Miscellaneous Projects

Please find inclosed pictures of my A75 monoblocks. I built them in 1995. The chassis is made of 1/4" anodized aluminum. You can see some influence of Alephs design. Transformer is mounted on the bottom and is separated from the rest of the circuit by the aluminum plate. Input stage has a separate regulated power supply and is mounted directly to the back wall in order to avoid wiring and make all the connections short. Trimpots on that board are accessible from the back through the holes in the chassis. I liked that in Aleph 0. One heat sink contains all the positive rail mosfets, the other contain the negative rail devices. Mosfets are mounted on custom aluminum bars which also support output board and capacitors. I used small Panasonic HFQ caps because I thought they are better sounding than regular electrolytics and also the current distribution is better if the caps are close to output devices, ESR supposed to be lower as well. (In the second monoblock I used different caps as you can see in the picture). As you can see from the picture I was so obsessed with the purity of design that I didn't used the screws to carry the voltage, but soldered pieces of Kimber wire to supply voltage to output devices. Both sides of the output circuit meet at the front mounted binding posts. I believe that this is more convenient location for big monoblock amp: AC connections and inputs in the back and output to speakers in the front following the signal path. All the resistors are Holco, wiring by Kimber and Cardas. Those amps have been running without any problem all those years. They idle at 50 deg C. The sound is beautiful. All thanks go to Mr. Pass who made that project possible. Peter Daniel aka HPotter

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