{"id":1124,"date":"2013-01-26T12:13:51","date_gmt":"2013-01-26T12:13:51","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=1124"},"modified":"2013-01-26T12:13:51","modified_gmt":"2013-01-26T12:13:51","slug":"driving-the-45-in-a2-part-2","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/26\/driving-the-45-in-a2-part-2\/","title":{"rendered":"Driving the 45 in A2 (part 2)"},"content":{"rendered":"<p>On the <a title=\"Driving the 45 DHT in A2\" href=\"http:\/\/www.bartola.co.uk\/valves\/2013\/01\/26\/driving-the-45-dht-in-a2\/\">previous post<\/a> I explored how more power could be extracted from the 45 in class A2. Here is a first draft circuit using the 4P1L as the driver stage with a mu-follower gyrator load to provide current with low output impedance:<\/p>\n<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1125\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/26\/driving-the-45-in-a2-part-2\/45-se-class-a2-dc-coupled\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png?fit=1361%2C955&amp;ssl=1\" data-orig-size=\"1361,955\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"45 SE Class A2 dc-coupled\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png?fit=840%2C589&amp;ssl=1\" class=\"alignleft size-full wp-image-1125\" alt=\"45 SE Class A2 dc-coupled\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png?resize=840%2C589\" width=\"840\" height=\"589\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png?w=1361&amp;ssl=1 1361w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png?resize=300%2C210&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png?resize=1024%2C718&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/45-SE-Class-A2-dc-coupled.png?resize=427%2C300&amp;ssl=1 427w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/a><\/p>\n<p>3.5W can be obtained with 13Vpp input signal. Clearly a pre-amp is required, but that is the output level I&#8217;m currently getting from my preamp so should be fine. The LND150 CCS reference can be optimised and derived from the stable 280V.<\/p>\n<p>Not a bad idea, just an additional power supply to avoid any nasty cap in the path.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>On the previous post I explored how more power could be extracted from the 45 in class A2. Here is a first draft circuit using the 4P1L as the driver stage with a mu-follower gyrator load to provide current with low output impedance: 3.5W can be obtained with 13Vpp input signal. Clearly a pre-amp is &hellip; <a href=\"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/26\/driving-the-45-in-a2-part-2\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Driving the 45 in A2 (part 2)&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[12,158,5],"tags":[124,314,316,48,317,782,319,318],"class_list":["post-1124","post","type-post","status-publish","format-standard","hentry","category-dht-valves","category-se-designs","category-valves","tag-124","tag-45-dht","tag-45-dht-in-class-a2","tag-45-se","tag-45-se-a2","tag-4p1l","tag-4p1l-gyrator","tag-4p1l-gyrator-load"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-i8","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1124","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/comments?post=1124"}],"version-history":[{"count":1,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1124\/revisions"}],"predecessor-version":[{"id":1126,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1124\/revisions\/1126"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=1124"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=1124"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=1124"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}