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Crack;Bottlehead OTL

Discussion in 'Headphone Amps (full-size)' started by ironbut, Mar 9, 2010.
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    Anyone here use UPS to protect the crack?
    I have the crack+speedball upgrade and In my region we have frequent electric problems. I'm gonna use APC br550gi UPS to protect my PC and I wonder if it is safe to power the crack
    with the ups battery, or plug it only to the surge protection.
    this UPS is not using pure sine,
    I heard it can cause problems with the PSU of the computer (active pfc). is this relevant to the crack also?
    I have the latest crack version with the international transformer.

    Also what happens if the crack is not protected with a ups?
    does it damage the crack? and what about the tubes?
    Last edited: Jun 29, 2017
  2. LikeABell
    Better ask this at the BH Forum.
  3. Paladin79
    IMG_2026 (1).JPG IMG_2020 (1).JPG IMG_2023.JPG My present crack build will involve carbon fiber plates with the same setup as my copper plates. One four inch plate on each end along with a ten by six inch top plate. All connections will be to the rear of the amp and there will be dual VU meters and dual single gang Alps pots in the front, headphone jack will be on the right side. The cabinet will be a limed oak so the basic look of the amp will be grey and black with silver showing instead of copper. Later today I hope to have made all necessary cuts and should have the cabinet and plates as they will finally appear. I have some detailed photos of the previous build on the Bottlehead forum gallery page for those who want to see how the cuts were made in all plates.

    There is still a layer of protective plastic in place over the carbon fiber but all cuts are made to cabinet and top plate.
    Last edited: Jul 2, 2017
    Letmebefrank and i luvmusic 2 like this.
  4. Paladin79
    I have to find some proper feet for it, do a lot of sanding and applications of black lacquer but it is coming along. Plates are just set in place right now. I am still a long ways from a piano finish. IMG_2033.JPG IMG_2034.JPG IMG_2035.JPG
    LikeABell likes this.
  5. Timoteo80

    Man you're crazy Tom!....& I like it hahaha
  6. Timoteo80
    I need to re polish the top plate & the aluminum on my Lenco L75 turntable but here is where my system is at as of now....
  7. Timoteo80
    IMG_1765.JPG IMG_1766.JPG
  8. Paladin79
    My son wanted black and I had thought about carbon fiber for a while. Originally he wanted limed oak so we bought about six different finishes but he was not crazy about any of them. He mentioned a black piano finish and then Alanmarkus said the same thing so it is my goal. I am giving this one away so if it does not come out perfectly on looks it will still sound good.

    Wow nicely done matching up to the turntable!! Very pretty.

    My problem is I absolutely hate the idea of reaching across the top of the amp to plug and unplug anything so all of my builds will be this design, transformer and two tubes in top plate, nothing else. I also prefer control over each channel as well as analog vu meters but I am stating the obvious.

    My next build will be a combination of my first two crack builds. It will most likely be limed quarter oak cabinet with copper plates buffed to a high shine. I have a few people wanting the amps so a lot of it has to do with how quickly I can purchase the next few kits. I enjoy building them and I can pretty much wire them in my sleep so it is just a matter of matching up to what some friends want. (I am also being offered a tidy sum for such builds so they have to be perfect.)

  9. Timoteo80

    Well we all dig your posts & seeing the projects come together. Thx for taking the time to share.

    And thx for the compliment. I built that Lenco & glad you noticed them matching. Eventually I am going to rebuild the Crack wood base. I used an epoxy glaze on the Lenco but tried a "triple thick" poly on the Crack. The poly is definitely not as transparent & has a "milky" tone to it which I don't like. It's noticeable side by side. So I'll build my own new base maybe even out of layered plywood/mdf like I did with the turntable & use the better epoxy so they really match nice.

    Good luck on your amp builds Tom!

  10. Paladin79
    IMG_1944.JPG I noticed on the Bottlehead site the other day that you can buy additional bases so that is also a way to go. I do not have a woodworking shop or I would cut some of my own bases. I was able to use a couple different Dremel tools and a jigsaw to cut my two existing bases. It looks like you are using speaker spikes for feet on the turntable. I may use those on the current crack build if I do not find something else more suitable.

    This was an easy build for the most part, carbon fiber has 3M adhesive on the back and it was meant for the interior of a Corvette so it looks decent. I keep an original top plate around so I can make all the proper cuts in any material I use and that is how I line up the cuts on my back plate. I have a couple gold tube guards I want to incorporate on a build one day (front tube only) and they will lend themselves well to a shiny copper steampunk crack. Those require much more work, the black on black crack is ok but easy to give away, my original Crack is a keeper.

    Last edited: Jul 4, 2017
  11. LikeABell
    Hey everyone, a seller is willing to sell a pair of Tronix 6AS7G tubes. They're made in USA. Does anyone have any info on these tubes?
  12. bookemJ
    Hey guys got a question from a noob, I bought an Amperex 7308 tube and dropped it in my Bottlehead Crack w/ Speedball and it didn't light up/make any noise. Went to test it at a shop and it worked after cleaning the pins a bit. Brought it back home tried it again and it didn't work in my BHC again. So I sent it back got a replacement thinking it was the tubes/socket not touching correctly and just got the replacement and this 1 doesn't work in my BHC either.

    Any tips you guys got I can try before I give up on this tube?
  13. ProfFalkin
    Is the 7308 compatible?


    Doesn't look like it based on that list.
  14. Timoteo80
    Have you checked other tunes to make sure it is not a bad connection in your Crack?
  15. Timoteo80
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