thoven0215
Member
I just put in my shunt regulator upgrade, and there seems to be hum in the right channel. The voltages at OA and OB are both near 380 instead of 300-305, and KregB is at 10 instead of 2.5-5. What could be the issue?
Right Channel Hum [resolved]
- Thread starter thoven0215
- Start date
We definitely don't recommend listening to an amp that doesn't pass its voltage checks.
Do you have the +Reg to Breg jumpers installed? If so, can you post some build photos?
Do you have the +Reg to Breg jumpers installed? If so, can you post some build photos?
thoven0215
Member
There's a Kreg on the A side and a Kreg on the B side. It's unlikely that they are both between 1-2V when one of your regulators appears to be working and the other isn't. Can you post the actual voltages for Kreg A and Kreg B?
thoven0215
Member
Oops I omitted the B. Kreg A is at 5 Volts and Kreg B is at 1-2 Volts.
There's a 50/50 chance that if you replace the 431 regulator on the low side, everything will snap back into place and work properly.
thoven0215
Member
I do not have an extra regulator to replace it. Should I contact the replacement parts email?
Yes.
thoven0215
Member
I replaced the regulator, but the problem still persists. All the values still measure the same as I last stated. What do I do next?
What voltage do you see a KregB? If it's still well below 2.5V, I'd want to see the bottom of the C4S/Regulator PC board.
thoven0215
Member
I would give it another shot. Do you remember which connection wasn't where it was supposed to be?
thoven0215
Member
Yes, I put it in the hole above OB (when you orient the letters correctly). I tried soldering everything back in and testing the voltages, but it started smoking. I unplugged and saw that it seemed to be the resistor next to the capacitor on the B side of the board that was smoking. It appears cracked now. What should I do?
thoven0215
Member
I can't seem to post the images, so I will keep trying until I figure it out
thoven0215
Member
Pics
thoven0215
Member
Other pics
Does the 2.49K resistor still measure 2.49K?
thoven0215
Member
My apologizes for the late response, came back from a trip and had a case of covid. The 2.49 resistor measures at around 0.08 now.
I would start by replacing that part and the TL431 on that side as well.
thoven0215
Member
Did you mean the LM431 regulator? I looked at the parts list for the shunt regulator and only saw the LM431 and no TL431.
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