I explain you the reasons of my question:
in the separated PSU there's a voltage stabilization on the negative rail, where all users (phase splitter and power drive) have big AC impedances and so huge noise rejection, while the positive supply is not regulated and around +15V. Isn't more reasonable to stabilize the positive power-drive rail to EG 24V and let the negative have more ripple?
B+ cap can be bigger in the dedicated PSU board due to space constraints in the original PSU (25 mm diameter maximum) but this can be solved with some tricks on the original board, or simply by increasing the space for the capacitors from 25 mm to 30 mm.
On my amp I've used 460V B+, 6k6 loadline with 23% UL. Shunt feedback is 39k and the phase splitter is loaded with 270k instead of 220k.
The 6k6 Raa vs 4k3 helps to have a better DF (and lower peak current requirements, so lower capacitance on PSU are fine) while the higher voltage and lower UL tap permit to have more power and a flatter loadline for the phase splitter with the 270 kOhm without sacrifying the driving current (so the slew-rate).
in the separated PSU there's a voltage stabilization on the negative rail, where all users (phase splitter and power drive) have big AC impedances and so huge noise rejection, while the positive supply is not regulated and around +15V. Isn't more reasonable to stabilize the positive power-drive rail to EG 24V and let the negative have more ripple?
B+ cap can be bigger in the dedicated PSU board due to space constraints in the original PSU (25 mm diameter maximum) but this can be solved with some tricks on the original board, or simply by increasing the space for the capacitors from 25 mm to 30 mm.
On my amp I've used 460V B+, 6k6 loadline with 23% UL. Shunt feedback is 39k and the phase splitter is loaded with 270k instead of 220k.
The 6k6 Raa vs 4k3 helps to have a better DF (and lower peak current requirements, so lower capacitance on PSU are fine) while the higher voltage and lower UL tap permit to have more power and a flatter loadline for the phase splitter with the 270 kOhm without sacrifying the driving current (so the slew-rate).
The separate PSU has a delay function too, so I suppose that is one difference.
I think it was still a WIP when Marc was ill, so perhaps it is ripe for a revision. There were also some small mods that had to be done to get it to work as designed.
I quite like the separate PSU. it was tailored for a specific Toroidy power transformer, so I had thought it could be used as a generic supply for different designs, or a point to point version.
I think it was still a WIP when Marc was ill, so perhaps it is ripe for a revision. There were also some small mods that had to be done to get it to work as designed.
I quite like the separate PSU. it was tailored for a specific Toroidy power transformer, so I had thought it could be used as a generic supply for different designs, or a point to point version.