Bottlehead Crack OTL AMP (Kit/DIY) - Official Thread

Got a Bottlehead Crack already built with the Speedball mod and stock tubes (the big one says “GE” on it, not sure what the small one is). Been primarily using it with my HD6XX paired with the Bifrost 2/64 with Apple Music. I tried some tube amps before at CanJam NY, but that’s not the best listening experience for source gear, but it did make me tube curious. Otherwise, my primary amp is the RebelAmp, which is marvelous, and outperformed all the lower end amps I compared it to (Atom Amp, Zen Can, Magni+); I even bought a Piety thinking it would dethrone the Green Monster and save me desk space based on how people fell over each other praising it, only to be disappointed by how harsh I found the treble on it.

The Crack on the other hand been an amazing experience. At first when I plugged the headphones in and started listing, I was completely transported, just getting a 3D experience of euphoric sweetness that carried me away. I made comments here like “I understand how the 6XX could be endgame now” and meant it.

After a few days of listening for many hours a day, I started to notice that after a few hours I started getting this “drowning” feeling, like it was just too much richness swamping me. When I described it to someone else in the community, he compared it to having too many rich desserts in one sitting, and I think that checks out. The sound is still startling, especially when I first start listening, but after a while it becomes too much.

So then I switched back to the Rebel and it was like, “oh yeah, this is still great”. Though the soundstage and positioning are reduced, there’s a sharpness to the notes that the Crack seems to round off. And the “euphonia” effect on the Crack almost seemed like a gimmick in comparison.

The obvious thing to do is to try some new tubes in the Crack, and they’re on their way now–on recommendations from online I ordered two GEC CV4079 with a CV4079 adaptor, and a Clear Top 12AU7A. I’m very curious to see what they do for the sound. But they’re coming from Britain, which for some reason is a haven for tubes, so it might take a while.

It does feel like though there’s some kind of middle ground to be had between the Rebel and the Crack, some that adds a bit of “glow” to the notes and the 3D effect of the Crack while preserving the “cleanliness” of the Rebel and not making me feel like I’m drowning after continuous listening.

An obvious option (besides tube rolling) would be the Schiit Valhalla which is relatively affordable and known for having a much “cleaner” sound. Another option might be the Schiit Lyr+ which, unlike the Crack or the Valhalla, could theoretically replace the Rebel amp entirely, but it’s not a full tube implementation so I’m not sure if it’d be a case of being halfway SS, halfway tube, and great at neither. (I wish I lived closer to the Schittr so I could just try them out.)

From there though, options get much more expensive. The Bottlehead Mainline is supposed to be clean sounding, but I’d have to get it prebuilt (I’ve never used a soldering iron in my life and I’m not starting now) and since it’s $1400 just for the kit and however much more for the build, well, that’s a completely different class of money and I’m not sure I’m willing to pay that much. At that price point there’s some other options as well, the Feliks Echo, the LTA MZ2, the Quicksilver. And from there you start looking at stuff like the DNA Starlett, the Zana Deux, the Dragon Inspire IHA-1 and start thinking “you know maybe I could save up for that”.

And it’s a little crazy. I do have an Atrium coming, so this isn’t just for the 6XX. And I couldn’t believe I paid what I paid for the Atrium. I’m still digesting it, but I fell in love with it at CanJam.

But in terms of amps, I already have the Rebel and every headphone I have sounds wonderful on it already, so what am I doing to myself here? But there’s this sense that headphones like the 6XX and the Atrium are “supposed” to be on tube amps, they’re what sound the best. (I’ve also heard that they sound better on balanced solid state, which has me eying things like the Burson Soloist 3XP and going maaaaybe.) But I’m very ambivalent at this point. If I were sane, I’d stop now and settle for tube rolling the Crack. Maybe I will. At any rate I’ve resolved not to buy anything more for a bit and let things settle instead of rushing from one product to the next. If nothing else it’s been really cool to experience the Crack sound, and get some sense in a proper listening environment of the kind of thing that tubes can do.