Does that one have the patent number printed on the outside?
It's one wacky booger on the inside. The four 6BQ5 are wired in parallel. And they are in line with the antenna on receive. Makes the noisiest preamp you ever saw.
Has no actual "standby" circuit between the coax sockets. Has to be plugged in and turned on so you can receive.
And if I'm right, it has no 'standby' switch.
Got talked into adding a second relay to provide that missing "standby" circuit so the customer could power it off and leave it in the coax line.
Once.
73