Tube Rolling with Bottlehead Crack

Discussion in 'Audio Hardware' started by John Storey, Nov 22, 2017.

  1. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    Just finished the Bottlehead Crack build, which was a ton of fun and it sounds great. I’m looking to start tube rolling now as The Tube Store has a 40% off sale for Black Friday. I’ve looked through their selection, and decided on a 6080 replacement, the Winged "C" 6H13C / 6AS7G and narrowed my choices for the 12AU7 down to three choices.

    Philips ECC82 / 12AU7
    JJ ECC802-S / 12AU7 Gold
    Genalex - Gold Lion ECC82 / B749

    I’m hoping some people have some tube knowledge, of perhaps experience with these tube and the Crack, as I am not very knowledgeable at all when it comes to tubes. I am willing to return some after trying them, but the Philips tube is $90, so I’d like to avoid the 15% restocking fee on that one. Also, I’ll be using the Sennheiser 6XXs (650) and willing be installing a Speedball soon as well. I’m open to other tube suggestions as well! Thanks in advance for the help!
     
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  2. Otlset

    Otlset Forum Resident

    Location:
    death valley
    Walter Koehler and John Storey like this.
  3. Does this kit have the Speedball upgrades?
     
  4. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    Not yet, but it will in a week or two. I want to hear it without it first.
     
  5. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
  6. Here is what I would do,
    Concentrate on the front end mostly and don't worry about the output tube itself. The exception being is the cathode resistors (3k ohm 10w?) for the output tube. You will never lookback if those output tube cathode resistors are replaced with current sources. AND parallel the output coupling capacitors with 10-1uf polypropylene and/or polystyrene capacitors, best you can afford and fit in the chassis (watch voltage ratings).

    THEN dump the rest of your money/efforts on the input section. Replace that input volume pot with a conductive plastic pot or stepped attenuator. The 22k plate resistor must GO! If you get the Speedball kit then that takes care of it. BUT if you don't get the Speedball then get a bulk foil resistor. Don't worry if you can't find 22k ohms exactly, 20k will work just fine.

    Replace the rectifier diodes with Hexfred hfa08tb60.

    AFTER all that, THEN go looking for a nice 12au7 or variant.
     
    Last edited: Nov 22, 2017
  7. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    Wow, that’s a lot to take in! Thanks!
    So if I understand right, I should replace the cathode resisters for the output tube first, then parallel the output capacitors. Next the potentiometer, then replace the rectifier diodes, then the 12AU7 replacement! :yikes: When would I do the 6080 replacemnt? Also, any there any specific recommendations for any of those parts? Looking forward to this! :agree:

    THANKS!
     
  8. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    Anyone have any experience with the Telefunken ECC82? Someone on the Bottlehead forum recommended that one...
     
  9. timind

    timind Bushy

    Location:
    Westfield, IN USA
    I've built a couple Crack's and would recommend installing the Speedball before going wild with tube changes. The Speedball will make a big difference with the sound.

    I never swapped the 6080 tube in my Cracks but will say my favorite 12AU7 was a Sylvania 12AU7WA mil spec tube. Might not have had the tubey sound of some others, but clean, clean, clean sounding.
     
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  10. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    I’m looking into the rectifiers, what is the difference between these two, and which one would I want?

    https://ca.mouser.com/ProductDetail/Vishay/VS-HFA08TB60SPBF/?qs=/ha2pyFaduhCtipGyYETsMVf9UA5sovaC2ph7TJWyAxEs3zDHUpWlw==

    https://ca.mouser.com/ProductDetail/Vishay/VS-HFA08TB60-N3/?qs=/ha2pyFaduhC5usQmGB3Plxd3iY2EAMrvdIU48lf6i%2bSst1aSz7/H4XNdsGjWzca
     
  11. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    I might not use the tubes right away, but it’s a tough deal to turn down.
     
  12. Saycheese78

    Saycheese78 Member

    Location:
    Singapore
    Consider the price, RCA clear top for au7 and rca driver. You will get a totallu different sound although i must admit it is not really to my liking. Too sweet.

    To learn more about tubes, get a mullard au7 and plug the stock driver back. Complete opposite sound to the rca. You will be done with your learning and should be able to decide the sound you desire.

    The audio jack must go. Potential meter for volunw control must be replaced too.
     
  13. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    The RCA jacks or the headphone jack?
     
  14. Jelloalien

    Jelloalien Stylus Genie

    Location:
    Toronto, Ontario
    Is there a link to the 40% off sale? I can’t seem to locate it for some reason and would be curious to check it out. Or is it only in store maybe?
     
  15. timind

    timind Bushy

    Location:
    Westfield, IN USA
    And definitely change the volume pot. I used an Alps Blue Velvet pot on my last Crack and have an Audio Note volume pot for a S.E.X. kit I have in a box. Going to build it after Thanksgiving.
     
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  16. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    It starts on Friday and runs through Monday.
    Here's what I received in the email:


    Set your calendar for weekend savings you won't want to miss!!
    [​IMG]
    [​IMG]
    Prices listed are in US funds. Canadian orders that are shipped to an address within Canada will be converted to CAD after you enter your shipping address.
    All prices on the site will be adjusted to the discounted price from
    Friday November 24th through Monday November 27th 2017.
     
    Jelloalien likes this.
  17. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    I'll be sure to check that one out. I'm thinking I'll place an order for a number of parts to upgrade the Crack besides tubes.
     
  18. Rick58

    Rick58 Forum Resident

    Location:
    Tracy, CA, USA
    I don't know about the others, and yes, it's not a 12AU7 but the Gold Lion 12AX7s I've used sounded excellent, on par or better than used tested good Tele ribbed plates and even some Tesla (Czech) NOS ECC803S clones I got. All these tubes sounded very similar to me, with the Gold Lion winning by a slight margin.
     
  19. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    Anybody have any experience with the RCA 12AU7 clear top?
     
  20. Electronically they will both work the same. The first link is for surface mount applications. Go with the second link, it will be much easier to work with.
     
  21. If you go with the speedball kit I would do that first to see exactly how much room you have left.

    The 6080 itself is the LAST thing I would worry about replacing if ever. From what I have seen you will have to some real coin to get a better version of that output tube
     
  22. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    That’s what I figured, just wanted to check.

    Just because it doesn’t have as big an impact, or?...
    And why am I going to have coin to get a better version?...

    And what exactly is “parallel the output capacitors?” I poses some electronics knowledge, but I’m not sure what I’m thinking is the same as what you mean...
     
  23. EasterEverywhere

    EasterEverywhere Forum Resident

    Location:
    Albuquerque

    A bit more on Pinnacle tubes.
    Pinnacle Vacuum Tubes??

    Pinnacle tubes?? - diyAudio

    I wouldn't fool with them,they sound like a crap shoot.
     
  24. John Storey

    John Storey Well-Known Member Thread Starter

    Location:
    Hamilton, ON
    Hmm, I'm surprised there's so little on them. There is so much about tubes online from audiophiles, it seems odd for a tube to fly under the radar, especially when someone ordered them as an upgrade from Woo... Interesting, thanks.
     
  25. Otlset

    Otlset Forum Resident

    Location:
    death valley
    I notice in both links all those who did offer an opinion on Pinnacle tubes (most were others besides the 13D5A type) were positive. Actually all tube substitutions are a 'crap shoot' when trying to improve the sonic presentation. Some improve it, others don't. My Pinnacle 13D5A improved the sonic presentation in my system the most of all 12au7 types I tried.
     

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