{"id":7769,"date":"2019-03-01T20:50:38","date_gmt":"2019-03-01T20:50:38","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=7769"},"modified":"2019-03-02T12:47:34","modified_gmt":"2019-03-02T12:47:34","slug":"300b-emission-labs","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2019\/03\/01\/300b-emission-labs\/","title":{"rendered":"300B Emission Labs"},"content":{"rendered":"

Back at the beginning of the year I purchased a pair of Emission Labs 300B<\/a> for my new amplifier version (still working on it). I own several 300Bs but was keen to try these out given their reputation.<\/p>\n

Jac from JacMusic<\/a> sent me a matched pair which I traced them with the eTracer:<\/p>\n

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

Lovely linear curves as expected. Here is the Spice Model I developed if you’re interested in playing with it:<\/p>\n


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

EML300B-Spice-Model<\/a><\/p>\n

You need about 140Vpp to push the 300B to full output power. Here is the operating point I worked out on my previous implementation:<\/p>\n

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

Yes it’s rather hot at 35W. With a Monolith Magnetics OPT of 3K2, you should get 8W when driven with 140Vpp. You can use this excellent driver:<\/p>\n

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

The D3a in triode mode is probably one of the few valves which can do 250Vpp without any issues and very low distortion. Below is a THD plot for 240Vpp which is impressive. You won’t get this level of performance if it’s not with a hybrid mu-follower. Here is the amplifier circuit:<\/p>\n

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

If you are interested in less gain and adding a pre-amplifier stage (e.g. like an 01a) then you can look at implementing the 6e6p-DR (or a 6e5p) like in my original design:<\/p>\n

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

I really like the sound of this valve and has a lower H3 component when driving large volts. See below:<\/p>\n

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

Here is a plot of the frequency response of the driver. Less gain of course (i.e. 30dB) but with great performance:<\/p>\n

 <\/p>\n

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

Alternatively, if you need more gain, one of my favourite drivers is the 6SF5GT<\/a>. This one can give you 40dB in sterling performance with a hybrid mu-follower (a.k.a. gyrator) topology. You need to bias the valve a bit higher than the D3a and similar triode-strapped pentodes. \u00a0Therefore the HT has to be increased to 450V. You can add a drop RC to feed into the 300B output stage (R3 and C2 below):<\/p>\n

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

Here is the frequency response of the driver stage:<\/p>\n

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

There are so many options to work on. Even the lovely Russian 6C45P triode (which is a wild oscillation beast) can be used at a gain of 32dB:<\/p>\n


\n\"\"<\/a>Amazing response as well. You need to set the anode voltage to 200V and the cathode resistor (un-bypassed) to 120\u03a9.<\/p>\n

For me this time round, I will build the 300B output stage separately so I can play with different drivers. Yes, I want to experiment as usual.<\/p>\n

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

Back at the beginning of the year I purchased a pair of Emission Labs 300B for my new amplifier version (still working on it). I own several 300Bs but was keen to try these out given their reputation. Jac from JacMusic sent me a matched pair which I traced them with the eTracer:<\/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":[5],"tags":[610,674,545,1203,1204,1206,1205,903,1195,1092,1201,1202],"class_list":["post-7769","post","type-post","status-publish","format-standard","hentry","category-valves","tag-300b","tag-300b-se","tag-300b-single-ended","tag-300b-spice-model","tag-6c45p-driver","tag-6e6p-dr-driver","tag-6sf5-driver","tag-bartola-gyrator-pcb","tag-bartola-hybrid-mu-follower","tag-emission-labs","tag-eml300b","tag-eml300b-spice-model"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-21j","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/7769","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=7769"}],"version-history":[{"count":3,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/7769\/revisions"}],"predecessor-version":[{"id":7796,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/7769\/revisions\/7796"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=7769"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=7769"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=7769"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}