Bottlehead Crack

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by OJneg, Oct 3, 2015.

  1. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Pyrate MZR
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    The Teton at Tyll's Big Sound event did not at all remind me of a Crack. (Granted, can't speak for tubes installed or what sort of stock/modified Crack we're discussing.)

    In other news, fishski is still repairing and tweaking my Crack. Looking at some new caps, maybe adding a choke, and cleaning things up in general. Already came with a Goldpoint stepped attenuator.
     
  2. fishski13

    fishski13 Friend

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    this is the second Crack i've had here at chez fish for repairs. the first one was stock caps + SB + RK27 - i don't remember the tubes. after getting your Crack working again, i think it sounds great/better with the Solen 100uF + GP SA + 5814/6080. we'll see what cleaner signal wire routing, Jantzen caps, and a choke will do.
     
  3. JoelT

    JoelT Friend

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    Glenn OTL - They're custom built at very reasonable prices and have a similar lush/warm, effortless, but dynamic presentation. Mine is noticeably more resolving and layered than my Ragnarok with the HD800, inner detail and plankton are much more apparent (fed by Yggdrasil); though the bass isn't as tight (not surprising). The main issue is availability and wait time if you choose to order one. Demoing them is tough as well, if you don't know anyone who has one.
     
  4. dubiousmike

    dubiousmike Friend

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    Stuffed and soldered my speedball switch mod board (designed by maxhawk) this afternoon. It was smooth sailing right up until the final component, when I discovered mouser sent me a faulty 3 position switch. Doh!

    The switching action seemed off, and thankfully I metered it and discovered no continuity between the pins in any of the positions before soldering it in place. Still, it was really fun to fire up my hakko again after letting my workbench collect dust for nearly a year. Looking forward to finishing the job and hearing 12bh7's and e80cc's at their ideal operating points in the near future - notwithstanding that I have been running them off the stock speedball for nearly five years now.

    [​IMG]

    My choke also landed recently. I just need to pick up some standoffs and figure out how best to mount it along with the two spare 91uf axons that I am planning to wire in parallel, in pace of the third psu cap. The easy answer would be to just ziptie them on top of my existing obbligato film output caps, but I suspect it is probably not the greatest idea to place psu caps right up against output caps. Does anyone know if shielding (foil?) of some sort would eliminate concerns of coupling noise/hum in the output if I were to do this?
     
  5. dubiousmike

    dubiousmike Friend

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    My replacement switch arrived, and my crack is now up and running with the switchmod speedball board and a pristine amperex PQ e80cc (holland) in the A-slot. Hooked her up to my Yggdrasil in place of the mainline for a while this morning - wonderful!

    [​IMG]

    [​IMG]
     
  6. JoshMorr

    JoshMorr Friend

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    Silly question @dubiousmike - what do you think of the upgraded power cord? Noticeable effects?
     
  7. dubiousmike

    dubiousmike Friend

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    Not silly at all! A few comments:
    -The BH power cord is a nice cable and an interesting kit to build - although frankly, a bit physically taxing, due to the extent you are supposed to twist (with a drill) and then braid several fairly rigid pairs of solid core wire.
    -The marine heat shrink is super rigid, and I wish I had cut it in half before applying it in hindsight. There's about 4" of excess heat shrink at each end of my finished cable that means the cable won't bend at all near the two ends.
    -I mostly use the cable with my mainline but would not claim to perceive any obvious sonic differences as compared to the $10 14 awg power cord I was using before hand. Many years ago, a family friend lent me one of his totl bob crump silver reference power cables. Although I can't wrap my head around how or why it would possibly make a difference, I did think, at the time, that I heard some slight improvement in deep bass response using the crump cable with the crack. [Then again, this may well have been the result of confirmation bias in not wanting to report back to the owner that his extended loan of a cable "worth" more than my amp made no difference to me....] I have not done any real a/b'ing with the bottlehead cable, but occasional cable swaps have not given me any immediate impression of sonic improvements. [Then again, again, it is also possible that I now have a confirmation bias against hearing differences with cables (and power cables in particular) because of apparent shilling on that other site and lack of measurements to back up perceived differences.] YMMV of course!
     
  8. CEE TEE

    CEE TEE MOT: NITSCH

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    ^Totally. Glenn and people who like Glenn have been very cool.
     
  9. fierce_freak

    fierce_freak Friend

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    I'm very interested to hear what you think.
     
  10. JK47

    JK47 Guest

    Put together mine this afternoon. Gonna listen to it for a few days before I install the Speed-Ball upgrade. Great instructions, and it fired up right away without issue.

    Gungnir Multibit--> Bottle Head Crack--> HD650... Nice... |\/|
     

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  11. TMoney

    TMoney Shits on SBAF over at Head-Case to be cool

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    Show us the goods, JK! Flip that bad-boy over and post a pic!
     
  12. OJneg

    OJneg The Most Insufferable

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    haha love the tape
     
  13. JK47

    JK47 Guest

    Here ya are... Not the prettiest, but good to go.
     

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  14. TMoney

    TMoney Shits on SBAF over at Head-Case to be cool

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    Nice job!
     
  15. Andre Y

    Andre Y Friend

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    Nice job! My kit is waiting for me to put it together. Did you refinish the transformer bell?
     
  16. JK47

    JK47 Guest

    Thanks \/

    Thats the way the transformer bell came.
     
  17. JK47

    JK47 Guest

    Speedball went in today, works like a charm :punk:
     

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  18. fishski13

    fishski13 Friend

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    Finally got Hands' Crack repaired. The choke really quieted down the PS noise - even using my sensitive Denon D2000 just for testing noise. Both Hands' Crack and the other Crack I repaired suffered the same low level noise. It wasn't terribly obtrusive though. For $12 + shipping it's a no-brainer if you have noise issues. 68uF Jantzen Cross Caps on the outputs. Sounds pretty special driving my AKG 240DF.
     
  19. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I have a 5998 tube waiting at home too. :) Just got it in. I would have sent more tubes for you to try but didn't want to risk it if shipping went bad.
     
  20. fishski13

    fishski13 Friend

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    No worries. I really like what I'm hearing. I think I need to pick up a set of HD6xx soon. Thanks for letting me fix this for you. I've been inspired to finally get off my butt and start DIYing again, including designing my own OTL.
     

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