{"id":1061,"date":"2013-01-13T10:13:17","date_gmt":"2013-01-13T10:13:17","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=1061"},"modified":"2013-01-13T18:20:15","modified_gmt":"2013-01-13T18:20:15","slug":"a-c3g-driver","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2013\/01\/13\/a-c3g-driver\/","title":{"rendered":"a C3g driver…"},"content":{"rendered":"

Sunday morning and my brain already started with a lot of activity early today. Should be the other way round. I spent all week working and weekends should be about relaxation, but can’t help it \ud83d\ude42 Before going up to the workshop and continue with the 4-65a SE amplifier build<\/a>, I put into work some of these ideas that are flying around.<\/p>\n

The 46 filament bias driver<\/a> with its hefty supply will be “the driver” for the 4-65a, yes, no doubt. I may want to try some other combinations such as 4P1L pentode in filament bias<\/a>, or why not some other drivers as 6e5p<\/a>, C3g and D3a<\/a>. All these are brilliant candidates. But final judge should be my ears. We all know that what looks really good in paper not necessarily translates into a great sounding driver, but at least is the best start.<\/p>\n

\"C3g<\/a>C3g (as well as D3a) a really linear and revered valves in triode mode. Huge gain, current capability and transconductance. Perfectly engineered valves. C3g can easily provide a great performance as a driver with a gyrator load. I found playing around that with a simple LED bias, a bias of -2V, 190V and 30mA provides an outstanding 0.15% @ 200Vpp at least on the simulations..<\/p>\n

I may try this in my 4P1L\/6C4C <\/a>project as well…. (so much to do)<\/p>\n

Ale<\/p>\n

Edit<\/h1>\n

 <\/p>\n\n\n\n
Hi Ale,
\nA few observations.
\n190V with 31mA provide dissipation of 5.9 W !! It is excessive.
\nUse Telefunken data. Pa max is 3,5W.
\nAlso, look data : \u201cG2 and G3 connected to A<\/p>\n

Just as a long-time user C3g as driver\u00a0\":-)\"<\/p>\n

Rajko<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/blockquote>\n

You’re right, interesting oversight which reflects that I shouldn’t be doing this early on a Sunday morning! Looking at the datasheet, we could get out 4.9W maximum if using Pa=3.5W + Pg2=0.7W + Pg3=0.7W. Well, a bit too much, perhaps safer running it below 4.5W.<\/p>\n

So let’s see how it performs if we dial down the anode current. I ended up changing the LED to minimise distortion:
\n\"C3g<\/a><\/p>\n

The THD is 0.26%@ 200Vpp which is similar to my two stage 4P1L-46. I wonder how much distortion the 4P1L will give at 200Vpp?<\/p>\n

 <\/p>\n

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

Sunday morning and my brain already started with a lot of activity early today. Should be the other way round. I spent all week working and weekends should be about relaxation, but can’t help it \ud83d\ude42 Before going up to the workshop and continue with the 4-65a SE amplifier build, I put into work some … Continue reading “a C3g 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":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[158,67,5],"tags":[272,280,301,295,300,299],"class_list":["post-1061","post","type-post","status-publish","format-standard","hentry","category-se-designs","category-thd","category-valves","tag-46-driver","tag-46-filament-bias","tag-4p1l-pentode-driver","tag-c3g","tag-c3g-driver","tag-c3g-triode"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-h7","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1061","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=1061"}],"version-history":[{"count":3,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1061\/revisions"}],"predecessor-version":[{"id":1069,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/1061\/revisions\/1069"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=1061"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=1061"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=1061"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}