shinewu
New Head-Fier
- Joined
- Jan 28, 2004
- Posts
- 31
- Likes
- 18
The amp's details can be found here: https://littledotus.com/?product=ld-y2
This is my most expensive audiophile equipment purchase. The humming sounds are driving me crazy. So I tried a few things to diagnose:
1) The hum is NOT affected by the volume knob at all.
2) The hum on the balanced output is MUCH higher than it on the single ended.
3) As usual, the hum is not audible with low-sensitivity headphones such as Hifiman HE6SE V2. But it is crazily loud on Sennheiser headphones, which are much more sensitive.
4) I can also hear some very low hum from the power unit transformer. But should not affect my audio experience after putting on the ear cups.
5) When the amp is turned on, I can hear very faint hum. But after maybe 10-20 seconds, I can hear a very consistent motor like hum. This seems to suggest that the tubes are most likely the reason?
6) The hum is stronger on one side. I tried switching the pre-amp 6SH7 tubes, and I can tell the hum stronger side is also switched. Haven't tried switching the 300B power and rectifier tubes yet.
7) I tried both single ended and balanced inputs, the hum remained the same. So it is most likely not grounding issues.
Any help will be greatly appreciated. I really like the sound of this unit. At first, it feels very analytical. But when the sweet vocal kicks in, it is something to die for, just not the hum.
This is my most expensive audiophile equipment purchase. The humming sounds are driving me crazy. So I tried a few things to diagnose:
1) The hum is NOT affected by the volume knob at all.
2) The hum on the balanced output is MUCH higher than it on the single ended.
3) As usual, the hum is not audible with low-sensitivity headphones such as Hifiman HE6SE V2. But it is crazily loud on Sennheiser headphones, which are much more sensitive.
4) I can also hear some very low hum from the power unit transformer. But should not affect my audio experience after putting on the ear cups.
5) When the amp is turned on, I can hear very faint hum. But after maybe 10-20 seconds, I can hear a very consistent motor like hum. This seems to suggest that the tubes are most likely the reason?
6) The hum is stronger on one side. I tried switching the pre-amp 6SH7 tubes, and I can tell the hum stronger side is also switched. Haven't tried switching the 300B power and rectifier tubes yet.
7) I tried both single ended and balanced inputs, the hum remained the same. So it is most likely not grounding issues.
Any help will be greatly appreciated. I really like the sound of this unit. At first, it feels very analytical. But when the sweet vocal kicks in, it is something to die for, just not the hum.
