zman01 wrote:Shannon,
Since 300B tubes would need higher B+ vs 6B4G, what if a builder chooses with a transformer with higher secondaries i.e. 360-0-360 vs PA-774 which is 330-0-330? Will the 6AX5GT rectifier be able to get the B+ to acceptable levels (380v-390v)? Any changes in the BOM for this?
The 6AX5GT could handle the voltages. The question is what voltages would be present on the power supply caps at start up. Since the 6AX5GT is an indirectly heated tube (and slow), I think you might be OK with a stock build. But that is the first thing I would keep an eye on.
Shannon