Naim NAC72 729 time aligned boards

[Jean Mutchmore]

I currently use an Avondale Audio 821 preamp with RSL boards and Hicap with TPR4.
I am considering the purchase of a nac72 and would like to know:

1. what is the purpose of the 729 time aligned boards in it
2. what would be the effect on sound if they are removed from the preamp (only with the 321 RSL boards)
3.would the RSL 729 be an improvement on sound quality

System is NAT01, CDS1, Avondale Audio 821 with RSL boards, Hicap with TPR4, Bryston 14B3, Proac E.B.S.

 

[trick cyclist]

To clarify, you currently have an AA821, but have removed the output boards in preference to RSL ones, which usually inhabit Naim shoebox amps?

 

[jimbot2.0]

I never quite knew what 729 boards were for, electronically speaking- improving them reaps big benefits.

In my previous NAC72 removing the 729 (in combination with installing 821 cards) made it lose some of the ‘snap’ and timing of the 72 - although with increased clarity. I bought a tweaked set of 729s from here many moons ago and ran them with standard 321 cards with great success. Ifelt it was an improvement.

I later went the whole RSL route and before i sold the 72 on to move to a 52 had settled on running it with the RSL 321s and 729s- powered by a Teddy Supercap. Very nice indeed. Think i still have the cards somewhere.

 

[MJS]

The 729 is just an active filter buffer board. It came into being with the NAC72 and the proliferation of CD players and I guess was Naim's idea of preventing any HF mush getting to the amps. The 324 it replaced is a simple wideband buffer card. Both are necessary to drive the volume and balance pots although most modern low impedance sources would do it if you cared to link them out. The 321 is the gain stage and Naim 'miracle circuit' where a lot of the house sound originates. The 821 is ridiculously clear but it sounds nothing like Naim's. Neil and Ryan's cards build on the Naim sound I believe.

 

[jusphish]

I just replaced the original NA321 boards in my NAC72 with 821AR and I will say the following: the hiss from my speakers is completely gone, the gain is a little lower so I can use more of the volume control, and overall presentation is more clear. I am incredibly happy with this upgrade. Although it was pre-owned, it still cost more than half of what the NAC72 did, although not much more than a service would have. I cannot really say it has changed the character of my system aside from what I've already written. Some people may have a better ear for what is and isn't the Naim sound... but it seems to me that neither the original nor the replacement boards are highly complicated.

 

[dspatterson]

I wondered if my preference of the 32.5 to the 72 was down to the 324/729, I can't remember if I ever subbed the 324 into 729 position on 72 and if its was a backward step

 

[Gervais Cote]

From all the Naim preamps I ever heard, the 72 is by far the absolute best value for money followed very closely by the 32.5. Even more true when upgraded with Avondale or Neil Jadman’s cards IMO.

 

[Howdy]

I have tried Naim NA321 & Neil's NJ321 and NA324 & NJ729 & NA729 in NAC72.

I preferred the Naim NA321 & NA729 combination.
NJ sounded "cleaner", but NA were more fun. So I didn't consider Neil Jadman’s boards a straightforward upgrade.
I think NA729 especially form the essence of NAC72 or Naim olive sound.

I've recently acquired RSL Z250V but I can't comment on them because I also changed the power amp and the flat at the same time.
RSL 301 are now already 3 weeks on their post-brexit journey to my address.
Since I tried RSL MM boards in the past, and they were quite spectacular, I believe RSL boards could beat the NA. We'll see. One day.