I have a dh 220 with Fantasia upgrades and turn on thump blockers , I have noticed a hum/vibration ever 45 seconds that last for about 5 seconds . It is not audible through speaker just at the amp . Any thoughts ?
If you have timed it as in your post a regular hum/vibration its possible coming from a piece of domestic equipment .
Of course it could be a HF oscillation ( higher than the audio band ) but I have never come across one every 45 seconds lasting for 5 seconds.
I take it this occurs with no music playing ?
Of course it could be a HF oscillation ( higher than the audio band ) but I have never come across one every 45 seconds lasting for 5 seconds.
I take it this occurs with no music playing ?
It could be some local piece of equipment drawing a large and asymmetric load from the line. That would add a DC component to the AC line, and it would make the amp's transformer "growl" during those times. I think this is what Duncan2 was saying...
I have a gizmo that addresses this:
Akitika Store
I have a prototype of the device that sits in a metal box with green 3-wire gazintas and gazoutas for US 120 VAC power. If you'll pay postage for back and forth (Medium Flat Rate Box), I'm happy to let you try it...just PM me for more info if you're interested.
I have a gizmo that addresses this:
Akitika Store
I have a prototype of the device that sits in a metal box with green 3-wire gazintas and gazoutas for US 120 VAC power. If you'll pay postage for back and forth (Medium Flat Rate Box), I'm happy to let you try it...just PM me for more info if you're interested.
Hafler Dh 220 hum
Thanks for all your advise the domestic devise got me thinking so I took the amp to my daughters plug it in to ac . I waited and waited and no hum . She is on a different electric source than me . I am on a coop electric and sometimes their voltage varies . I went back home plug it into a kitchen outlet it was still there but faint. I put it back in stereo cabinet while I was doing that I noticed a fax/copy machine that’s near in the room making a lot of noise so I turn it off . I turned on the amp and waited and no hum/vibration so I turned the copier back on and the noise was back . What a relief.
Thanks for all your advise the domestic devise got me thinking so I took the amp to my daughters plug it in to ac . I waited and waited and no hum . She is on a different electric source than me . I am on a coop electric and sometimes their voltage varies . I went back home plug it into a kitchen outlet it was still there but faint. I put it back in stereo cabinet while I was doing that I noticed a fax/copy machine that’s near in the room making a lot of noise so I turn it off . I turned on the amp and waited and no hum/vibration so I turned the copier back on and the noise was back . What a relief.