the modder 's diary part 07:
starteed to test and measure components. at least for the modded dc/dc step up converters i can say, that the devices get unstable above 55 volt and are rather inefficient, so i will not use them instead rebuiling new ones based on Shikada San's internal power supply board.
two nice and small se output transformers arrived last week:
they have a primary impedance of 4 KOhm 25mA DC current, so nicely fitting the specs of the tu-05, but best of all they have a secondary impedance of 125 and 500 ohms, so should be ideal for high impedance headphones like my hd800 or a beyer T1.
today finalized the basic design of the full battery driven power supply consisting of AC power supply / charger, DC battery driven PSU and the tube and other voltage regulators:
The AC power supply and charger will consist of an isolation transformer and then different transformers for left and right channel and auxiliary voltages plus primary voltage regulator stages / chargers with constant current.
The battery driven power supply that can be charged with the AC power supply consists of Li-Ion BMS balancer boards and Li-Ion protection circuit / charger boards and Li-Ion batteries (40 in total which means 40x 3,7 volt x 2,2 ampere = 325 Watt of battery power).
the different components and parts are desigend to get fully charged within 8 hours, so far away from the maximum charging speed but optimizing lifetime of the batteries and well balanced so that all the different voltages and so the whole amp have enough power for a battery driven runtime of at least 40 hours.
to provide always exactly the same voltages for the tubes independent of beeing in battery mode or just beeing charged, an additional voltage regulator stage is provided that can be placed directly under or nearby the tubes, so each tube has its own voltage regulators and any loss of voltage of the internal power main bus will be automatically compensated.
another benefit is that the amp can be driven only with the batteries, only with the AC power supply or combined with batteries while beeing charged.
the anode voltage power supplies can provide much more power than needed for the Dl92 tubes (to be honest up to 5 ampere per tube), the anode power supplies have a battery capacity of 62.5 watt per tube and as the df91 tubes don't need that much power, i would say more than 100 watt of battery power per output tube, should be sufficient to extend the amp with an even much more powerfull output stage.
Edited by GermanGuy - 12/2/13 at 6:17pm