The amplifier was made of old transformer, which was equipped with voltage to power TDA7294. Original PCB of the amplifier was cut off. Capacitors in signal path in the preamplifier were exchanged. The supply is made through the bridge.
Heat sinks were separated from the rest. Functions of two switches of pairs of speakers were changed. First one from the left switches the bar of speaker/headphone outputs. Another switch switches inputs (in original device – output and return of the connector). The first position is preamplifier connected with the power amplifier. The second position preamplifier and outputs for a pair of chinches/ input for the power amplifier TDA7294 and another pair of chinches. That means that two those devices can operate separately.
After the assembly and run, it operates correctly.
Housing:
Front panel was equipped with a chamfer, which after polishing looks nicely with the chamfers of new aluminum knobs. Another original solution is the backlight of scale made of LED strip glued into frame of the front panel.
Link to original thread -
TDA 7294 szybko, tanio i efektownie