Upgrade Nakamichi PA 7All power amp with mono blocks

@thriftyaudio here is a 180 for ya, if you are open to other ideas.  Since you have the SPL crossover now, have you considered trying the matching SPL Elector analog preamplifier instead of your NAD preamplifier?

My thinking is there is more to be heard from your PA7 and Acoustat 1+1s. Having owned Nak amps before, also noting a local colleague had a PA7 at his shop last month for refresh and a few upgrades. Still a relevant amp, imo. btw, I've had RA subs and the exact same DAC you have now, along with a cousin PASS / Stasis amp to yours, in my secondary system setup. Fwiw, I recently tested different tube and matching solid state preamps with mine. You might be surprised trying other preamps with yours.  

@thriftyaudio if interested, I can ask my local contact who worked at Threshold for Pass what his charge is to update your PA-7, or what he did on the last one I saw there recently.  Im really enjoying the upgrades on my other Pass Forte amp fwiw.  

Last two times I was there he had 3-4 Stasis amps there as I recall, plus a PA-7. Gotta ship to NorCal though. Super packing and double box and not cheap to ship but he gets amps from all over b/c people want to keep them in play.   

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@decooney thanks for the offer. My unit was refurbished two years ago.

Well that’s great, and hopefully you can find a good path for next steps. Admittedly,  I was a little hyper-focused on trying different preamps having heard your model amp and speakers (both) at different times, and some understanding of how can they can sound given a great source, DAC, preamp, cables, room etc. Best of Luck on whatever you decide.

@thriftyaudio given your existing investments so far, I like your plan for yourself on next steps. Since you indicated having just refreshed your PA-7 amp, go for it. Can’t think of a good reason not to try it with either unit you’ve narrowed it down to so far.

Fwiw, I normally run tube pre & mono amps on my main system. Late last year I picked up an older Pass/Forte amp, had it refreshed and upgraded. I’ve been listening to it swapping back and forth since. Channeling your own PA7 lineage that is. I like it well enough to keep it in play, and the tube gear has been sitting idle on the side. And as you know, some of this decision making also has to do with your speakers, but I can share without a doubt, a good preamplifier can really help the amplifier and your speakers to perform differently, hopefully better when you find a nice match and synergy.

As you may be aware, Darren Myers designed that Stellar Gold preamp before he left PS Audio to go join in at Parasound. I was eyeballing the internals and design on that unit, seems kind of like a unique and different design for PSA, lots of "other stuff", regulators, and discrete amplification stages fed by a big transformer in that unit. It might be worth a call over there to PSA to ask them what kind of serious demo they’d let you do, for 30-45 days, ensuring its a "good match" for you and your PA7 before committing to follow through on keeping it. Demo required imo!

Interested in hearing what they do for you. Would be nice to see PSA put their money where their mouth is on this one for you, if you decide to demo it. Best of Luck on whatever you decide.

"Fact is it's a tough combination to beat no matter what your budget is."

Reading back over this. Another thought along the same lines of thinking...

Yep, levarage the existing amp as-is, keep it for a few more years, at least.   Having owned the BF 2/64 myself, its an ok DAC for the money - yet more to be gained with a 1 or 2 level up dac for sure if you are looking for more lush velvet and musical sound.  Some dacs are "overly precise", too analytical for me, or imo.  

A really good DAC, nice Digi Coax cable, nice output interconnects to the PA-7 II, and you'll hear the existing amp and Acoustats in a new way.  Demo 3-4 more dacs first.  Try this for a while, might be pleasantly surprised.  

Then, after this is set up well, IF the new-amp-itch is still there for a set of "monos", start demoing (buy/return/keep) and comparing decent monos to see who can dethrone the recently refreshed PA-7 II.  Would not be suprised if it holds its own.  

@thriftyaudio I see so you’ve partly been down the dac merry-go-round. I ended up leveraging a bunch of friends and colleagues to narrow down my lists a bit more. You or others might prefer something different in terms of DACs, I was following along with folks at Schiit for while, and almost went down the Yggy path, yet had some insight to go a different way, and was trying to stay a way from a huge dac footprint, and a few I compared with that owned Yggy had downsized to BF 2/64. Dont get me wrong that dac has decent deail, separation, just not the velvet and musicality I was looking for. (note: I’ve had modded MHDT Labs tube tube dacs before as well). Note Schiit Yggy, probably a little smoother yes, yet maybe a different sound from BF 2/64. For streamers, nothing special, an older/updated Arcam unit I won’t let go of, and have compared it to a few different Bluesound Node units through friends. I was looking for a particular result, and a certain magic for my modded Pass/Forte SS amp and my upgraded Quicksilver Mono 120 tube amps. This eventually came about through my Border Patrol SE-I dac with the upgraded power supply, specific phillips TDA1543 chip, and Jupiter caps that come with SE-I version. Its the only dac I’ve never modified or needed to. The Tube is not in the signal path, which I like for my needs - its part of the power supply circuit and you can turn the tube on/off for different sounds too. Gary Dews built it for me and super happy pairing it with my particular pre/amp system setup. It responds well to different cables, and now my digital woes are over. Have not looked back since. Some people try it and rotate it too fast without letting it fully settle in. After 45 days of solid play time, it opened up more, and it bested my other dacs in a nice way. Let me say its a "preference" thing, and does what I want and need for my system.

I do believe so much of this is system/speaker dependent and finding a good match for your current and demo amps in the way of the right dac for you can be a game changer. It was for me. 👍