I have an integrated amplifier without pre-out connector. I want to connect this to another power amplifier, preferrably by completely bypassing the power amplifier circuits in the integrated amplifier.. How can I do this?

I see several options, each with its own issues:
1. Use tape-out, but I think this is not volume-controlled. True?
2. Use head phone output. I am not sure whether this output is internally connected to the pre-amp out, or to the power-amp out. In the last case the power amplifier is not bypassed. I am also not sure what the signal level on the head phone output is: is it line level or much larger?
3. Use output of integrated amplifier, and connect that - perhaps first through a resistor network to reduce voltage level - to input of 2nd power amplifier.

Any other ideas and advice welcome!