{"id":968,"date":"2012-12-31T19:12:11","date_gmt":"2012-12-31T19:12:11","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=968"},"modified":"2012-12-31T20:38:31","modified_gmt":"2012-12-31T20:38:31","slug":"4-65a-se-amp-testing-the-46-driver","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2012\/12\/31\/4-65a-se-amp-testing-the-46-driver\/","title":{"rendered":"4-65a SE Amp: testing the 46 driver"},"content":{"rendered":"<p>46 driver breadboarded. The <a title=\"4-65a SE Amp: 46 Driver Gyrator\" href=\"http:\/\/www.bartola.co.uk\/valves\/2012\/12\/30\/4-65a-se-amp-46-driver-gyrator\/\">mu-follower gyrator<\/a>, the filament bias resistor array and the <a title=\"Teflon sockets (Loctal and UX5)\" href=\"http:\/\/www.bartola.co.uk\/valves\/2012\/12\/03\/teflon-sockets-loctal-and-ux5\/\">nice teflon UX5 socket from Jakeband<\/a>. The filament bias resistor array is formed by 4 10\u03a9 20W dale wirewound resistors. These get very hot so probably need to think an alternative layout or further resistors in parallel:<img data-recalc-dims=\"1\" decoding=\"async\" class=\"alignnone size-full\" alt=\"20121231-191140.jpg\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/20121231-191140.jpg?w=840\" \/>The performance is very good. I just picked up a random 46 from my stock and biased it at 204V (which is the operating point in my design) achieving less than 0.05% at 10Vrms. Need to re-run this test to see how will perform at 70Vrms:<a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-Driver-Test1-10Vrms.png\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" alt=\"46 Driver Test1 10Vrms\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-Driver-Test1-10Vrms-1024x423.png?resize=584%2C241\" width=\"584\" height=\"241\" \/><\/a><\/p>\n<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/20121231-191152.jpg\"><img data-recalc-dims=\"1\" decoding=\"async\" class=\"alignnone size-full\" alt=\"20121231-191152.jpg\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/20121231-191152.jpg?w=840\" \/><\/a><\/p>\n<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/20121231-191204.jpg\"><img data-recalc-dims=\"1\" decoding=\"async\" class=\"alignnone size-full\" alt=\"20121231-191204.jpg\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/20121231-191204.jpg?w=840\" \/><\/a><\/p>\n<div>Using my spice model created from a good 46 valve, THD should be around 0.15% at 200Vpp with a 100K load and performance is great to loads down to 100 ohms. Clearly the load in A2 will change from high impedance to some k\u03a9 so this driver should maintain outstanding linearity all the way through:<\/div>\n<div><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-driver-THD.png\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"974\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2012\/12\/31\/4-65a-se-amp-testing-the-46-driver\/46-driver-thd\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-driver-THD.png?fit=963%2C629&amp;ssl=1\" data-orig-size=\"963,629\" 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=\"46 driver THD\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-driver-THD.png?fit=840%2C549&amp;ssl=1\" class=\"alignleft size-full wp-image-974\" alt=\"46 driver THD\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-driver-THD.png?resize=840%2C549\" width=\"840\" height=\"549\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-driver-THD.png?w=963&amp;ssl=1 963w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-driver-THD.png?resize=300%2C195&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2012\/12\/46-driver-THD.png?resize=459%2C300&amp;ssl=1 459w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/a><\/div>\n","protected":false},"excerpt":{"rendered":"<p>46 driver breadboarded. The mu-follower gyrator, the filament bias resistor array and the nice teflon UX5 socket from Jakeband. The filament bias resistor array is formed by 4 10\u03a9 20W dale wirewound resistors. These get very hot so probably need to think an alternative layout or further resistors in parallel:The performance is very good. I &hellip; <a href=\"https:\/\/www.bartola.co.uk\/valves\/2012\/12\/31\/4-65a-se-amp-testing-the-46-driver\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;4-65a SE Amp: testing the 46 driver&#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":[780,137,778,14,44,78,784],"class_list":["post-968","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-triode-strapped","tag-gyrator","tag-rod-coleman-regulator","tag-thd"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-fC","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/968","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=968"}],"version-history":[{"count":4,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/968\/revisions"}],"predecessor-version":[{"id":1836,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/968\/revisions\/1836"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=968"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=968"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=968"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}