TOPIC: Tube Amplifier Questions--General and Technical
Tube Amplifier Questions--General and Technical
13 Dec 2017 15:23 #2557
I am not very familiar with tube amplifiers, but I do enjoy the sound. I have a Hamlin's 20-20 integrated amplifier, made by Trio, that is exhibiting some bothersome issues that I am hoping I can get some advice about. Here are my questions:
Speaker sound is present with the volume turned all the way down. The sound increases and decreases with increases and decreases in voltage inputs. For example, with the volume completely down, I can hear a higher volume of sound with a cd player selected that with a turntable. Or if I have an ipod connected, and the amplifier volume turned all the way down, I can hear sound from the speakers and increase the level of sound with the ipod volume. Is this normal, or should there be no sound with the volume turned all the way down regardless of input voltage?
There is a slight hum in the right channel. What is weird is that when I turn the volume up to the 12:00 position the hum decreases. The hum stays negligible as I turn the volume up until about the 2:00 position where it comes back. I am curious what the cause could be. If it is helpful for this question, I have attached the schematic.
The amplifier also has a slight noise in the form of a hiss that I would guess is normal in tube amplifiers. I am also guessing it is caused by the tubes. If I wanted to decrease the hiss, which (if either) would have a greater impact: replacing the 12AX7's or 12AU7's with a lower noise tube?
Thank you for any input!
I didn't find the right solution from the Internet.