I have a stereo receiver upstairs for home theater and one down stairs for the same thing but with a turntable and preamp hooked to it. Can I use two Bluetooth receiver/transmitters to connect the receiver and wired speakers upstairs to listen to the albums I am playing on the downstairs receiver?
You can but how you connect the transmitter will depend on the the receiver.
If it has an analog audio output (could be zone 2 or front preamp out) you can use that,
If it doesn't have an output then you would split the output of the phono preamp and connect the transmitter to one set of outputs and the receiver to the other.
If you can hear the upstairs receiver down stairs there may be a delay that will drive you crazy if you play both receivers at the same time.