After looking at a product online called the "Cab-Link" by Radial Engineering, I decided to repurpose some old parts I had in my closet. I have two 4 ohm speaker cabinets, a 2 x 10 I built for my Vibro Champ, and a 2 x12 from my Super Twin Reverb. I wired the jacks in series so the combined impedance is 8 ohms, which is correct for my Carvin Vintage 16, Sovtek Tube Midget 80h and Fender Deluxe Reverb. Since I already had RCA jacks in the old box I had made for something a long time ago, I wired one up because the cabinet for my Vibro Champ is wired with a RCA plug (since that's what the output jack on the Vibro Champ uses). Of course I would only plug two cabinets into the box at any one time, a quarter inch and a RCA, or two quarter inch.
With room for additional jacks in the box, I thought about also making a parallel circuit, but don't have a need for that right now.
I've yet to test it out, I will measure the DC resistance with two 4ohm cabinets plugged in to double check.
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