# \#kit

**URL:** https://forum.headphones.com/tag/kit/70.md

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## [Bottlehead Crack OTL AMP (Kit/DIY) - Official Thread](https://forum.headphones.com/t/bottlehead-crack-otl-amp-kit-diy-official-thread/1937)

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**Author:** [@Torq](https://forum.headphones.com/u/Torq)\
**Replies:** 389\
**Last updated:** [April 22, 2026, 11:10pm UTC](https://forum.headphones.com/t/bottlehead-crack-otl-amp-kit-diy-official-thread/1937 "2026-04-22T23:10:19Z")

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Bottlehead’s basic headphone amplifier kit, the “Crack”, is probably the most well known, and best regarded, kit-based/DIY headphone amplifier there is. It is an all-tube output-transformerless (OTL) design, intended to…

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## [Bottlehead Mainline Non-OTL AMP (Kit/DIY) - Official Thread](https://forum.headphones.com/t/bottlehead-mainline-non-otl-amp-kit-diy-official-thread/5368)

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**Author:** [@lost33](https://forum.headphones.com/u/lost33)\
**Replies:** 3\
**Last updated:** [February 22, 2020, 8:26pm UTC](https://forum.headphones.com/t/bottlehead-mainline-non-otl-amp-kit-diy-official-thread/5368 "2020-02-22T20:26:30Z")

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Even though the Botttlehead Crack is the best known tube headphone amp from Bottlehead, it has its limitatations by design, it was designed for higher impedance headphones 120 + ohms. From Bottlehead’s site: "Two Bot…