I have an Audio Innovations 300 first generation amplifier with good sound. I have always wanted to use it as a reference to make a clone, reduce its size, and make some other changes: the original 120R cathode resistor was shared, and I changed it to four independent 240R resistors. The preamplifier and ink cartridge amplifier are powered from B+to increase reliability. DC280V is powered by a voltage regulator, and the schematic diagram of the regulator is from ARC, using operational amplifiers as servo adjustments+ 280V is approximately 150MA of current. Four ECL86 PCL86 heaters are independently powered, making it convenient to replace different vacuum tubes, with a voltage of 6.3VOR13.V
Also, I would like to ask you a question: When adjusting the operating voltage of each testing point, do I refer to the actual voltage tested by the original amplifier, or to the voltage indicated on the original factory drawings? Because the actual test voltage of the original amplifier is different from the voltage on the drawing, it has caused me to have doubts.
Also, I would like to ask you a question: When adjusting the operating voltage of each testing point, do I refer to the actual voltage tested by the original amplifier, or to the voltage indicated on the original factory drawings? Because the actual test voltage of the original amplifier is different from the voltage on the drawing, it has caused me to have doubts.
Voltages depend a lot on the specific tubes. They should not be too far off if the tubes are in a good condition and matched. How different the voltages are?
Hello jcalvarez, this is the voltage parameter I measured on the original amplifier.
HI Kriengim, I don't know how to accurately measure the output AC noise. I put my ear to the speaker and can hardly feel the noise, as if it's not powered on.