You may want to contact Michael Samra at Audio Asylum. He did some mods on a Supratek, and seems familiar with it.
It may just be a loose connection. I also did these mods to mine and my preamp sounds much better. Better than anything I have owned. Hope that helps.
Here's the mod thread and his name to email him.
http://www.audioasylum.com/cgi/t.mpl?f=tubediy&m=148308
It may just be a loose connection. I also did these mods to mine and my preamp sounds much better. Better than anything I have owned. Hope that helps.
Here's the mod thread and his name to email him.
http://www.audioasylum.com/cgi/t.mpl?f=tubediy&m=148308