Hi,
My shunt using a 330 Ohm works very reliable. Most power is dissipated by the resistor. However in only 2 minutes a lot of heat is generated. That’s why I looked for plan B, as suggested by others above.
Today I tried series regulation with the 20N60S5 N-channel MOSFET, using zeners to get 600 Volt B+ max. So far so good, I ran my test with and without a load of 3 pcs. 50 Watt halogen lamps in series. The B+ is stable within a few volts. The MOSFET dissipates only 5 Watt with this load, so a higher load, as presented by my tubes, will be possible.
Regards, Gerrit
My shunt using a 330 Ohm works very reliable. Most power is dissipated by the resistor. However in only 2 minutes a lot of heat is generated. That’s why I looked for plan B, as suggested by others above.
Today I tried series regulation with the 20N60S5 N-channel MOSFET, using zeners to get 600 Volt B+ max. So far so good, I ran my test with and without a load of 3 pcs. 50 Watt halogen lamps in series. The B+ is stable within a few volts. The MOSFET dissipates only 5 Watt with this load, so a higher load, as presented by my tubes, will be possible.
Regards, Gerrit
The 'nice thing' is that with the series-regulated supply, you'll also realize a fair amount of ripple reduction, almost as if you had a series-choke in the power supply. You ought to have a capacitor tho', on the output (source side) of the series MOSFET regulator. This substantially increases ability of the supply to provide high current chunks as needed in real-world music playback.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