What is your target?
To build a clone of the Marantz, or to build a good 300W into 8ohms capable amplifier, or to build a good 400W into 4ohms capable amplifier.
All three targets require a different transformer and a different PSU and a different amplifier.
Choose your target.
Are you rebuilding the Marantz?
Yes,
starting almost from scratch. The condition of this is very poor ....
What is your target?...................... I want to clone Marantz 2600. But it will take some time until I finish to design this new layout ... I need, at least, finish this revamp...