• 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.

DHT Headphone amp for HifiMan Edition XS

Joined 2009
Paid Member
Test filament reg. passed with 20R dummy load 13V = 650mA


  • 17177573625291133657279409601647.jpg
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Joined 2004
Paid Member
If the PT is 18VAC it's working.
18VAC 4P1L filament bias PSU.jpg
5.88V headroom is just enough for R.C.
If you want more headroom, decrease 10R to 8R.

Are you sure, that R.C. all component is OK?
Rset is 3R3//3R3.

If you tested the raw supply without R.C, the dummy load resistor value must be 27R.
17.7V/27R= 0.655A