Just remember preamp out is variable outputGood call @millercarbon. That's something very important that I had overlooked.
A question though?
Then just remember if you do try and monitor using the power amp the signal coming off the tape deck is driving the power amp.When using the Preamp out, doesn't that take the amp out of the system? IOW disable it? I would think so, unless using Y adapters. But I cannot see any advantage to that. He should be able to moniotor it with the tape deck headphone output. What am I missing? Thanks