I’m not sure that a preamp is heavy enough for the Jumbo DH cones. I thought they were recommended by GS for heavy components and speakers. I could see the high frequency exaggeration if used on lightweight equipment.
I use the small DH cones in combination with DH squares under my tube phono preamp and they definitely create a nice improvement in depth and width of soundstage along with a blacker background.
I use the small DH cones in combination with DH squares under my tube phono preamp and they definitely create a nice improvement in depth and width of soundstage along with a blacker background.