Hello I am glad you like the amplifier. The transformers are from Leszek Ogonowski transformer in EU. The transformers are built on amorphous cores. Thank you for your appreciation.

Thank you for your comments, I'm glad you like it. I downloaded the parts list from SunkieDesigns. I changed nothing except the volt meter. I cheer you Henyk

Hello, anyone interested. Just finished building the 300b amplifier following the helpful SkunkieDesigns tips. I checked, I measured all the voltage and currents - everything is correct. The sound from this 300b amp is phenomenal I couldn't stop listening to the amp until late at night. I include a photo amplifier 300b on top Good luck to everyone in building the 300b amplifier.