{"id":366,"date":"2012-06-30T15:51:36","date_gmt":"2012-06-30T15:51:36","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=366"},"modified":"2012-06-30T16:05:19","modified_gmt":"2012-06-30T16:05:19","slug":"4%d0%bf1%d0%bb4p1l-thd-sweet-spot","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2012\/06\/30\/4%d0%bf1%d0%bb4p1l-thd-sweet-spot\/","title":{"rendered":"4\u041f1\u041b\/4P1L THD sweet spot"},"content":{"rendered":"<p>Playing around today with the 4P1L chap found a very good operating point where distortion is minimised at maximum anode power disipation:<\/p>\n<ul>\n<li>Va=250V<\/li>\n<li>Vg = -21V<\/li>\n<li>Pa=9W (7.5W anode + 1.5W screen)<\/li>\n<li>Ia=35mA<\/li>\n<li>THD measured at Vo=+22.22dBu (10Vrms)<\/li>\n<\/ul>\n<p>Interesting to see this valve swinging\u00a0beautifully\u00a0at just 0.027% THD&#8230;.<\/p>\n<figure id=\"attachment_367\" aria-describedby=\"caption-attachment-367\" style=\"width: 584px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion.jpg\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"367\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2012\/06\/30\/4%d0%bf1%d0%bb4p1l-thd-sweet-spot\/4p1l-thd-minimum-distortion\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion.jpg?fit=1243%2C772&amp;ssl=1\" data-orig-size=\"1243,772\" 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=\"4P1L THD minimum distortion\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;4P1L THD minimum distortion&lt;\/p&gt;\n\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion.jpg?fit=840%2C521&amp;ssl=1\" class=\"size-large wp-image-367\" title=\"4P1L THD minimum distortion\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion-1024x635.jpg?resize=584%2C362\" alt=\"\" width=\"584\" height=\"362\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion.jpg?resize=1024%2C635&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion.jpg?resize=300%2C186&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion.jpg?resize=483%2C300&amp;ssl=1 483w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/06\/4P1L-THD-minimum-distortion.jpg?w=1243&amp;ssl=1 1243w\" sizes=\"auto, (max-width: 584px) 85vw, 584px\" \/><\/a><figcaption id=\"caption-attachment-367\" class=\"wp-caption-text\">4P1L THD minimum distortion<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Playing around today with the 4P1L chap found a very good operating point where distortion is minimised at maximum anode power disipation: Va=250V Vg = -21V Pa=9W (7.5W anode + 1.5W screen) Ia=35mA THD measured at Vo=+22.22dBu (10Vrms) Interesting to see this valve swinging\u00a0beautifully\u00a0at just 0.027% THD&#8230;.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[12,38,5],"tags":[782,6,784],"class_list":["post-366","post","type-post","status-publish","format-standard","hentry","category-dht-valves","category-valve-tester","category-valves","tag-4p1l","tag-dht","tag-thd"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-5U","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/366","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=366"}],"version-history":[{"count":3,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/366\/revisions"}],"predecessor-version":[{"id":370,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/366\/revisions\/370"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=366"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=366"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=366"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}