think they sound great. I had been preferring 4x 6080 before and don't fancy my chances at getting 4x NOS Bendix 6080s!

    FWIW - I don't really know what makes 4x better than 2x (or 6x better than 4 in the 6B*7 case), but more does seem better! As a friend of mine often says; "more is more".

    It is funny you mention this. I have the aforementioned 2x Bendix 6080s and was just yesterday wondering about pairing w/ 'other' (less expensive!) 6080s. I will give that a go based on your suggestion.

    Until I purge my mains electrical demon, the 6080s tend to be least noisy overall. I haven't really been able to lean into the various "6 packs" for extended duration. The 6BL7s sound good, but respond poorly to the mains issue and are just noisy. The 6BX7s respond very poorly to the mains issue (I have a dozen or so, including ones that I know worked in another GOTL) and they really amplify the mains cycle. Getting my dedicated mains line in on 10th Dec and various other activities ongoing to defeat the mains demon! I do wish I had a clue why some valves responded more/ less to the mains irritation (on GOTL and FA Euforia too). Enough mains moaning ..

    Since this is all about music; This post brought to you by a German musician; Apparat (whom I am off to see in town this evening w/ Telfon tel Aviv!)

    Ah - and @Velozity - tx for the Anatole ref. Enjoying it today.

    Glad you are enjoying the 6J5s. I have been new to them and really enjoying 100% of them put in the amp. Not possible without @Deyan as you say!
  6. OctavianH
    Maybe the Gain factor?

    Here are some tube amplification factors for power tubes and the ones you mention to be the best seem to have the lowest gain factor:
    6BL7 = 15
    6BX7 = 10
    5998 = 5
    6AS7 / 6H13C / 6080 = 2
  7. chrisdrop
    Quite reasonable thought for outputs. For inputs, I have an 6SL7 in which has a very high gain factor (?70) but is quiet. Perhaps the hum principally gets magnified in the outputs... that may be true. I'd need to consult my crazy experiment list to see what I have done in that space. Tx @OctavianH
  8. mordy
    Was just going to say the same thing - tubes with higher gain amplify the signal more and accentuate noise. This is why 6080/6AS7 tubes may sound better in some situations - less amplification of noise and hum.
    I still do not have the answer to what happens with the multiplication factor when you mix tubes, as an example a pair of 6080 with a pair of 6BL7.
    I have heard that it goes to the lowest number, in other words to 2 in the above scenario, but need confirmation on this.
    (This may be a question for Misha on the 1101 Audio thread.)

    PS: Not sure of this, but it appears to me that driver tubes with high/low gain affect the volume of the amp, whereas the amplification factor of the output tubes has more of an effect on noise and hum. But the latter is speculation - don't know if this is correct because driver tubes can be plenty noisy or hum badly as well.
    Last edited: Dec 4, 2019
    DecentLevi and chrisdrop like this.
  9. OctavianH
    I read here on this thread in the past about this and made a personal note in my own archives, and I think it was @Xcalibur255 who said:
    I hope this clarifies a little bit.
    chrisdrop likes this.
  10. mordy
    Thanks, sounds reasonable. However, using a driver tube that has a gain of 70 together with 6x6BL7 should equal 70x15=1050.
    This is five times more than your example of a 6SN7 and 6BX7 tubes with a gain of 200. I have tried such combinations, and even if it sounds louder, it is nowhere near 5 times louder so it must be a logarithmic scale of some kind.
    And we still need to know how mixing output tubes of different gains affects the mu.
  11. chrisdrop
    Another odd one. That your 2 kinds of different mu outputs make me think of...

    Adding to the c3g slots (with a functioning input and output setup already) I remember making the overall volume went down. That surprised me. I guess this has to do with how the input tubes work together..
  12. Xcalibur255
    I have bought from Jac before and he is good to buy from. He is a part owner of EML, so you are kind of going right to the source when you buy those tubes from him. There is a US reseller called TubesUSA as well. No experience with them.
  13. pippen99
    Sent a price quote request last night. No response yet but not a problem. it's early!
  14. Xcalibur255
    The relationship isn't linear. 1000 won't be 5x louder than 200. The exact mathematical relationship is beyond my current understanding though I'm afraid. I've never run across a really good in-depth discussion on it. There are other parts of the circuit design that affect overall gain too. If you have output transformers some is loss in the stepdown ratio there, and the input stage sensitivity affects it too. The main thing with gain is to really be aware of how much you have in each stage because it can be a source of increased noise.
  15. pippen99
    On the same subject EML, my research noted a lot of love for the 2A3 solid plate over the mesh. Some thought the mesh to be too airy.

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