My last effort....
A new amplifier using 100TH tubes in S.E. driven by 2A3 with interstage transformer.
Three tubes regulated power supply are used, one with 6C33C tube supply the power to the two 100TH and two with 6EM7 tubes (one per channel)are used for the driver and input stage.
Cabinet in solid wood.

Comments

• Ahura-Mazda
• 28 March 2016 at 01:24PM
• Beautiful work. I am gathering all the parts to make a 100th amp. I intend to run 100th at 650V b+ with 110ma through a 5k OPT with 16 ohms as cathode feedback. Grid bias will be around +35V and grid current at idle at 20ma idle. This will allow me to use an inverted interstage transformer to counter some of the current of the driver tube. I want to use 801a or VT25 as driver filament will be current source and starved at about 6.5 to 7V. The voltage gain tube will be 841 again with current source starved filament supply. 841 has a mu of 30. The voltage gain and driver can be loftin-white. Supply for 801A at interstage transformer primary will be 650V cathode at around 310v with 25 to 30 ma. 841 is CCS loaded at 4 to 5 ma from the cathode of 801 to create a safe loftin white. Tell me what you about this ides. I haven't started the project yet. You have experience with 100th. any tips or help would be welcome. By the way, did you also made an 808 amp? Woodwork looks somewhat familiar. Please contact me at zigaratt at h0t mail d0t c0m.