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I believe it is available for 2005 spas as a new unit. I don't think it is practicle to go from SpAudio I to II.
I'm sorry, probably too many Sierra Nevada's today. I meant upgrading from nothing to SpAudioII not from SpAudio I to SpAudio II. My bad.
I promise: ONE OF THESE DAYS, I'm going to try a simple home stereo on a HS spa with the transducers. Those two componants are expensive enough as it is, but I want to try connecting to a simple home stereo.Mind you - this may not satisfy the ETL listing and it may somehow open the door to great and grevious bodily harm somehow - but I want to try it.I just hooked up our Spaudio II and ran it for the first time yesterday. It sounds much better: the Internal part is about the same, but as soon as you fade in the external speakers the 'brightness' which was missing comes back. And if you want to run the tub as the sub, it really pumps. Wow - what is that, about five puns in one?