gres
Full Member level 4
It's a single ended vacuum tube amplifier works in clear A class on two pentodes EL84 and one double 6n2p triode ( russion equivalent of ECC83).
Amplifier with casing, transformers and details e.g. potentiometers are based on project from **broken link removed**
It isin't perfect, but i'm quite happy about that project.
Boards are made up in thermo transfer mode, tined by soldering machine (ofcourse chemic methode would be better) In lamp basis i put ultra bright blue LEDs, the same with sound level potentiometer and switcher. Volume control is made up of stainless steel, so as switcher.
Transformers are winded by me. It's a speakers construction with secondary winding mixed with primary winding for better quality.
Casing made up of zin plate. Feed with floorpan - alu conis. All painted in 6 thin black lacquer layers + 4 colorless.
Amplifier consist option of late start anode voltage - sound appears after about 35 sek. I made that on 1 transistor and condenser 4,7mF. Charge current limit is limited by potentiometer that can set delay time. When condenser is charge, transistor turns on the relay.
Another options:is possibility of switching between anode/ pentode modes ( switcher at the back), possibility of regulation negative feedback for both channels ( potentiometer at the back)
Hum is so low that you need to put ear to speaker with maximum amplifier level ( of course music is stop )
Sound is very good. Worm and dynamic, with full details, soft vacuum bass. Power is not amazing 2x5W but it's enought for home.
Better not to compare with transistor amp specially middle/ low class.
More information at http://www.elektroda.pl/rtvforum/topic1459059.html
