{"id":3557,"date":"2014-07-02T19:50:16","date_gmt":"2014-07-02T18:50:16","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=3557"},"modified":"2014-07-02T19:50:16","modified_gmt":"2014-07-02T18:50:16","slug":"robustiano-4p1l-se-schade-feedback-tests-part-i-and-ii","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2014\/07\/02\/robustiano-4p1l-se-schade-feedback-tests-part-i-and-ii\/","title":{"rendered":"Robustiano: 4P1L SE Schade Feedback tests Part I and II"},"content":{"rendered":"

Here are some further tests using automated measurements. Firstly I tried same configuration running the 4P1L at closely 38mA and 160V screen voltage. Second test, I dialled up the screen voltage to 171V and tweaked feedback to get current up to 40mA<\/p>\n

Interesting to see that the performance is more triode-like and has a higher THD at lower output levels, however at higher levels the THD is lower. Mainly dominated by H3 and significant rise of H5 given grid current I suspect:<\/p>\n

\"Robustiano<\/a>Here is the harmonic distribution of the first test (more pentode like)<\/p>\n

\"Robustiano<\/a><\/p>\n

Here is the harmonic distribution of the second test (more triode like):<\/p>\n

\"Robustiano<\/a>From a frequency response perspective, it performs very good with -3dB from 10Hz to up to 35kHz at 1W tested level:<\/p>\n

\"Robustiano<\/a>What surprised me was to find out the increasing distortion at HF. Will this be due to the 4P1L grid capacitance or the DN2540?<\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Here are some further tests using automated measurements. Firstly I tried same configuration running the 4P1L at closely 38mA and 160V screen voltage. Second test, I dialled up the screen voltage to 171V and tweaked feedback to get current up to 40mA Interesting to see that the performance is more triode-like and has a higher … Continue reading “Robustiano: 4P1L SE Schade Feedback tests Part I and II”<\/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":[5],"tags":[782,617,322,616],"class_list":["post-3557","post","type-post","status-publish","format-standard","hentry","category-valves","tag-4p1l","tag-4p1l-schade-feedback","tag-4p1l-se","tag-robustiano"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-Vn","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/3557","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=3557"}],"version-history":[{"count":1,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/3557\/revisions"}],"predecessor-version":[{"id":3562,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/3557\/revisions\/3562"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=3557"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=3557"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=3557"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}