I'm new here and to the tube world and recently decided to try one that came up for sale. I purchased a VTA ST-120 that looks amazing and it has been working great. I knew there was a possible issue with it as disclosed by the seller in our discussions and thought this could be a great way for me to learn about tube amplifiers by jumping right in. Not sure that's always a wise course of action but I decided to do it.
Here's my issue. The amplifier was working great until a few days ago when I began hearing a scratchy sound coming from the right channel that increases and decreases in volume somewhat randomly. It subsides sometimes but then comes back. I've tried swapping power tubes and interconnects which didn't make a difference. This is VTA ST-120 kit that the seller bought from VTA earlier this year built himself.
Any thoughts or help from the members here would be greatly appreciated. Thanks!