How much hum is normal from a new tube amp
I just bought a great sounding Lab12 Suara KT120 tube amp. The issue I am having is a hum that is coming from the transformers. I can hear it with no music playing faintly from my listening position 12 ft. away. The question is, should I return it, or is this normal acceptable.
@elliottbnewcombjr Yes I meant to say KT150, that's what I have. I have rebiased all the tubes.The hum is present with the preamp off. I used the DB meter from my phone and tracked the loudest reading and it is coming from the back of the amp. I have also changed the power cable, and I just tried plugging it into a different socket. I checked the speaker cables. I have used all this equipment setup with different amps and they are dead silent. |
NONE. I have a few friends who tolerate 'some' hum. I tell them, something is wrong, find it or fix it. Years of 'some' hum later, they get it fixed, zero hum. ................................................. That amp says KT150 (you have a different version?) https://tmraudio.com/components/power-amplifiers/lab-12-suara-tube-power-amplifier/ does maker approve using KT120? (don't assume, I would verify) old post here: 2,658 posts The varying opinions of the KT150 tube seems to be primarily dependent on whether the amp was designed to utilize the KT150 in the first place. Since the KT150 needs a more stout transformer and has to run on a higher voltage," .................................................... Return is work and money, be thorough, MAKE SURE it's the amp. Get your Sherlock Holmes hat out of the closet. Switch tubes 1 at a time left to right, any changes? VERIFY it is not something else, i.e. only one device with it's own volume control, directly into amp to speakers (check speaker wires at speaker ends). One pair of previously silent interconnect cables with tight connections. Single device thru volume control (preamp if needed). Power from your normal (dedicated I presume) outlet. Change power to an outlet on a different circuit. No matter what: always hum, do you have an alternate amp to put in to verify the hum is definitely caused by the new amp before you pack it up? Same hum, I would return it! |
