This Chase RLC-1 Remote Line Controller can do exactly what you want. You must have a remote, no controls on the unit
Use it with your existing preamp, and then ANY simple tube preamp, new or vintage with no remote controls, no special features on the preamp, just preferred sound.
I just sold one of my spares to an audiophile friend after he determined, like me and my friends, you cannot detect if it is in or out, it’s 120db S/N is true.
4 inputs, remote: input; volume; balance; mute; treble; bass
It has two pairs of outputs, (front, rear) identical, from the early era of quad, simply 4 speakers, no processing, so you can use 'rear' for your sub, for a self-powered sub with it’s own crossover.
remote has a fader controlling the two identical outputs (front, rear)., so you could remotely adjust the sub’s volume relative to the main output.
I use one for all it’s features, one for remote power only, and:
I am using one downstairs in the garage/shop system’s receiver’s processor loop, gives me remote power, volume, mute, everything else goes into the preamp normally. That puts the RLC-1 in control only when using the processor loop.
