{"id":1374,"date":"2013-03-24T12:57:57","date_gmt":"2013-03-24T12:57:57","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=1374"},"modified":"2013-03-27T20:11:47","modified_gmt":"2013-03-27T20:11:47","slug":"2e24-dht","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2013\/03\/24\/2e24-dht\/","title":{"rendered":"2e24 DHT"},"content":{"rendered":"

\"IMG_0369<\/a>\u00a0It was suggested to me recently by Piotr to explore the 2e24<\/a> after looking at the 2e22. This small directly heated pentode have about 10-12W of anode dissipation depending how it’s wired. I suspected this DHT in triode mode will have a high anode resistance so as soon as I managed to get hold of a sample, I submitted it to the mercy of my curve tracer:<\/p>\n

<\/p>\n

\"2e24<\/a>
\n<\/a><\/p>\n

Ra is on the range of directly heated pentodes wired in triode of similar size. Here is the triode model matching these curves:
\n\"2e24<\/a>Now let’s see how this little fellow will perform with a Zaa=6k5 load:
\n\"2e24<\/a><\/p>\n

Not that great, probably will be better in Schade feedback:<\/p>\n

\"2e24<\/a><\/p>\n

\"2e24<\/a>Applying only 10% of feedback reduces the Ra to about 1k3 and the triode SPICE model still matches quite well the curves. So how will perform then with the same load?<\/p>\n

\"2e24<\/a>We can see an improvement by applying Schade-like feedback. We can squeeze out about 1.5W @1.1% THD but paying the price of a higher H3 component in the mix. Interesting to see that the driving requirements are low (about 54Vpp).<\/p>\n

A valve that could be driven by a simple MOSFET common-source stage and will make a very small and simple amplifying stage…<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0It was suggested to me recently by Piotr to explore the 2e24 after looking at the 2e22. This small directly heated pentode have about 10-12W of anode dissipation depending how it’s wired. I suspected this DHT in triode mode will have a high anode resistance so as soon as I managed to get hold of … Continue reading “2e24 DHT”<\/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":[12,24,38],"tags":[365,367,369,366,368,352],"class_list":["post-1374","post","type-post","status-publish","format-standard","hentry","category-dht-valves","category-valve-curve-tracer","category-valve-tester","tag-365","tag-2e24-curves","tag-2e24-schade","tag-2e24-triode","tag-2e24-tube","tag-schade-feedback"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-ma","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1374","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=1374"}],"version-history":[{"count":4,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1374\/revisions"}],"predecessor-version":[{"id":1384,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1374\/revisions\/1384"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=1374"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=1374"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=1374"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}