{"product_id":"woo-audio-wa2-single-ended-otl-headphone-amplifier","title":"Woo Audio WA2 Single-Ended OTL Headphone Amplifier","description":"\u003cdiv style=\"max-width:720px;margin:0 auto;padding:32px 24px 48px 24px;background:#ffffff;\"\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:0 0 0.35em 0;font-weight:600;\"\u003eThe Amp High-Impedance Headphones Were Made For\u003c\/h2\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eIf you own Sennheiser or Beyerdynamic headphones in the 300- to 600-ohm range, the Woo Audio WA2 was built for you. It is a Class-A, single-ended triode amp, all tube. The OTL layout, meaning output transformerless, is prized for one thing above all. It puts the tubes in direct touch with a headphone of high impedance.\u003c\/p\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eIn an OTL design, the output tubes drive your headphones directly. No output transformer sits in the signal path. That means one less component between the music and your ears. Two 6AS7\/6080 power tubes and two 6922\/6DJ8 driver tubes do the work. Dual 6CA4 rectifiers give each channel its own. There are no transistors anywhere in the circuit.\u003c\/p\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eFrequency response runs a wide 8Hz to 100kHz (-3dB). Signal-to-noise ratio is 95dB, and distortion is 0.08% or less. Those are unusual figures for a tube amp at any price.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eHand-Built in New York, Point to Point\u003c\/h2\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eLike every Woo amp, the WA2 is hand-built in New York with point-to-point wiring instead of a circuit board. A 120-watt toroidal transformer feeds the power supply. Each channel gets its own filter choke and rectifier, which is a thorough layout at this price. An ALPS volume control and silver-plated wiring in Teflon round out the build.\u003c\/p\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eThe design is self-biasing. Swapping compatible tubes needs no measurements and no adjustments. The 6922 and 6AS7 families offer decades of production to explore. Four RCA inputs let your DAC, CD player, streamer and phono stage all stay plugged in at once.\u003c\/p\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eThe chassis is anodized aluminum. It measures 13 inches wide, 9 deep and 5.5 tall, and weighs 17 pounds. It takes global voltage from 100 to 220 volts, so it travels without a converter.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eWhat Reviewers Are Saying\u003c\/h2\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eLinden Park of \u003cem\u003eEnjoy the Music\u003c\/em\u003e, in a July 2009 review, wrote that with the WA2 \"the music sounded SET-liquid, silken, and ultimately guileless in expression,\" praised construction that \"is impeccable,\" and called it \"one of the most musically involving amplifiers\" he'd heard and a \"phenomenal value.\" Lieven of \u003cem\u003eHeadfonia\u003c\/em\u003e, in a September 11, 2013 review, described a \"clean top end that maintains extension without being bright, neutral smooth mids and wonderful tight bass,\" naming high-impedance dynamics like the Beyerdynamic T1 and Sennheiser HD 800 among its best matches.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eWho Is This Amplifier Best For?\u003c\/h2\u003e\n\n\u003cul style=\"margin:0 0 0.9em 0;padding-left:1.4em;line-height:1.6;\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eYou own high-impedance headphones\u003c\/strong\u003e — the OTL design is at its best with loads above 100 ohms, like classic Sennheiser and Beyerdynamic models.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eYou want the purest tube signal path\u003c\/strong\u003e — no output transformer, no semiconductors, just tubes driving your headphones directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eYou have multiple sources\u003c\/strong\u003e — four selectable RCA inputs keep your whole system connected.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eYou want to explore tube rolling\u003c\/strong\u003e — self-biasing operation and widely available tube families make experimenting easy.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eYour headphones are low-impedance planars or sensitive IEMs\u003c\/strong\u003e — an OTL amp is the wrong tool for that load, and a transformer-coupled design from our \u003ca href=\"https:\/\/www.audioadvisor.com\/collections\/headphone-amplifiers\" style=\"color:#8a5a2b;\"\u003eheadphone amplifiers\u003c\/a\u003e will serve them far better.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eHow Does It Connect to Your System?\u003c\/h2\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eConnect up to four line-level sources, such as a DAC, CD player, or streamer, to the RCA inputs and select between them from the front panel. Headphones plug into the 1\/4\" jack.\u003c\/p\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eGive the tubes a few minutes to warm up before serious listening, and leave open space above the amp for ventilation, since a Class-A OTL design runs warm by nature.