{"id":87,"date":"2008-06-09T08:00:45","date_gmt":"2008-06-09T08:00:45","guid":{"rendered":"http:\/\/127.0.0.1\/wordpress63\/?p=87"},"modified":"2013-03-27T23:26:35","modified_gmt":"2013-03-27T15:26:35","slug":"experimenter-45","status":"publish","type":"post","link":"https:\/\/diyparadise.com\/w\/experimenter-45\/","title":{"rendered":"Experimenter 45"},"content":{"rendered":"

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Experimenter 45<\/span><\/h2>\n

This is by Matthew Reidsma in a past issue of
\nValves magazine. Circuit redrawn here.<\/span><\/p>\n

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Notice how simple the circuit is. The initial
\ncircuit calls for a cell of 1.2V but Matthew later revised it to 2.4V. You can
\nbudget the B+ at around 380V or more, depending on the DCR of the output
\ntransformer. By the way, Matthew used the Hammond 125E at 3k.<\/span><\/p>\n

The 0D3 or 0A2 can both be used. Any gas regulator
\nwill work as long as it gives 150V at the plate. You might prefer the 0D3 over
\nthe 0A2 for aesthetics reason.<\/span><\/p>\n

Note the idea of “tapping” or
\n“recycling” the output tube plate current to drive the input tube is
\nnot new here. Refer to similar circuits like Jeremy Epstein’s “Free
\nLunch”, “Monkey” and also “Direct Reactance”. Do a
\nGoogle and find out more.\u00a0<\/span><\/p>\n

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45? Do you have any idea how expensive
\nthis tube is?<\/span><\/p>\n

Yes, I’m aware of that. You don’t have
\nuse a 45 here, Can just substitute with a 2A3. Read other pages here to find
\nwhere you can get good value Sovtek 2A3s. Just be aware that filaments for 2A3s
\nand 45s are different so don’t go swapping them here and forth.<\/span><\/p>\n

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