OK, I know my preamp is from the stone age. It's an ARC SP11 factory upgraded to MkII. I've had it for years, and love how it sounds with my ARC D400 MkII.
I recent returned from months of working out of town to a disturbing sound in the phono stage. The best way I can describe it is when I turn the volume up there's a sound similar to an electric tooth brush or one of those battery powered stylus brushes that were popular a few years ago. The whole system is on a dedicated power line with Richard Gray Power Company conditioning and the sound is not heard in the CD or tuner stages. The rest of vinyl playback system consists of a VPI Super Scoutmaster Signature, JMW arm with Nordost Valhalla tone arm cable, and a Lyra Helikon cartridge.
I've retubed in the past, and don't recall hearing this type of distortion at those time. Is it time to get another set of 6DJ8/ECC88's or do I have a larger issue to deal with.
Thanks in advance for your help.