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003ePairs Well With\u003c\/h2\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eBuilding your system? Here are some great companions for the WA2:\u003c\/p\u003e\n\n\u003cul style=\"margin:0 0 0.9em 0;padding-left:1.4em;line-height:1.6;\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeadphones:\u003c\/strong\u003e High-impedance Sennheiser and Beyerdynamic models are classic matches — see our \u003ca href=\"https:\/\/www.audioadvisor.com\/collections\/headphones\" style=\"color:#8a5a2b;\"\u003eHeadphones\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDAC:\u003c\/strong\u003e A quality source makes the most of this amp — see our \u003ca href=\"https:\/\/www.audioadvisor.com\/collections\/digital-to-analog-converters\" style=\"color:#8a5a2b;\"\u003eDigital-to-Analog Converters\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCables:\u003c\/strong\u003e Quality RCA interconnects complete the chain — see our \u003ca href=\"https:\/\/www.audioadvisor.com\/collections\/interconnect-cables\" style=\"color:#8a5a2b;\"\u003eInterconnect Cables\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAudio Rack:\u003c\/strong\u003e Give it a stable, ventilated home — see our \u003ca href=\"https:\/\/www.audioadvisor.com\/collections\/audio-racks\" style=\"color:#8a5a2b;\"\u003eAudio Racks\u003c\/a\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\n\u003ch3 style=\"font-size:1.05em;margin:0.9em 0 0.25em 0;font-weight:600;\"\u003eWhat does OTL mean?\u003c\/h3\u003e\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eOutput transformerless. The tubes drive your headphones directly with no output transformer in the path, a design prized for its immediacy with high-impedance headphones.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:1.05em;margin:0.9em 0 0.25em 0;font-weight:600;\"\u003eWhich headphones work best with it?\u003c\/h3\u003e\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eHigh-impedance models, above 100 ohms, are the ideal match, such as 300-ohm Sennheisers and 600-ohm Beyerdynamics.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:1.05em;margin:0.9em 0 0.25em 0;font-weight:600;\"\u003eWhat tubes does it use?\u003c\/h3\u003e\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eTwo 6AS7\/6080 power tubes, two 6922\/6DJ8 driver tubes, and two 6CA4 rectifiers. The self-biasing design makes tube swaps simple.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:1.05em;margin:0.9em 0 0.25em 0;font-weight:600;\"\u003eHow many sources can I connect?\u003c\/h3\u003e\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eFour, via selectable RCA inputs.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:1.05em;margin:0.9em 0 0.25em 0;font-weight:600;\"\u003eDoes it run hot?\u003c\/h3\u003e\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eLike all Class-A tube amps, it runs warm in normal use. Leave open space above it for ventilation.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:1.05em;margin:0.9em 0 0.25em 0;font-weight:600;\"\u003eWhat's the warranty?\u003c\/h3\u003e\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eWoo Audio covers the WA2 with a 3-year limited warranty.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eSee It in Action\u003c\/h2\u003e\n\n\u003cp style=\"margin:0 0 0.5em 0;line-height:1.55;\"\u003eThe Source AV Design Group shows why the WA2 is a high-impedance headphone's best friend:\u003c\/p\u003e\n\n\u003ciframe width=\"100%\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/nC1JpSg_cbY\" title=\"Woo Audio WA2 OTL Headphone Tube Amplifier Sennheiser High Impedance Headphones best friend!\" style=\"border:0;margin:0 0 0.9em 0;display:block;\" allowfullscreen\u003e\u003c\/iframe\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eWhy Audio Advisor?\u003c\/h2\u003e\n\n\u003cul style=\"margin:0 0 0.9em 0;padding-left:1.4em;line-height:1.6;\"\u003e\n\u003cli\u003e40+ Years of Expertise — Since 1981, we've helped over a million music lovers find the right gear.\u003c\/li\u003e\n\u003cli\u003e60-Day Money-Back Guarantee — Take your time. Listen, enjoy, and make sure it's right for you.\u003c\/li\u003e\n\u003cli\u003eReal Experts, Real Help — Our team is here to answer your questions at 800-942-0220, weekdays 9am–6pm EST.\u003c\/li\u003e\n\u003cli\u003eFree Shipping — On orders over $49, delivered to your door.\u003c\/li\u003e\n\u003cli\u003eFlexible Payment Options — Financing available so you can start listening now.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 style=\"font-size:1.25em;margin:1.4em 0 0.35em 0;font-weight:600;\"\u003eLearn More\u003c\/h2\u003e\n\n\u003cp style=\"margin:0 0 0.9em 0;line-height:1.55;\"\u003eWant to learn more about headphone amplifiers, tube audio, or building a headphone system? Visit our \u003ca href=\"https:\/\/learningcenter.audioadvisor.com\/\" style=\"color:#8a5a2b;\"\u003eLearning Center\u003c\/a\u003e for guides, tips, and expert advice.\u003c\/p\u003e\n\n\u003c\/div\u003e","brand":"Audio Advisor","offers":[{"title":"Black \/ New","offer_id":45983153750189,"sku":"NEW-WAWA2HA-BLK","price":1499.0,"currency_code":"USD","in_stock":true},{"title":"Silver \/ New","offer_id":45982615306413,"sku":"NEW-WAWA2HA-SIL","price":1499.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0750\/3708\/1773\/files\/WAWA2HA_SIL_01_2023__10072.1765918257.1280.1280_4e3e06d6-2f1b-4a95-a930-06e5b97e1b32.jpg?v=1778127098","url":"https:\/\/www.audioadvisor.com\/products\/woo-audio-wa2-single-ended-otl-headphone-amplifier","provider":"Audio Advisor","version":"1.0","type":"link"}