Previously, I think there is a "short" or something of a resistor to the chassis which cause the noise when touches the capacitor. Using slight force to pull that resistor seem to solve the louder humming noise. But, for now, the softer humming, "eeeee" noise still there.
As I suspected that noise maybe cause by the toroidal trans, I used an external power (switch-mode PS) to supply the power to the circuit. No noise at all. Then, connect another power source from the wall to the toroidal trans without connecting to anything (cap, bridge rectifier) and that humming, "eeee" noise started to surface. The noise goes away as I moved the trans away from the circuit. It getting louder as it goes nearer the circuit and tubes. As I had already fixed the position of the tube with drilled holes, it is too late to change the position now. Anyway, the conclusion is the interference of the toroidal cause the last bit of the humming and "eeeee" noise which I think cannot get rid of without re-positioning the trans further away from the circuit. It has to be out of the chassis in-order for the noise to be gone.
As for the grounding, I will still try to improve on it to the right concept of grounding as you and the rest had advised here. For now, I may try to use a simple switch-mode power supply or come to worse; change to another bigger chassis so as able to place the toroidal trans further away.
During my simple test, I had noticed that this toroidal trans had to be about 6 inches away from the circuit in order not to introduce noise to this amp's circuit.
Quote:
Originally Posted by fran /img/forum/go_quote.gif
Did you have any success with the grounding? Its just that when you mentioned about the noise going when you touched the caps. Thats kinda typical of the wierd crap you see with oddball grounding.
I had a number of similar issues on various builds - always came down to grounding! I know its such a pain in the ass.
Fran
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