I have a Dynaco ST-150 solid state amp that sounds good except for a persistent low hum coming from the power transformer. This is a mechanical noise that doesn't come through the speakers.
The amp has new electrolytic caps and output transistors but is otherwise stock.
This article (https://www.pooraudiophile.com/2015/03/how-to-fix-dc-offset-and-transformer.html) and similar ones make me think it's a DC offset problem, but I'd like to be sure before I spend the money on a DC offset filter. Other possibilities might be that the transformer itself is bad, or that the level of hum (not very loud, but noticeable within a couple of feet of the amp with no music playing) is normal. I think my ST-70 hums a bit too, but I haven't used it in a while.
Thanks for any advice you can provide.
The amp has new electrolytic caps and output transistors but is otherwise stock.
This article (https://www.pooraudiophile.com/2015/03/how-to-fix-dc-offset-and-transformer.html) and similar ones make me think it's a DC offset problem, but I'd like to be sure before I spend the money on a DC offset filter. Other possibilities might be that the transformer itself is bad, or that the level of hum (not very loud, but noticeable within a couple of feet of the amp with no music playing) is normal. I think my ST-70 hums a bit too, but I haven't used it in a while.
Thanks for any advice you can provide.