I am the one who had the pleasure of having John Chapman bring a NOH (I believe with the silver transformer wiring) over to try out with the Ack!Dak in my system. Sorry, I got in late into the discussion - I've been swamped at work the last week or so.
John has done a superb job of describing how the two synergize. I just want to add a few small points.
First, both the NOH and the Ack!Dak are superb products. I've heard a lot of pre-amps over the last few years - some in my system and some in others, but have yet to hear a pre-amp with the level of clarity and purity I heard from the NOH (more on this later). Similiarly with the Ack!Dak - I've been auditioning a lot of digital front ends some well past the Can.$10K boundary and of all the digital front ends I've heard there are only a hand full that I'd be able to live with - the Ack!Dak is certainly one of them.
So, what are my impressions on how the NOH - Ack synergized. First, let me say that my Sonic Frontiers Line 1 pre-amp with Amperex NOS tubes is strongly on the warm, full bodied side - a noticable coloration that I have lived with and enjoyed for several years. So, when I first heard John's TAP and later his NOH, it was a real eye opener as to just how coloured my pre-amp really is.
My first impressions of the NOH - Ack!Dak was of immense clarity, dynamic range, soundscape and frequency extremes - the kind of which my SF Line 1 could not match (in the case of clarity, it didn't even come close). But, I also lost the full-bodied midrange that my tube pre-amp with my selection of NOS tubes was imparting. So, initially my impressions were of a leaner presentation in the midrange too - I think this is what Marbles was describing. HOWEVER, after a few hours of listening to the NOH - Ack combination and letting myself adjust to the sound, I found that I no longer felt that the midrange was lean - it was accurate to the recording. Recordings with Piano with body in them sounded full-bodied, recordings with Piano with a leaner mastering (yes, the do exist
), sounded leaner.
As John mentions, I am partial to female vocals, so have quite a few CDs with female vocals. One of which I believed to have noticable hardness to the upper midrange that always prevented me enjoying it, when played through the NOH - Ack combination was absolutely stunning - there was absolutely no hardness to the voice - it was unfortunately an undesirable attribute being added by my SF Line 1. Finally hearing this recording in all its glory was one of those magical musical experiences we all crave.
We also played a number of fairly touch-and-go recordings and the NOH - Ack combination handled them extremely well. No, it didn't magically convert a bad mastering to a good one, but it did allow me to enjoy the music without constantly highlighting the faults - trust me when I say that this is no small feat - two very expensive digital front ends I heard made we want to run screaming from the room with my hands over my ears, on these recordings - they were that ruthless.
So, it all comes done to what your preferences are. If you want the warm, full bodied, midrange emphasis that a tubed pre-amp can give you, this is likely not the combination that you'll end up with.
Let me just finish off by saying that when I plugged my pre-amp back in after John had left, the warm, full-bodied, familiar sound was back, but a lot of the magic I experienced with John's NOH in my system left with him too.
