{"id":1493,"date":"2013-05-04T20:37:03","date_gmt":"2013-05-04T19:37:03","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=1493"},"modified":"2013-05-04T20:37:03","modified_gmt":"2013-05-04T19:37:03","slug":"push-pull-fascination-part-3","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2013\/05\/04\/push-pull-fascination-part-3\/","title":{"rendered":"Push-Pull fascination (Part 3)"},"content":{"rendered":"

In the quest of refining the 6C4C push-pull design<\/a> I started not long ago, it was suggested by 45 to try a different driver. The famous E180F russian equivalent with gold grid: 6J9P-E<\/a>. \u00a0 \u00a0So I went back at my design and replaced the 4P1L driver with the 6J9P-E. Instead of filament bias, the bias was provided by a pair of red LEDs. The low dynamic impedance of these avoid the use of a \u00a0bypass capacitor. Setting the operating point with the existing supply is a bit tricky but I found that Va=210V \/ Ia=14mA provides good swing and minimum distortion. Biasing the valve at around -3.7V keeps the valve away from grid current which will increase the distortion\u00a0unnecessarily. So here is the circuit:<\/p>\n

<\/p>\n

\"6C4C<\/a>The rest of the circuit remains unchanged. Of course if higher anode current is desired i.e. about 18-20mA, the anode voltage will have to be around 220V. So a different supply arrangement must be sought to achieve this.<\/p>\n

\"6C4C<\/a><\/p>\n

Clearly this amplifier version will provide a strong sweet fingerprint given the higher H2 levels reflected in the simulation. H2 cancellation is not significant and linearity slightly worse than the\u00a0venerated\u00a04P1L brother. \u00a0Interesting to see that the THD increased now to about 0.95% for 8W.<\/p>\n

This driver will provide the character of this amp I suspect. I tried 6e5P with slightly better results (e.g. about 0.8% @ 8W) and will be worth listening to.<\/p>\n

 <\/p>\n

 <\/p>\n

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

In the quest of refining the 6C4C push-pull design I started not long ago, it was suggested by 45 to try a different driver. The famous E180F russian equivalent with gold grid: 6J9P-E. \u00a0 \u00a0So I went back at my design and replaced the 4P1L driver with the 6J9P-E. Instead of filament bias, the bias … Continue reading “Push-Pull fascination (Part 3)”<\/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":[157,5],"tags":[382,383,390,391,386,392],"class_list":["post-1493","post","type-post","status-publish","format-standard","hentry","category-push-pull-designs","category-valves","tag-6c4c-pp","tag-6c4c-push-pull","tag-6j9p-e","tag-6j9p-e-driver","tag-ll1684pp","tag-push-pull-fascination"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-o5","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1493","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=1493"}],"version-history":[{"count":4,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1493\/revisions"}],"predecessor-version":[{"id":1499,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1493\/revisions\/1499"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=1493"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=1493"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=1493"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}