I don't remember who told me about Bottlehead, but I'd like to thank whoever it was that made the introduction. I review and play around with a lot of audio gear, and as much as I love great budget stuff, the best-sounding products are always a lot more expensive. Not this time; the Bottlehead Crack amplifier I'm reporting on today goes for just $219, and it sounds like it's five times that price. Bottlehead has been selling electronic kits for 17 years.
First things first; $219 buys the Crack as a build-it-yourself kit, but Bottlehead's founder Dan Schmalle assures me the kit is super easy to build by anyone who knows which end of a soldering iron gets hot. It should take an evening or two to complete. The Crack is an output transformerless amp, specifically designed for high-impedance (100 ohms or higher) headphones like many Sennheiser, AKG, and Beyerdynamic models (Bottlehead offers other amps tuned for low-impedance Grado, Audio Technica, etc., models).
Most Bottlehead customers buy the kits, but the company sells factory-assembled Crack headphone amps for $369, and considering the Crack's build and sound quality, it's still a major deal. The amp's chassis, real wood base, power transformer, PC boards, and even that nifty little Bottlehead badge are all made in the U.S.A. The Crack is a bit bigger than most desktop amps--it's 7 inches wide and 11.25 inches deep--and it was designed by Paul Birkeland.
I first tried the Crack with my high-impedance Sennheiser HD 580 full-size headphones. I bought these at least 10 years ago, and played 'em with countless receivers and headphone amps, but the Crack took the HD 580's sound to the next level. The sound was pure and clear, but never hard or bright. That's what the best tube amps do, you hear more of what's going on in the music, minus the edge or false hyped "detail" of typical budget-priced headphone amps. The Crack delivers bona fide high-end sound.
Now sure, good quality solid-state amps will produce greater detail and superior bass definition, and if accuracy is what you want, buy a solid-state amp, like Schiit Audio's $249 Asgard amp I raved about last year. But the Crack's added warmth and richness somehow makes everything sound better. Is it adding "coloration" to the sound? Probably, but I like it.
Late in the review I received a pair of Sennheiser HD-650 headphones, which blew away my old HD 580s. The HD 650's bass is tauter, the sound is significantly more transparent and better focused than the HD 580s. Comparing the tube Schiit Audio Valhalla amp and Crack with the HD 650 while listening to the superb "Preservation Hall Hot 4 With Duke Dejan" CD, the Crack sounded more like live music, period. The sound was natural and pure, and the Valhalla was tonally brighter, but that brightness sounded artificial compared with the Crack. To my ears the best tube amps' effortless sound closely mimics the sound of unamplified live acoustic music. The Duke Dejan CD is one of the best sounding New Orleans jazz CDs I own.
With more contemporary music, like Thom Yorke's "Eraser" the HD-650/Crack combination still connected the dots better than the Valhalla. Yorke's textures and bass beats had more meat on their bones, and Yorke's vocals sounded more humanly present. The Crack's bass isn't as tightly defined as the Valhalla's, but there's more body to it.
I recently heard another Bottlehead kit amp at a Head-Fi event in NYC. The amp, the Single Ended eXperimenter's Kit ($469), had a pair of Grado RS-1 headphones plugged into it, and the sound was absolutely gorgeous. I own the same model Grados, but they never sounded like this! Rich, warm, and sweet, with oodles of detail!
I didn't know it at first, but it turns out my Crack has the $99 Speedball upgrade kit, and since I didn't hear the standard version I can't say how that changes the Crack's sound. Bottlehead sells its amps direct worldwide.
Tell us about your experiences with tube headphone amps in the Comments section.