The BX-300 is a beast. The first Nak I've ran with that makes everything sound good. The K75 isn't really comparable but it's no slouch.
What the Nak does that no Sony I've ever owned could is to make pre-recorded tapes sound almost like home-brewed ones. And my library of Metal Master mix tapes, spanning efforts dating back to 1992, play back brilliantly on it as well and those are all recorded with Dolby C. I attribute that bit of magic to the work ESLabs did. It also makes tapes that play back on the 870ES perfectly. No other Nak has been able to do that. It got the reel motor replacement and associated electrical mod, the cam replaced, critical recapping + other discreet components ... along with all the normal transport refurbishment most places do that specialize in Nakamichi work.
I figure I'm set now with that deck for a very long time.
What I don't like about the Nak is the metering. I'm use to how Sony does it's average 'attack', the peak hold stuff and the massive benefit of the granularity of the LED segmentation. In that respect, the K75 beats the BX-300 hands-down.
I'll probably use the K75 to do a bunch of LP recording on non-Metal stock & without Dolby ... and then mainly play those tapes back on the other two decks.
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In due time Lee. I want to do a video demo like Nando's done so well in the past ... but I need to make sure the audio recording part of that deal is up to snuff and sounds good.
And Hey ! At least I posted up that advertisement in the mean time...