I am considering constructing a multichannel amplifier using thermionic valves for amplification. Unfortunately, to match the high output impedance of these devices to the low input impedance of the ordinary speaker, the use of a transformer usually indicated -- and as tube amps have grown rare, transformers with the required characteristics [broad frequency response, &c.] have also become unavailable. I would really rather not buy defunct old tube amps and tear them down for their output transformers, particularly since they might not quite match contemporary ideas of "high fidelity" and could quite easily be full of PCBs and other toxins. Likewise, I am not certain that I would have much success winding my own. Has anyone any experience with this type of project? I do not want to commit any resources to it until I'm sure it can be done. On a side note, has anyone used transformers for matching an 8ohm amplifier to a 2ohm subwoofer, or anything of that kind? I notice that power losses from impedance mismatch show up as some people's major concern, and that is one solution. Thank you.