{"id":29,"date":"2013-04-26T11:06:31","date_gmt":"2013-04-26T09:06:31","guid":{"rendered":"http:\/\/www.verelec.nl\/?page_id=29"},"modified":"2013-04-26T11:06:45","modified_gmt":"2013-04-26T09:06:45","slug":"0-25w-pencil-tube-fender-princeton-style-amp","status":"publish","type":"page","link":"https:\/\/www.verelec.nl\/?page_id=29","title":{"rendered":"0.25W pencil tube Fender Princeton style amp"},"content":{"rendered":"

0.25 W Micro Verb Project<\/h1>\n

Some time ago I stumbled across a number of 6K1B Penthode pencil tubes. Having a bunch of CK5703 pencil tubes lying around I decided to design a simple amp with a single preamp (CK5703) and an the 6K1B as power tube. Just to determine if a simple headphone amp was feasible. The first experiments worked out fine and I decided to design and build a (c)Fender Princeton Reverb amp using pencil tubes. I wanted to have a working Tube reverb in it and a working tube vibrato.<\/p>\n

I used the original Princeton schematic and recalculated most of the resistor values as the amp works with 150V B+ voltage which is a lot lower than the average 400V+ voltages used in current guitar amplifiers. Also I had to redesign the Vibrato using a different tube. The CK5703 has a gain of about 17 which is to low to get a 3 stage Oscillator working (minimum gain 29). I used a CK5744 in this case which worked fine.<\/p>\n

For output transformers I used a couple of Hammond 125ASE transformers. Way oversized (3W) but they don\u2019t exist any smaller. For the power supply 2 transformers were used. One for the 6.3V filaments which I rectified and onve for the high voltage.\u00a0 I used a 2 x 25V in series and fed that into a voltage doubler. With the current loads, the voltages are around 150V.<\/p>\n

Here are some pictures of the prototype phase and the final amp.<\/p>\n

\"100_3391\"<\/a> \"100_3385\"<\/a> \"100_3310\"<\/a> \"100_3157\"<\/a> \"100_3154\"<\/a> \"100_3146\"<\/a><\/p>\n

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

0.25 W Micro Verb Project Some time ago I stumbled across a number of 6K1B Penthode pencil tubes. Having a bunch of CK5703 pencil tubes lying around I decided to design a simple amp with a single preamp (CK5703) and … Lees verder →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":27,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/www.verelec.nl\/index.php?rest_route=\/wp\/v2\/pages\/29"}],"collection":[{"href":"https:\/\/www.verelec.nl\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.verelec.nl\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.verelec.nl\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.verelec.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=29"}],"version-history":[{"count":3,"href":"https:\/\/www.verelec.nl\/index.php?rest_route=\/wp\/v2\/pages\/29\/revisions"}],"predecessor-version":[{"id":43,"href":"https:\/\/www.verelec.nl\/index.php?rest_route=\/wp\/v2\/pages\/29\/revisions\/43"}],"up":[{"embeddable":true,"href":"https:\/\/www.verelec.nl\/index.php?rest_route=\/wp\/v2\/pages\/27"}],"wp:attachment":[{"href":"https:\/\/www.verelec.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=29"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}