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I have a Rotel RA-02 integrated preamp/amplifier. I modified it to have a main-in connection, like the old NAD integrated amps. For convenience, I shanghaied the "AUX 2" input connector for the purpose.
The reason is that I wanted to use the RA-02 with an external active crossover and a sub with a plate amp. Using the tape loop for that purpose requires continually adjusting the sub's volume separately from the Rotel volume. Not acceptable. So the crossover input is connected to the Rotel Pre-out. The high output of the crossover goes into the new Main-in connector (was Aux 2), and the low output of the crossover goes to the sub's plate amp. That way the Rotel volume control works for both the main speakers and the sub.
The sub's plate amp actually has a built-in crossover, but I found that the small main speakers sound better when fed through a high-pass filter. That way they are not trying to produce low frequencies, moving like crazy, but not moving enough air to be heard.
I had to order the schematic from Rotel, It was printed on an antique thina and flat object called "paper." It's probably packed away somewhere. But I'll venture to guess that a picture of the innards would suffice to show what I did. As I recall, it was just a matter of snipping a wire or two and running adding a wire between two points for each channel.
If someone who owns an RA-02 wants to give it a shot, I'll take the picture and post it.
The reason is that I wanted to use the RA-02 with an external active crossover and a sub with a plate amp. Using the tape loop for that purpose requires continually adjusting the sub's volume separately from the Rotel volume. Not acceptable. So the crossover input is connected to the Rotel Pre-out. The high output of the crossover goes into the new Main-in connector (was Aux 2), and the low output of the crossover goes to the sub's plate amp. That way the Rotel volume control works for both the main speakers and the sub.
The sub's plate amp actually has a built-in crossover, but I found that the small main speakers sound better when fed through a high-pass filter. That way they are not trying to produce low frequencies, moving like crazy, but not moving enough air to be heard.
I had to order the schematic from Rotel, It was printed on an antique thina and flat object called "paper." It's probably packed away somewhere. But I'll venture to guess that a picture of the innards would suffice to show what I did. As I recall, it was just a matter of snipping a wire or two and running adding a wire between two points for each channel.
If someone who owns an RA-02 wants to give it a shot, I'll take the picture and post it.