I have a pair of 4P1L\/4\u041f1\u041b dated 1968 which are properly burnt in. I’ve used them lately in my previous preamp incarnation with great results. <\/p>\n
The circuit doesn’t need explanation, I think I’ve covered this repeatedly for a long time. I will only point out the differences:<\/p>\n
The main change was fitting a pair of Russian wirewound 27\u03a9 resistors in parallel to get closer to the 15\u03a9 used in this position. I found these Russian wirewound resistors to sound extremely well as filament bias resistors. I tend to be skeptical about the “sound” of some components in circuits, however, they do make a big impact in the cathode of a filament bias arrangement. <\/p>\n The gyrator has my preferred combination: IXTP08N100D and BSH111BK. I have now an upgraded PCB Rev07 which fits the BSH111BK and similar FET and I will offer them shortly. <\/p>\n The latter benefits from the 30mA idle current. The result is lower output impedance whilst providing a great frequency response overall.<\/p>\n M3 needs a proper heatsink, it does get hot with about 2W of dissipation. <\/p>\n Well, this valve has the reputation of amazing performance and low distortion. The gyrator setup provides the best out of this valve in my view. You can get a flat response as well as great bandwidht from 10Hz up to 3MHz loaded with 100k\u03a9:<\/p>\n The distortion is very low and is lower than 0.05% below 10Vrms. Dominant H2 with a lovely harmonic profile characteristic of this valve. <\/p>\n i’ve been listening and using this valve extensively since 2011<\/a>. I have to say that it sounds amazing. I never get tired of its sounds. Before I listened to a 4P1L-4P1L system and found a slight edge on the sound (probably due to its H3 component) which I don’t hear on my system. The drive, clarity and tone is amazing. It can drive the 4P1L PSE perfectly well and you get a strong and clear bass. Very powerful. My +600 hours 4P1L are very quiet in this setup, no microphonic noise. I don’t have even dampers in the 4P1L sockets!<\/p>\n Anyway, if you need 19dB (x9) gain in your system or you need a driver for your SE amp, then this is the valve to go. I Still can be found cheaply and is a great contender to the thoriated tungsten filament DHTs like 01a<\/a> and VT-25.<\/a> <\/p>\n Build this one and enjoy!<\/p>\n","protected":false},"excerpt":{"rendered":" The return of the Siberian After trying out so many DHTs and pre-amplifiers, I decided to wire up my 4P1L preamplifier Gen3 and fit the gyrator board to drive my 4P1L PSE Amplifier. I have a pair of 4P1L\/4\u041f1\u041b dated 1968 which are properly burnt in. I’ve used them lately in my previous preamp incarnation … Continue reading “4P1L (4\u041f1\u041b) Siberian Gen4 – DHT Preamplifier”<\/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_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":[911,156,158,67],"tags":[782,537,703,319,142,595,215,625,864,903,982,875,1058,1059],"class_list":["post-6523","post","type-post","status-publish","format-standard","hentry","category-gyrator-pcb","category-pre-amplifier-valves","category-se-designs","category-thd","tag-4p1l","tag-4p1l-dht","tag-4p1l-dht-line-stage","tag-4p1l-gyrator","tag-4p1l-preamp","tag-4p1l-preamplifier","tag-4p1l-siberian","tag-bartola","tag-bartola-gyrator","tag-bartola-gyrator-pcb","tag-bsh111bk","tag-gyrator-pcb","tag-siberian-gen-3","tag-siberian-gen-4"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-1Hd","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/6523","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=6523"}],"version-history":[{"count":1,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/6523\/revisions"}],"predecessor-version":[{"id":6526,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/6523\/revisions\/6526"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=6523"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=6523"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=6523"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2017\/06\/4P1L-Siberian-Gen4-1024x995.jpg?resize=525%2C510\")
<\/a><\/p>\nHow does it perform?<\/h2>\n
![\"\"](\"https:\/\/i0.wp.com\/www.bartola.co.uk\/valves\/wp-content\/uploads\/2017\/06\/4P1L-Siberian-Gen4-FR-2-1024x500.png?resize=525%2C256\")
<\/a><\/p>\nHow does it sounds?<\/h2>\n