Bottlehead Crack – “The Review”

Recently I posted a review of the construction stage of my Bottlehead Crack amplifier. The amp’s been in action for a few weeks now and I’m ready to share a review of my impressions.

I’m not going to start with the normal list of specifications for the Crack because it’s so variable due to the massive range of modifications you can make to it. What does matter are the following details:

  • Tube driven amplifier for headphones
  • Designed for high impedance headphones (ideal with Sennheiser and Beyerdynamic cans)
  • Buckets of power


The Bottlehead Crack is a DIY kit sold by Bottlehead in America. It costs around $350 fully shipped to Australia and takes a couple of days to put together if you take your time, but could be completed in a day of assembly, committed soldering and testing.  If you want to know how easy it is to build one of these for yourself, you can check out the build post here: Bottlehead Crack – “The Build”

For $350, this amp is simply incredible. To put it into perspective, the Crack performs on par or better than products like the Woo Audio WA3 (~$580) and Schiit Lyr (~$550). Because of its DIY nature, you can get brilliant performance for a very low price. On top of that, building it yourself means you know what’s going on inside and can easily add to it and improve it either on your own or using the add-n “Speedball” kit from Bottlehead.

To read the full review please head over to the new Passion for Sound site. It’s sexier and there’s lots of great new content.


20 comments on “Bottlehead Crack – “The Review”

  1. Thanks for the write up of the Bottlehead Crack. I was considering it when researching amps for my HD650. But in the end thought I’d start with a Little Dot MkIII. The HD650 certainly pairs well with tube amps. I’ve heard it with a Violectric V100, and found that a bit too clinical compared to the tube amps I tried (LD MkIII, ALO Pan Am, Schiit Valhalla).

    Maybe one day when I build up the courage to build my own amp, I might take this on.

  2. Good review, I am thinking of getting this for my HD650. Did you buy one with Speedball upgrade? Is the 240V transformer separate unit?

    You surely done a nice job with the wooden shell, I like the rustic colour, did you stain it using normal wood stain?

    I am surely interested to get one of this just waiting for another person to join to save additional cost.

    • Thanks for reading!

      I didn’t get the Speedball. There is a really slight background hum that’s really only audible when you’re listening for it and I think adding the Speedball might rectify this – I plan to get it in the future, but was interested in getting the stock kit and getting to know it before upgrading.

      The 240V transformer is a different version of the normal unit they put into the kit – i.e. it’s built into the kit (and looks exactly the same as the 110V one from what I can tell) – it’s the dark grey cube at the back of the amp with the curved metal top.

      Thanks for the compliment on the wood finish. I used Black Japan stain and put it on lightly and irregularly. I also sanded it a little irregularly in between staining and varnishing (and in between coats of varnish). I used a satin varnish.

      Good idea on a group buy. Good luck!!

    • I have heard good things about the Bifrost, but haven’t used it myself.

      I’m really happy with my Audio-gd NFB-5.2 which is a DAC/amp combo (selectable line-out/HP out allows easy switching between the 5.2 solid state amp or the Crack). Audio-gd make dedicated amps too so you could check them out.

  3. Fantastic write up Lachlan….

    The only reason i ended up here was that bottleneck have a offer on this weekend buy it & get the speed ball free and if you ask me that is a real bargain ..& now just needed some more feedback on it and your writeup made my mind up so thanks to you and there offer i have got one but the wife is going to be a little pissed with me mind you.. i was looking at the crack a while back last year & after spending weeks researching valve amps i was going to buy it but due to work never go t round to it until i received an email from bottlehead regarding there offer and guess what i could not say no …who wouldn’t..there going to power my 650’s with high end rme converter 32 bit 192 khz….kind regards sy

      • Not sure yet but i sure did order early so i will have to wait and see….either way i am sure i will be happy as this is my 1st tube set-up coming from solid state …

  4. hi!
    am planning to have this kit also but am here in Riyadh..
    just worried I can’t finish the assembly coz’ of missing parts..
    it’s shipped completely right?..
    meaning everything such as the board, transformer, tubes, wooden box, etc.
    and all you have to do is just solder, etc?..

    • That’s correct Don. They ship everything you need.

      The only issue you could strike is if you accidentally damage a component (like I did) and have to get another one. I imagine Bottlehead would help you out with replacement parts if needed or you can source them locally. This is only an issue if you damage something – otherwise they provide everything you need (except solder and tools).

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  8. Nice write up. Thanks.
    My kit arrived today. (QLD)
    Just a Q on tubes.
    I’m not very knowledgable on tubes
    You state “I found that the combination of the Mullard 6080WA and RCA Cleartop 12AU7 tubes provide the sweetest sound” (aren’t these both the output?)
    But later “The Cleartop RCA 12AU7 I bought makes the sound a bit leaner and brighter, but does so at the expense of ambience and space within the music so it’s all a matter of personal preference.”

    Is it that you accept (prefer) the loss of ambiance and space.

    Thanks for any clarification


    • Hi Simon,

      The 12AU7 is essentially an input tube while the 6080 controls the output.

      The reason I chose less ambience from the RCA Cleartop is because it was nicely balanced by the Mullard 6080WA. 2 Mullards were too much of a good thing and got a bit thick sounding at times, especially with warmer headphones (e.g. HD650s). The Cleartop’s clarity and the Mullard’s warmth and ambience made a perfect pair.

      Thanks for asking to clarify!


  9. Thanks Lachlan.

    I’m away at work. (The kit arrived the day I left…) I can’t wait to get home and begin construction.
    It will be difficult not to rush as I’m so keen to hear it.
    I have HD650s.


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