{"id":10628,"date":"2022-01-16T09:09:11","date_gmt":"2022-01-16T09:09:11","guid":{"rendered":"https:\/\/www.bartola.co.uk\/valves\/?p=10628"},"modified":"2022-01-16T09:09:11","modified_gmt":"2022-01-16T09:09:11","slug":"aa-dht-spice-model","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2022\/01\/16\/aa-dht-spice-model\/","title":{"rendered":"Aa DHT Spice Model"},"content":{"rendered":"

\"\"<\/a>About 5 years ago I built the first version of the Aa<\/a> DHT preamp. It looked like this:<\/p>\n

<\/p>\n

\"\"<\/a>This preamp sounded great (as you would expect with this DHT valve). As wrote before, with a gain of about 30 is ideal if you need the gain. More importantly, it’s timbre and detail is unique but is challenging to use. It has an internal anode resistance of about 30K\u03a9, so best topology is what I presented before as choke loaded is a real challenge.<\/p>\n

The filament bias configuration with the Russian wire wound resistor of 5\u03a9 is perfect drop-in. Later I tried the SiC bias configuration<\/a> which was also great.<\/p>\n

Recently I was asked for the Spice model. I thought I had posted it before, but I was wrong. So here it is:<\/p>\n

I traced the curves of a Valvo Aa valve which tested 97% (Ia=2.92mA\/1.09mS @ 220V\/Vgk=-2V):<\/p>\n

\"\"<\/a>
Aa triode curves<\/figcaption><\/figure>\n

And here is the manual fit of the DHT model:<\/p>\n

\"\"<\/a>
Aa DHT triode Spice model<\/figcaption><\/figure>\n

 <\/p>\n

Below is the model, and you can also download it from here:\u00a0Aa spice model<\/a>:<\/p>\n

**** Aa TRIODE Composite DHT *****************************************\n* Created on 10\/13\/2017 18:31 using paint_kit.jar 2.9 \n* www.dmitrynizh.com\/tubeparams_image.htm\n*\n* Traced and model by Ale Moglia valves@bartola.co.uk\n* (c) 2017 Ale Moglia and Bartola Ltd. UK\n* www.bartola.co.uk\/valves\n*----------------------------------------------------------------------------------\n.SUBCKT DHT_Aa 1 2 3 4 ; P G K1 K2\n+ PARAMS: CCG=1P CGP=3.5P CCP=1P RFIL=7.6\n+ MU=30.3 KG1=4740 KP=216 KVB=720 VCT=-1.33 EX=1.41 RGI=2000\n* Vp_MAX=350 Ip_MAX=8 Vg_step=0.5 Vg_start=0 Vg_count=11\n* Rp=4000 Vg_ac=55 P_max=1.5 Vg_qui=-48 Vp_qui=300\n* X_MIN=69 Y_MIN=51 X_SIZE=437 Y_SIZE=429 FSZ_X=1134 FSZ_Y=689 XYGrid=false\n* showLoadLine=n showIp=y isDHT=y isPP=n isAsymPP=n showDissipLimit=y \n* showIg1=n gridLevel2=n isInputSnapped=n \n* XYProjections=n harmonicPlot=n harmonics=y\n*----------------------------------------------------------------------------------\nRFIL_LEFT 3 31 {RFIL\/4}\nRFIL_RIGHT 4 41 {RFIL\/4}\nRFIL_MIDDLE1 31 34 {RFIL\/4}\nRFIL_MIDDLE2 34 41 {RFIL\/4}\nE11 32 0 VALUE={V(1,31)\/KP*LOG(1+EXP(KP*(1\/MU+V(2,31)\/SQRT(KVB+V(1,31)*V(1,31)))))} \nE12 42 0 VALUE={V(1,41)\/KP*LOG(1+EXP(KP*(1\/MU+V(2,41)\/SQRT(KVB+V(1,41)*V(1,41)))))} \nRE11 32 0 1G \nRE12 42 0 1G \nG11 1 31 VALUE={(PWR(V(32),EX)+PWRS(V(32),EX))\/(2*KG1)} \nG12 1 41 VALUE={(PWR(V(42),EX)+PWRS(V(42),EX))\/(2*KG1)} \nRCP1 1 34 1G \nC1 2 34 {CCG} ; CATHODE-GRID \nC2 2 1 {CGP} ; GRID=PLATE \nC3 1 34 {CCP} ; CATHODE-PLATE \nD3 5 3 DX ; FOR GRID CURRENT \nD4 6 4 DX ; FOR GRID CURRENT \nRG1 2 5 {2*RGI} ; FOR GRID CURRENT \nRG2 2 6 {2*RGI} ; FOR GRID CURRENT \n.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N) \n.ENDS \n*$<\/pre>\n
 <\/p>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
About 5 years ago I built the first version of the Aa DHT preamp. It looked like this:<\/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":[1430,1431,1170,632,1433,1432],"class_list":["post-10628","post","type-post","status-publish","format-standard","hentry","category-valves","tag-aa-dht","tag-aa-triode-model","tag-aa-valve","tag-bartola-valves","tag-dht-curves","tag-high-mu-dht-preamp"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2r2tK-2Lq","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/10628","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=10628"}],"version-history":[{"count":1,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/10628\/revisions"}],"predecessor-version":[{"id":10635,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/posts\/10628\/revisions\/10635"}],"wp:attachment":[{"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/media?parent=10628"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/categories?post=10628"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bartola.co.uk\/valves\/wp-json\/wp\/v2\/tags?post=10628"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}