Posted by PakProtector [ 152.163.100.65 ] on December 06, 2005 at 16:59:45:

In Reply to: Resistor choices for SV811 project posted by colinhester on December 06, 2005 at 09:16:10:

Hey-hey!!!,
Look at potential voltages across the resistors. Power dissipated by the resistor is V-squared over R, in watts. There is normal operating voltage, and failure or voltage excursions which increase the dissipation.

The Kiwame CF is a decent resistor, and reasonable as DIY products go.

The main PS capacitors should have small bleeders. The hot cathode of the front stage will do most of it, and the residual will be taken care of by your proposed values.

Have you looked at the data sheet for this valve? At B+ of 500, and grid voltage of 0, this triode is going to pass 150 mA. That's 75W of anode dissipation. Also, cap coupling a Zero bias amp looks a bit questionable to me. Clearly, I have not built this SE amp, or even played with one of these valves, but by the provided schematic, and Svetlana data sheet I have questions.
cheers,
Douglas

Replies: