{"id":1011,"date":"2013-01-05T12:55:04","date_gmt":"2013-01-05T12:55:04","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=1011"},"modified":"2013-01-05T13:08:32","modified_gmt":"2013-01-05T13:08:32","slug":"46-dht-driver-final-tests","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/05\/46-dht-driver-final-tests\/","title":{"rendered":"46 DHT driver final tests"},"content":{"rendered":"<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/20130105-125459.jpg\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1010\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/05\/46-dht-driver-final-tests\/20130105-125459-jpg\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/20130105-125459.jpg?fit=1024%2C607&amp;ssl=1\" data-orig-size=\"1024,607\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.4&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1357383912&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;4.28&quot;,&quot;iso&quot;:&quot;200&quot;,&quot;shutter_speed&quot;:&quot;0.066666666666667&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"20130105-125459.jpg\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/20130105-125459.jpg?fit=840%2C498&amp;ssl=1\" class=\"alignleft size-full wp-image-1010\" alt=\"20130105-125459.jpg\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/20130105-125459.jpg?resize=840%2C498\" width=\"840\" height=\"498\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/20130105-125459.jpg?w=1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/20130105-125459.jpg?resize=300%2C177&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/20130105-125459.jpg?resize=500%2C296&amp;ssl=1 500w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/a><\/p>\n<p>Having built the <a title=\"4P1L Driver Tests\" href=\"http:\/\/www.bartola.co.uk\/valves\/2013\/01\/04\/4p1l-driver-tests\/\">4P1L filament bias driver<\/a> stage in a breadboard, I now have the sufficient voltage swing to drive the <a title=\"4-65a SE Amp: refining the 46 driver\" href=\"http:\/\/www.bartola.co.uk\/valves\/2013\/01\/01\/4-65a-se-amp-refining-the-46-driver\/\">46<\/a> to maximum sweep. In my 4-65a SE amp, a maximum of 200Vpp is required to drive the amp into class A2.<\/p>\n<p>The following tests conditions were used:<\/p>\n<ul>\n<li>4P1L first stage:\n<ul>\n<li>DN2540 gyrator in mu follower output<\/li>\n<li>220nF\/450V Capacitor coupled into 46 driver<\/li>\n<li>Filament bias: 15 ohms, Vgk=-10V<\/li>\n<li>Vsupply=355V and Va0=210V<\/li>\n<li>Output set to about 30-32Vpp to drive 46 at 200Vpp<\/li>\n<\/ul>\n<\/li>\n<li>46 driver stage:\n<ul>\n<li>IXYS 01N100 gyrator in mu follower output<\/li>\n<li>Load impedance is 100K (Pete Millett&#8217;s interface)<\/li>\n<li>Filament bias: 10 ohm \/ 100W Vgk=-17V<\/li>\n<li>Vsupply=355V and Va0=204-208V<\/li>\n<li>Output set to 200Vpp<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>I tested 28 valves. Just a few of my lot are NOS. The average THD was about 0.4-0.5% but a good selection of 8 valves (mainly Sylvania NOS) provided a consistent 0.18% THD:<\/p>\n<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1012\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/05\/46-dht-driver-final-tests\/4p1l-into-46-driver-test2\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png?fit=1414%2C584&amp;ssl=1\" data-orig-size=\"1414,584\" 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 into 46 driver test2\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png?fit=840%2C346&amp;ssl=1\" class=\"alignleft size-full wp-image-1012\" alt=\"4P1L into 46 driver test2\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png?resize=840%2C347\" width=\"840\" height=\"347\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png?w=1414&amp;ssl=1 1414w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png?resize=300%2C123&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png?resize=1024%2C422&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2013\/01\/4P1L-into-46-driver-test2.png?resize=500%2C206&amp;ssl=1 500w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/a>Happy now with the initial tests and selection of 46 pairs for the amplifier, I can now continue with the build&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Having built the 4P1L filament bias driver stage in a breadboard, I now have the sufficient voltage swing to drive the 46 to maximum sweep. In my 4-65a SE amp, a maximum of 200Vpp is required to drive the amp into class A2. The following tests conditions were used: 4P1L first stage: DN2540 gyrator in &hellip; <a href=\"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/05\/46-dht-driver-final-tests\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;46 DHT driver final tests&#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_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":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[150,12,153,67,5],"tags":[780,137,778,280,14,782,6,72,287,44,78],"class_list":["post-1011","post","type-post","status-publish","format-standard","hentry","category-4-65a-se-amplifier-2","category-dht-valves","category-driver","category-thd","category-valves","tag-4-65a","tag-4-65a-se-amplifier","tag-778","tag-46-filament-bias","tag-46-triode-strapped","tag-4p1l","tag-dht","tag-dn2540","tag-filament-bias","tag-gyrator","tag-rod-coleman-regulator"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-gj","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1011","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=1011"}],"version-history":[{"count":2,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1011\/revisions"}],"predecessor-version":[{"id":1014,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1011\/revisions\/1014"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=1011"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=1011"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=1011"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}