{"id":436,"date":"2012-07-14T18:20:31","date_gmt":"2012-07-14T18:20:31","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=436"},"modified":"2012-07-14T18:20:31","modified_gmt":"2012-07-14T18:20:31","slug":"4-65a-se-driver","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2012\/07\/14\/4-65a-se-driver\/","title":{"rendered":"4-65a SE driver"},"content":{"rendered":"

46 DHT in triode mode as a driver<\/h1>\n
\"\"<\/a>
46 driver THD analysis<\/figcaption><\/figure>\n

Continuing with the design of the 4-65A SE amplifier based on M. Koster design<\/a>, I’m in the process of tweaking the 46 driver to optimise the operating point and provide maximum distortion to drive the demanding 4-65a. Here<\/a> is the circuit I’m currently working on.<\/p>\n

The current 46 driver will be biased at around 25-30mA using filament bias, so Vgk will be around -16 to -17.5V using a 10\u03a9 filament bias resistor array. This will set the 46 at around 185-210V which will give sufficient headroom (i.e. need about 200Vpp max) to drive the 4-65a.<\/p>\n

So today I look at varying slightly both anode currents and Vgk to see impact on THD.<\/p>\n

So minimum THD is around -17V and Ia=30mA. So if setting the Rod Coleman filament regulator to ensure that Vgk=-17V and the anode gyrator to set anode voltage to ensure Ia is close to bias current would provide the minimum distortion (which is 0.04% in this example). Pa is close to 7W, but looking at the datasheet we can see that maximum Pa is 10W (as the latter 45 version).<\/p>\n

\"\"<\/a>
46 Super Silvertone THD<\/figcaption><\/figure>\n

 <\/p>\n

So next I need to build a prototype of this driver with filament regulator and gyrator load.<\/p>\n","protected":false},"excerpt":{"rendered":"

46 DHT in triode mode as a driver Continuing with the design of the 4-65A SE amplifier based on M. Koster design, I’m in the process of tweaking the 46 driver to optimise the operating point and provide maximum distortion to drive the demanding 4-65a. Here is the circuit I’m currently working on. The current … Continue reading “4-65a SE driver”<\/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":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[12,67,5],"tags":[780,778,14,6,44,78,784,39,7],"class_list":["post-436","post","type-post","status-publish","format-standard","hentry","category-dht-valves","category-thd","category-valves","tag-4-65a","tag-778","tag-46-triode-strapped","tag-dht","tag-gyrator","tag-rod-coleman-regulator","tag-thd","tag-valve-tester-2","tag-valves-2"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-72","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/436","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=436"}],"version-history":[{"count":1,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/436\/revisions"}],"predecessor-version":[{"id":439,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/436\/revisions\/439"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=436"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=436"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=436"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}