Which outputs when using Pre as phono front end?

The tape outs will give a non-variable signal to your linestae, bypassing the preamp features (volume and tone control? circuits) of the preamp. If you use the pre-out as though connecting to an amp, you would have two stages of line amplification, useful only if it might help to have a volume control going in to the line stage to match levels with a cdp.

Paul

Phil- I don't know the circuit configuration of the FET2, but often the tape-out buffers were merely so-so op-amps. As the tape-out signals were seen as a convenience but not really valued sonically, these op-amps were less than stellar. If this is the case, then the main outputs would likely be preferable, though as Paul mentioned, there may be other sources of signal degradation to consider. The bottom line is whichever sounds best. Be sure to match the level of the two signals between the fixed tape-out level and the main out level when you do the comparison. Enjoy.