This resistor/speaker loading recommended for Taboo when listening to headphones worries me a bit!
From the little I understand of Steve's design notes, Taboo is a novel design. A side-effect of this novelty clearly is that loading the speaker outputs is recommended even though one would think they are 'out of circuit' when listening to 'phones. This implies there is some degree of interaction between the phones and speakers.
Now consider this: speakers - especially 2-way and up - present complex, frequency-dependent loads. This means the
simple, purely resistive load of your typical ortho becomes to some degree complex
Effectively, speakers connected to the Taboo become an added variable in tuning one's Taboo for phone listening! Added, that is, to the variables of tube choice.
This may be fun or this may be disquieting - certainly the latter for someone like me
Mitigating all this is that one-way speakers are likely to be connected, and probably present simpler loads than your typical multi-driver, crossover-based speaker.
My conclusion FWIW - I like the idea of a resistor much better as it's a much simpler load than a typical speaker and eliminates an extra tuning variable. [edited for clarity]
ps: And my Taboo started to sound a shade less good recently. It was also recently I substituted Kef Kit (2-way) satellites. Hmm...
