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Single Ended power amplifier with type '45 triode (3)

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The mains connection and loudspeaker terminals are mounted on a copper subchassis behind a milled hole at the rear end of the oak chassis. This seems to me a right choice due to the reasonable amount of strength put on the mains connector when plugging in and out. The fuseholder is mounted inside the amplifier (lack of space at the rear side).
At the front side the hum pot for the '45 is mounted as close to the pins of the tubesocket as possible - the solderlugs are soldered directly to the tubesocket. Adjustment on the hum pot is done from the bottom to provide a "fixed look".


The 4606 needs an UV4 socket which is hard to find (for reasonable money), so I made them myself using wood (Bubinga). Wood has a remarkable good value in isolation, when dry ofcourse... I drilled holes about .1mm less in diameter than the tubes' pins and the tube clenches perfectly. In doing this, wiring has to be soldered directly to the pins which is an advantage but not when replacing the tube...
The filament voltage of the 4606 is 4.5 Volts at 1 Ampere and will give an inevitable hum when AC is used. The idea was designing an amplifier using Super E-cap as much as possible, so the filament voltage is rectified and BlackGate Nx in Super E-cap are used as capacitors. A hum pot is used since a reasonable amount of AC is still present because I don't want to use a too high value resistor in the pi-filter to avoid too much dissipation. Schottky diodes are used as rectifiers and the whole circuit is mounted on a piece of experimenting PCB which is located between filament transformer and tubesocket and screwed at the innerside of the chassis.



The supply capacitors are "hot-glued" to the chassis: removable but sufficient anchored for normal use. The grounding wire connects the mains receptacle to the metal housings of the transformers where star-grounding is used. The "0" of the high voltage winding of the powertransformer has a separate connection via the first capacitor, the only paper-in-oil, to the star-ground. Each pair BlackGate NH's have also a separate connection to this star-ground. Wire used for grounding is 2.5mm solid core copperwire.
A RikenOhm gridresistor is used and a Mills wirewound as kathoderesistor and (again) Super E-cap as kathodebypass. The '45 is coupled using an interstage which is mounted under beneath, between driver and powertube. Both tubes have their own (floating) star-ground which are connected to the minus of each circuits last powersupply capacitor. A Quantum Purifier "purifies" the mains voltage....



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