{"id":3902,"date":"2011-11-19T09:08:40","date_gmt":"2011-11-19T14:08:40","guid":{"rendered":"http:\/\/nuxx.net\/blog\/?p=3902"},"modified":"2011-11-19T09:21:47","modified_gmt":"2011-11-19T14:21:47","slug":"amb-%cf%871-complete","status":"publish","type":"post","link":"https:\/\/nuxx.net\/blog\/2011\/11\/19\/amb-%cf%871-complete\/","title":{"rendered":"AMB \u03c71: Complete"},"content":{"rendered":"<p><center><\/p>\n<table cellpadding=1>\n<tr>\n<td bgcolor=\"black\"><a href=\"https:\/\/nuxx.net\/gallery\/v\/stuffivemade\/IMG_6637.jpg.html?g2_imageViewsIndex=2\"><img decoding=\"async\" src=\"https:\/\/nuxx.net\/gallery\/d\/99707-2\/IMG_6637.jpg\" height=427 width=640 border=0 title=\"AMB \u03c71, a LiPo battery retrofit, installed in my AMB Mini\u00b3 headphone amplifier.\"><\/a><\/td>\n<\/tr>\n<\/table>\n<p><\/center><\/p>\n<p>Yesterday evening I finished up retrofitting my <a href=\"https:\/\/nuxx.net\/blog\/2009\/06\/18\/amb-mini%C2%B3\/\">AMB Mini\u00b3 headphone amplifier<\/a> with the <a href=\"http:\/\/www.amb.org\/audio\/chi1\/\">AMB \u03c71<\/a>. This is a battery management board which replaces the original charging circuitry and 9VDC <a href=\"http:\/\/en.wikipedia.org\/wiki\/Nickel%E2%80%93metal_hydride_battery\">NiMH<\/a> battery resulting in a considerably faster charge and longer runtime. By using a <a href=\"http:\/\/en.wikipedia.org\/wiki\/Lithium-ion_polymer_battery\">Lithium-ion polymer (LiPo) battery<\/a> the runtime has been extended to ~25 hours (for my high performance version) while the charging time has been reduced to ~1.5 hours. (AMB.org claims that this is a 10x improvement in charge time and a 3x improvement in run time.)<\/p>\n<p>The photo above shows the rear end of the Mini\u00b3 without the end panel, showing the two LiPo packs (the silver \/ strapping tape pieces) the edge of the \u03c71 PCB (top), and the bi-color charge\/fault indicator LED. Assembling this involved removing a small handful of diodes, regulators, and resistors from the Mini\u00b3&#8217;s PCB, adding a header in place of the LM7812 voltage regulator, and plugging the \u03c71 into that. As <a href=\"http:\/\/www.amb.org\/audio\/chi1\/\">documented on AMB&#8217;s site<\/a> building the \u03c71 was pretty straightforward and involved only a handful of medium-size (and easy to solder) surface mount parts. I almost wish the design was all surface mount so I wouldn&#8217;t have to deal with as much through hole, but I understand his desire to not go all-SMT in order to keep things easy to assemble.<\/p>\n<p>I use this headphone almost every day at work while listening to music from my iPod, and thus far it&#8217;s sounded great. However, due to my weird patterns of not being in the office I haven&#8217;t been leaving it plugged in for long enough lately, so whenever I&#8217;ve been wanting to use it I must plug it in to use it. Hopefully this new version with a shorter charge time and longer run time will sort out that problem.<\/p>\n<p>Now I want to build something else, but I&#8217;m not really sure what. I&#8217;m somewhat considering a beefy Class A amp and new monitor speakers for my desk at home, all nicely integrated with a USB DAC and tucked under my desk. I could even build the monitors themselves, but this would end up being a pretty big project and I&#8217;m not sure it&#8217;d get me enough benefit&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Yesterday evening I finished up retrofitting my AMB Mini\u00b3 headphone amplifier with the AMB \u03c71. This is a battery management board which replaces the original&#8230;<\/p>\n<div class=\"more-link-wrapper\"><a class=\"more-link\" href=\"https:\/\/nuxx.net\/blog\/2011\/11\/19\/amb-%cf%871-complete\/\">Continue reading<span class=\"screen-reader-text\">AMB \u03c71: Complete<\/span><\/a><\/div>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,11,18],"tags":[],"class_list":["post-3902","post","type-post","status-publish","format-standard","hentry","category-electronics","category-making-things","category-work","entry"],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/3902","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/comments?post=3902"}],"version-history":[{"count":6,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/3902\/revisions"}],"predecessor-version":[{"id":3905,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/3902\/revisions\/3905"}],"wp:attachment":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/media?parent=3902"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/categories?post=3902"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/tags?post=3902"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}