Calling all Supratek owners.....

Hi guys I have 2 questions regarding my Chardonnay..I do not have any paperwork on it so I am wondering what the toggle switch on the top in back between the silver transformers is for. When I switch it while playing music I don't really hear any difference. Also has anyone done a dact remote volume control mod, I just want to know if it fits. Thanks to everyone in advance.
I have a Sauvignon and the toggle on mine is an A/V pass thru.
I changed my volume control to a Dact. You get a nice improvement in openness but, you lose the remote control.
My preamp is highly modded so don't really know how much it was the Dact.
It is a beautiful piece and sounds great. It is a keeper!
On my Cabernet Dual, the toggle between the towers was a mute switch. I had a Chardonnay before this, but can't recall. I know there was a toggle switch on the Chardonnay for high gain and low gain of the 6SN7s.