Hi I made my 45/2a3 amp just by placing 2 1500 ohm resistors together in parallel for the cathode in 2a3 mode for 750 ohms and with a toggle switch accuated it opens one of the 1500 resistors for 45 mode. For the plate load I just used a James 6123 output transformer with 2500/3500/5000 ohms taps and I just switch between 2500 ohms for the 2a3 and 5000 ohms for the 45.Filament trans is 2.5v @2.5a with a toggle and a small current limiting resistor for the 45. Sound quality as discussed before can be excellent for both the 45 and the 2a3.Regards Lou
Awesome, Lou! That's a great way to get that accomplished. I have a couple pairs of dual-primary OPTs, and I'll incorporate your trick when I get around to building my next amp. Thank you. ☺
Thanks for the follow up! Do you have a video discussing the differences between regular and mesh plates, or going further the various plate types? Thanks.
