• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Sanity check on B+ regulator

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Hello,

Before blowing stuff into little pieces, I'm going to ask before building... is the following regulator ok (nothing new here, it's a well known tubecad design) ? The only real change is the replacement of the TIP50 by a TIP152 (400V darlington with hfe of 200, see datasheet: http://www.datasheetcatalog.org/datasheet/mospec/TIP151.pdf ). The 40uF caps are mkp.

It will be placed after a 330-0-330, 85mA transformer and an EZ81, to provide 70mA@300VDC (headphones amplifier).

Thanks in advance for any comment.
 

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You're right. Under a 85m load, the xformer actually gave 415V. However, I'll add 100ohms resistors in serie with the plates of the EZ81 and that should drop quite a lot of voltage (there were none in the scope I've pulled it from). I'll also add a RC filter to get to 360V, whose value will depend on the actual voltages I'll get.
 
A cheaper way is to use a string of 4 100V/5W zener after the RC cell. They'll pull the voltage down at startup and will then sit completly out of the way afterwards.

I still wonder how bad that would be, considering the slow warm up of the rectifiers.
 
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