input pcb

for all Revox B77

If we cannot do without electrolytic capacitors, then the electrolytic capacitors always get bypass capacitors. We also only use high-quality electrolytic capacitors from Panasonic.

We at revox-online have revised the basic voltage divider at the input. A stable, clean base voltage is very important, especially with very small input signals. We split the top resistor into 82k ohms and 100k ohms and filtered it with another capacitor. If we do something new, then do it right! Why Revox didn't do this earlier is really beyond us. Two more components would have always worked!

As usual with us, the operating voltage of the individual amplifier stages is buffered separately. Even in the first stage, both transistors are buffered separately. The printed circuit board itself also receives a support capacitor.

There is also a lot of free space on the new circuit board. There are hardly any differences in structure and the circuit has remained the same. Only the power supply has been optimized many times. Each circuit board receives a backup capacitor. An LED indicates the presence of the operating voltage!

Separate ground planes, shielding planes for the right and left input channel and the output amplifier. The UB also come separately from a central point to the individual amplifiers. The new input board has wide traces and they are 70 µm thick.

A comparison is not necessary! You can exchange the circuit board 1:1. To do this, loosen the four rear housing screws and carefully lever the tape machine forwards out of the housing. Loosen and remove the shielding plate with two screws. Now pull off the old input board and plug in the new input board.