Hi! I'm building a KA-Electronic Flat MC Preamp, and plan to place the amp in one box, and the transformer and rectifier board in another box. I also have a DIYINHK regulator board, but I'm not sure which box would be the best to place the regulator in? The regulator is linear. In the below picture the regulator is placed in the psu-box, but noise wise maybe it is better to move it to the amp-box?
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I think it makes very little difference as long as everything carrying large hum currents - transformer, rectifier, main power supply capacitors - is kept far from the amplifier, and the loop areas between the wires from the supply box to the amplifier box are kept small.
Keep regulator as close as possible to the preamp board. So I think regulator and preamp in the same box is better.
I assume there is at least 1uF decoupling capacitor at the input of the regulator.
I assume there is at least 1uF decoupling capacitor at the input of the regulator.
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The distance between the boxes will probably be about 1m. I`m was a bit concerned that hum currents and field from the transformer can couple over to the umbilical cable between the boxes. Maybe nonsene..
When you put the regulators in the amplifier box, their input lines, which have ripple on them, have to enter the amplifier box. With the regulators in the supply box, they don't.
With the regulators in the amplifier box, any disturbance picked up by the cable between the supply and the amplifier box is suppressed by the regulators. With the regulators in the supply box, it isn't.
With the regulators in the amplifier box, the supply impedance that the amplifier sees is determined by the regulators. With the regulators in the supply box, by the regulators and the wires between the boxes.
That is, each of the two choices has its minor advantages and disadvantages, but the main thing is simply to keep the transformer away from the amplifier, which you do in either case.
With the regulators in the amplifier box, any disturbance picked up by the cable between the supply and the amplifier box is suppressed by the regulators. With the regulators in the supply box, it isn't.
With the regulators in the amplifier box, the supply impedance that the amplifier sees is determined by the regulators. With the regulators in the supply box, by the regulators and the wires between the boxes.
That is, each of the two choices has its minor advantages and disadvantages, but the main thing is simply to keep the transformer away from the amplifier, which you do in either case.
Of all numbered concerns this is the most important in my opinion. At least for low powered preamp like in this case. Of course, in some situations priorities might change.
Thanks for all answers! I'll try it as shown in the picture, and have the possibility to move the regulator later if necessary. I also had a look at the Pearl II psu and grounding arrangement. Interesting with the rectifier bridge between the box chassis and ground.