{"id":5142,"date":"2016-01-03T22:08:02","date_gmt":"2016-01-03T22:08:02","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=5142"},"modified":"2016-01-03T22:08:02","modified_gmt":"2016-01-03T22:08:02","slug":"6z49p-dr6j49p-dr-pentode","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2016\/01\/03\/6z49p-dr6j49p-dr-pentode\/","title":{"rendered":"6Z49P-DR\/6J49P-DR Pentode"},"content":{"rendered":"

A forgotten Russian pentode<\/h1>\n

\"6j49p_dry_goldpins_01_xl\"<\/a>There’s not much information around the 6\u041649\u041f-\u0414\u0420 <\/a>or 6Z49P-DR \/ 6J49P-DR pentode. This pentode was designed for high-frequency operation and durability. It has relatively high transconductance and high mu when is triode connected. Hence, an interesting device for a phono stage given the low capacitances in place as well. \u00a0The 6Z49P is close to his brothers 6Z51P and the famous 6Z52P albeit it has different characteristics.<\/p>\n

I handpicked a sample from my stash which was close to the data sheet specs:<\/p>\n

\"6Z49P-DR<\/a>
6Z49P-DR datasheet – transfer curve<\/figcaption><\/figure>\n

From the data sheet transfer curve above we can \u00a0see that a test point can be chosen easily here:<\/p>\n

    \n
  1. Ua=150V<\/li>\n
  2. Ug2=150V<\/li>\n
  3. Ug3=0V<\/li>\n
  4. Ug1=-1V<\/li>\n
  5. Ia = 22mA<\/li>\n
  6. Is=4mA<\/li>\n
  7. Gm=30mA\/V<\/li>\n<\/ol>\n

    The device under test here measures very close to spec, however it has a lower transconductance, nearly 55% less. If you look at the data sheet, you will notice that the transconductance at this point flats out, so it may explain the difference due to saturation effect:<\/p>\n

    \"6z49p-dr<\/a><\/p>\n

    It is interesting to see that anode resistance is about 60-65k\u03a9 at this point. This info is not available in the data sheet.<\/p>\n

    Now if we trace this valve in triode mode, here is what we get:<\/p>\n

    \"6Z59P-DR\/6J49P-DR<\/a>
    6Z59P-DR\/6J49P-DR triode curves<\/figcaption><\/figure>\n

    The triode curves look very linear at first glance. Also the mu is high (about 50) and the anode resistance is around\u00a03.5k\u03a9. Below is the Spice model fit:<\/p>\n

    \"6z49p-dr<\/a><\/p>\n

    The Spice model can be found here:\u00a06Z49P-DR triode model<\/a>. The capacitances aren’t correct as I couldn’t measure them in triode mode given lack of time. The model is pretty accurate in my view.<\/p>\n

    Now, what about the pentode Spice model?<\/p>\n

    \"Anode <\/a>
    Anode curves for 6Z49P-DR Pentode Screen Voltage = 150V <\/div> <\/div>
    \"Screen <\/a>
    Screen curves for 6Z49P-DR Pentode Screen Voltage = 150V <\/div> <\/div> <\/div>
    \"Anode <\/a>
    Anode curves for 6Z49P-DR Pentode Screen Voltage = 125V <\/div> <\/div> <\/div> <\/div> <\/div>\n

    I had to remove some data sets above due to the saturation effects. However, the model is accurate within the area of normal operation. Here is the pentode Spice model:\u00a06Z49P-DR-PENTODE-VS150V.cir<\/a>.<\/p>\n

    I’m sure this is a nice candidate to play around. Keen to read your experience with this valve if you have listened to it. Please send me your feedback if you can.<\/p>\n

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

    A forgotten Russian pentode There’s not much information around the 6\u041649\u041f-\u0414\u0420 or 6Z49P-DR \/ 6J49P-DR pentode. This pentode was designed for high-frequency operation and durability. It has relatively high transconductance and high mu when is triode connected. Hence, an interesting device for a phono stage given the low capacitances in place as well. \u00a0The 6Z49P … Continue reading “6Z49P-DR\/6J49P-DR Pentode”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_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},"jetpack_post_was_ever_published":false},"categories":[5],"tags":[837,842,838,839,843,338,840,841,844],"class_list":["post-5142","post","type-post","status-publish","format-standard","hentry","category-valves","tag-6j49p","tag-6j49p-triode","tag-6j49p-dr","tag-6z49p","tag-6z49p-triode","tag-6z49p-d","tag-649-","tag-649--triode","tag-russian-pentodes"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-1kW","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/5142","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=5142"}],"version-history":[{"count":5,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/5142\/revisions"}],"predecessor-version":[{"id":5157,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/5142\/revisions\/5157"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=5142"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=5142"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=5142"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}