{"id":8226,"date":"2020-02-08T17:00:36","date_gmt":"2020-02-08T17:00:36","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=8226"},"modified":"2020-02-08T17:00:36","modified_gmt":"2020-02-08T17:00:36","slug":"ux-120-dht","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2020\/02\/08\/ux-120-dht\/","title":{"rendered":"UX-120 DHT"},"content":{"rendered":"<p>I&#8217;ve got hold of a NOS quartet of UX-120 Radiotron valves made in 1925. These are 95 year old beauties. Unbelievable how well conserved they are and operate.<\/p>\n<p>This valve developed by RCA was the first output valve intended to be used with dry-cells (3 No. 6 cells in series). See the data sheet extract below:<\/p>\n<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-datasheet.jpg\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"8227\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2020\/02\/08\/ux-120-dht\/ux-120-datasheet\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-datasheet.jpg?fit=679%2C1010&amp;ssl=1\" data-orig-size=\"679,1010\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"UX-120 datasheet\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-datasheet.jpg?fit=679%2C1010&amp;ssl=1\" class=\"size-full wp-image-8227 aligncenter\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-datasheet.jpg?resize=679%2C1010\" alt=\"\" width=\"679\" height=\"1010\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-datasheet.jpg?w=679&amp;ssl=1 679w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-datasheet.jpg?resize=202%2C300&amp;ssl=1 202w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 984px) 61vw, (max-width: 1362px) 45vw, 600px\" \/><\/a><\/p>\n<p>There is no much data available on this valve, if you have some please share and let me know. Here are the curves I traced from a sample which measured 114%:<\/p>\n<p><!--more--><\/p>\n<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png\"><br \/>\n<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"8228\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2020\/02\/08\/ux-120-dht\/ux120-triode\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?fit=5760%2C5040&amp;ssl=1\" data-orig-size=\"5760,5040\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"UX120 triode\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?fit=840%2C735&amp;ssl=1\" class=\"size-large wp-image-8228 alignnone\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode-1024x896.png?resize=840%2C735\" alt=\"\" width=\"840\" height=\"735\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?resize=1024%2C896&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?resize=300%2C263&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?resize=768%2C672&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?resize=1536%2C1344&amp;ssl=1 1536w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?resize=2048%2C1792&amp;ssl=1 2048w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?resize=1200%2C1050&amp;ssl=1 1200w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?w=1680&amp;ssl=1 1680w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-triode.png?w=2520&amp;ssl=1 2520w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/a><\/p>\n<p>I developed a Spice model as well for the ones interested in this valve:<\/p>\n<p><a href=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"8229\" data-permalink=\"https:\/\/www.bartola.co.uk\/valves\/2020\/02\/08\/ux-120-dht\/ux-120-triode-spice-model\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?fit=1719%2C1258&amp;ssl=1\" data-orig-size=\"1719,1258\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"UX-120 triode Spice Model\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?fit=840%2C614&amp;ssl=1\" class=\"size-large wp-image-8229 aligncenter\" src=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model-1024x749.png?resize=840%2C614\" alt=\"\" width=\"840\" height=\"614\" srcset=\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?resize=1024%2C749&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?resize=300%2C220&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?resize=768%2C562&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?resize=1536%2C1124&amp;ssl=1 1536w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?resize=1200%2C878&amp;ssl=1 1200w, https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX-120-triode-Spice-Model.png?w=1719&amp;ssl=1 1719w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/a>You can download the model here: <a href=\"http:\/\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2020\/02\/UX120-DHT-model.txt\">UX120-DHT-model<\/a><\/p>\n<p>It should be an interesting candidate for a line stage with its low Mu. With a hybrid mu-follower using the gyrator PCB should work nicely. Could be biased around -6V\/6mA which should give a very low anode voltage (aproximately below 70V). This could be implemented with a SiC filament bias array of 6 diodes. The tungsten filament requires only 125mA. Big question here is how microphonic the valve is? Only way is to test it. I will add it on the list \ud83d\ude42<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I&#8217;ve got hold of a NOS quartet of UX-120 Radiotron valves made in 1925. These are 95 year old beauties. Unbelievable how well conserved they are and operate. This valve developed by RCA was the first output valve intended to be used with dry-cells (3 No. 6 cells in series). See the data sheet extract &hellip; <a href=\"https:\/\/www.bartola.co.uk\/valves\/2020\/02\/08\/ux-120-dht\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;UX-120 DHT&#8221;<\/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":[12,156,24],"tags":[1292,373,1294,1295,1291,1293,1296,1297],"class_list":["post-8226","post","type-post","status-publish","format-standard","hentry","category-dht-valves","category-pre-amplifier-valves","category-valve-curve-tracer","tag-120-tube","tag-dht-spice-model","tag-rca","tag-rca-radiotron-1925","tag-ux-120","tag-ux-120-tube","tag-ux-120-tube-spice-model","tag-ux-120-valve"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-28G","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/8226","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=8226"}],"version-history":[{"count":1,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/8226\/revisions"}],"predecessor-version":[{"id":8231,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/8226\/revisions\/8231"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=8226"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=8226"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=8226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}