Lowrider, I also have a BHK 250 and it’s dead quiet. No hum or buzz emanating from it anywhere. And I have dirty power in NYC. I’ve tried it plugged in direct to the wall and in my power conditioners and it’s always quiet, either way.
Detecting “Dirty” Power
I bought a used BHK 250 still under warranty. It is plugged into a Denali S power conditioner. I heard a hum coming from the area around the tubes. I cannot hear it from my sitting position and it doesn’t effect SQ, but I want it gone.
I sent it to PS Audio; they tell me there is no hum and sent it back. They implied I mostly likely have a power problem and recommended some troubleshooting steps. I unplugged everything from the 250 and plugged it straight into the PS Audio receptacle. The hum is still there, but it is not as pronounced. A P15 power regenerator might fix the problem, but I want to know if I have a power problem before I do anything.
How can I determine the quality of the power coming into my house and out of the receptacle? FYI, the Denali is plugged into a PS Audio receptacle/dedicated 20 amp line. I have a whole house generator w/ transfer switch and whole house surge protector.
I sent it to PS Audio; they tell me there is no hum and sent it back. They implied I mostly likely have a power problem and recommended some troubleshooting steps. I unplugged everything from the 250 and plugged it straight into the PS Audio receptacle. The hum is still there, but it is not as pronounced. A P15 power regenerator might fix the problem, but I want to know if I have a power problem before I do anything.
How can I determine the quality of the power coming into my house and out of the receptacle? FYI, the Denali is plugged into a PS Audio receptacle/dedicated 20 amp line. I have a whole house generator w/ transfer switch and whole house surge protector.
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As others have pointed out, it sounds like a DC offset problem. I just fixed mine by adding an Emotiva CMX-2 for under $150 https://emotiva.com/products/cmx-2 No more amp hum. PS Audio used to make one called the "HumBuster" but no more. |
I installed the HumDinger; it made no difference. I replaced my VooDoo power cord with a new GR Research power cord. Each day when I first turned on my system, I put my ear close to the tubes and could hear a faint hum. After about 30 minutes, the hum was barely perceptible. The amp came back from PS Audio with new PsVane stock tubes. Because they sound better to me, I put my used Tungsram 7dj8 tubes back in. The slight hum came back. I put in a new set of Tungsram 7dj8 tubes. The amp was dead quiet. Hopefully, it will stay that way for a while. After 40+ years of SS gear, I'm beginning to understand even more how much I still don't know about tube stereo equipment. I started buying tube gear about 3 years. It's been an interesting journey. |
- 22 posts total