Bottlehead Crack

I know a number of people on the forum have these, and they are very highly regarded.
So I thought I’d put together a thread for opinions.

I picked one up during their birthday sale, took 3 or 4 weeks to ship (which they clearly state on the website).

I put mine together yesterday, probably a 4 or 5 hour build. I personally dislike dealing with point to point wiring, and especially with relatively hefty solid core wire but the instructions are exceptional, every length of wire to cut documented including how much to strip. It also includes test processes for the amp at various points. The build involves mains AC voltage and 170+V DC, so you need to be comfortable with that and I’d strongly recommend you get some soldering practice before attempting the build if your new to soldering.

It’s an OTL amp, so you’ll need a headphone that’s got a reasonably high impedance (>150 Ohms).

Initial impression of the amp is extremely positive, mines dead quiet and with HD6XX or my ZMF’s sounds really good. It lacks the speed of some of my other amps, but it’s by no means slow, and it’s just a really nice sound. It might be my favorite amp with the 6XX.

I ordered mine with the Speed Ball mod, but the instructions explicitly state to build the amp without the mod and verify everything works, so mine currently doesn’t have it installed yet, I’ll post additional impressions when I get a chance for some more extensive listening and after I install the speedball mod.


I’m a big fan of the crack for what it can offer, it’s an extremely fun sounding amp, and with the right headphones it can be an awesome combo. Doesn’t work with all headphones, but it doesn’t need do either, pretty sweet stuff :+1:

what are some examples of headphones it does and doesn’t like, M0N?

Works very well with tube classics like the 600 and 650, the high ohm Beyer’s like the t1 and 880 600, works nicely with an adx5000 or r70x, pretty fun with a hd800s, zmf headphones are pretty fun with it, and a few more

I’m thinking about building one soon. I’m not sure if I should go Crack or S.E.X

Hmmm, what headphones are you planning? The S.E.X kit is more for lower impedance dynamics and will perform better with stuff like grados for example

I don’t really have a set plan honestly. I have he DT880 and probably get a pair of Sinn. Just haven’t decided on which, But I have so many other headphones too. I’m wondering if its worth it to try a setup that will work on more headphones overall… or just the high impedance.

Well, if you are looking for something with a wider range of headphones you can use, the s.e.x kit is still pretty nice. Imo it doesn’t preform well with most planars still, but lower impedance dynamic work pretty well

How would the S.E.X work on the Sinn and Beyer? As good as the Crack?

The Crack is designed for headphones of at least “120” ohms.

Anythig less than this will be sub-optimal…so my Focal Clears, MSR7’s, Most Grados, A lot of Planars… just will have blated bass and sound well…“terrible” in comparison to Beyer T90/ T1, Senns HD600, HD800 etc…

One of the “best” parings with this amp are the HD600’s and 800’s…


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The 600s and the crack is an awesome pairing, I really think anyone who has a crack should pick up a 600 lol

They make their TOTL amp called “Mainline”. I built this one and had it for several years, works well with hi and low impedance cans …

From BH:

“Output power is about 600mW. Input impedance is 25Kohms minimum. Gain is around 12dB into 32 ohm headphones at the low impedance output setting. We have used the amp with everything from low impedance Grados to high impedance Sennheisers and even power hungry Audeze phones. They all sound great.”


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I’m just going off of my experiences, I personally don’t prefer any planar I have tried off a mainline or s.e.x. The only bottlehead I liked a planar off of was the neothoriator (I wish they would make more of em lol)

They of course still work fine on a mainline or s.e.x, just imo not the most ideal pairing, would personally rather have a hybrid or quality solid state in the price range

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As of a few weeks back Doc has one for sale!

I would pick it up if I didn’t already have a 845 headphone amp already, I just recall it being sweet when I tried it at a show

Also I’m surprised there is one for sale, I thought they only made 2 of em, just kinda figured they would have been snapped up

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Yeah only 2, but its on the BH site for sale…another website mod is thinking of it as well…I would love to have it, but the retirement budget just wont go there!! LOL!!


Notice the poor Mainline on the right!!!

Doc is a neat guy, a real old school, no nonsense guy thats one of those analog engineers that are a dying breed…like Jim Hagerman etc…the Crack has beed around for so many years like the HD600’s which is in itself a neat diacotomy in that these two old legends work so well together!! Go Figure!!


It’s worthhhh lol. I don’t think I could personally justify owning both the Egoista 845 and the neothoriator lol

Now thats a real interesting name!


It’s an interesting amp for sure lol. I really like my abyss off there. I’ve really been enjoying the 845 tube amps for speakers and wanted one for headphones. I might eventually get an audionote ongaku for my living room setup (real sweet amp, love the 211 designs if they can pull it off right)

Ok I’m going to stop going off topic now lol, anyways back to the glorious bottlehead amps


You need cans with a minimum impedance of 300 ohms. The sound quality is exceptional although I have swapped out the oringal preamp and power tubes.