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Difference between NAC 32 and 32.5 ?

Discussion in 'd.i.y.' started by PlattenFantast, Mar 14, 2007.

  1. PlattenFantast

    PlattenFantast TT user

    I've just joined this forum.
    Many moons ago, I had a Naim NAC 32.5/HICAP/NAP250 amp. Time passed and these were sold off, and I ventured into "vintage tube gear land".
    Still today, I can remember the music pump that my NAIM amp was, driven by LP12/Ittok/ASAK. Now I'm setting up a second music system and was thinking about trying more or less to recreate that, albeit in a more modest way, something along the lines of a NAC 32.5/110 and whatever recommendations for a good PSU that you might have, that saves me having to splash out on a s/h HICAP. I have been reading (PFM & Acoustica) about some superregulators (ALWSR), so I'm interested in what can be done with those please?
    I will be driving Linn KAN-1 or maybe LS3/5A with this amp.
    Also; I've been offered a NAC 32; what's the difference electronically and soundwise between a 32 and a 32.5? Many thanks? Really; any recommendation for a (best value for money) smallish and economical NAIM amp is greatly appreciated.
  2. laverda

    laverda pfm Member

    Hi Peter and welcome here.....its a nice place this.....

    Thinking, in a 'modest way' is always the best to start with. You can create a stunning sound with just the two boxes you mension, the 32.5 and the 110 are a great pair and with a nice power supply and a few tweekes (component changes) here and there you'll be delighted I'm sure.

    Also consider either the 42.5 (very cheap sometimes) or 62 & 92 pre amps, the 321 line stage circuits are the same realy and with minor mods these can better a 52 .

    Or do no modding to the pre but build a super power supply unit. Works for most every time...a HI-Cap is NOT up to the job IMHO and is easy to better for a bit of effort......

    I'm sure PFMers will be able to point you in the right direction........

  3. hacker

    hacker Delicious and nutritious

    Hi Peter, welcome to PFM :)

    The difference between a 32 and a 32.5 is that the 32 has one 24V power rail that powers the 2 gain stages, 2 buffer stages and the relay circuit (plus phono stage if you have one). The 32.5 has 2 seperate power rails - one for the gain stage/relay, and one for everything else.

    If you're going DiY, then you may as well take the 32 and convert it yourself!

  4. Robert

    Robert Tapehead

    Julian Vereker once said that there were bigger differences between batches of the same pre amp than between the 32 & 42. If you can manage on just three inputs a 45 (or 42.5) is a fine bargain and you can pick 'em up for as little as £50. I paid £60 recently for a mint 45.2.

    Converting either to .5 status involves a small cut in the pcb track, soldering a couple of wires and replacing a 4 pn connecter with a 5 pin version. Remember though that there is no benefit in running a dual rail pre from a power amp or single rail SNAPS.
  5. PlattenFantast

    PlattenFantast TT user

    Hello Graham and Carl and thanks for the welcome and the valuable input!
    I have been missing the speed and slam of my former Naim amps.
    If I recall correctly, I started out with a 42.5/110, upgraded to 32.5/110, 32.5/HICAP/110 and eventually managed to land an old 250 at a reasonable price. I rang up Naim HQ on the phone, and brought that 250 with me from Sweden, travelled down to Southampton and handed it in for a major update - a few days later it was ready for collection - superb service and very nice people. The thing about these "upgrading paths" as I recall it, (and yes, I can appreciate that many disliked them as an outright money sucking trick), were that I was a very happy listener before the upgrade, but even more so after; a win-win situation in other words. I also had new caps put in my HICAP. I then moved to the UK and ran into my first Garrard 401 Leak Stereo 20 based system, and that was an eye-opener in many ways. Still, and as mentioned earlier - the sheer musical drive and enjoyment that the Naims brought were quite special and I kind'a miss it at times. Loved the KAN-1:s too (;-) (eventually I got the Keilidh:s, but once at home, I instantly felt these were a significant downgrade from the KAN:s).
    Looking forward to try to get that smashing musicality back... NAIM style.
    Cheers again!
  6. andyr

    andyr Registered User

    Hi Peter,

    As hacker has said, the 32-5 has a 5-pin DIN plug (hence the '-5') which enables it to carry an extra 24v DC rail.

    So why don't you get hold of that 32 and mod it. If you find Neil McBride's Web-site, you can read about PS and other mods to Naim gear. I would agree with laverda - don't bother with a HiCap, make up some regulated PSes yourself and go one stage further than a "normal" 32-5/HiCap ... have a separate 24v DC rail for each PCB (ie. L & R gain stage, L & R buffer stage and L & R phono stage, if you have one. And get rid of the relay circuit! :) ).

    Then there are component swaps as well, to make it sound better! :)

    That will be a very nice preamp! :)

    I myself have a 110 for my "bedroom system" and it works well ... the only issue, I suggest, is whether it has enough juice (compared to a 160/180) to drive your Kans or LS3/5A adequately?


  7. mocenigo

    mocenigo pfm Member

    I knew that the Phono stage was on one rail and everything else on the other rail. Are you sure? I have to open my 32.5 and look inside carefully, then :)

  8. PlattenFantast

    PlattenFantast TT user

    Andy and Robert - THANKS for these very encouraging words!
    I have tried to access Neil McBride's web site for a while now, without success - is it down? http://www.neilmcbride.co.uk/
  9. hacker

    hacker Delicious and nutritious

    Definitely. This makes a tremendous difference to sound quality, taking the humble 32 way beyond its normal performance. I did this with my 62, using an off-board PSU with 4 seperate power rails feeding 4 ALWSRs inside the preamp and it was stonkingly good. If you need some advice on making this work for your 32, just ask - a few folks here have gone down this route.

    Indeed, but a word of caution here: changing components is easy, but not guaranteed to get you much more performance. I always think swapping caps and resistors changes the character of the amp's sound, but it's more of a sideways step than a step up. To this I'd add one caveat: the feedback capacitor is far better when you use a film cap, like an Evox MMK.

    A few of my favourite mods would be:

    - 4 independent ALWSR power rails with the 27R/47u RC filters removed

    - Linnik's Xmas mod. Do a search on the forum for it - it's tremendous.

    - Swapping the feedback cap for an MMK (47uF if using 1K resistor or 22uF if using a 2K - see the next item...)

    - Replacing the 1K feedback resistor with a 2K to reduce the gain to 6x

    An amp with those mods will sound sound amazing. As for Neil McBride's web pages, they're down now but you can still access them via the Way Back Machine (www.archive.org) by clicking this link: http://web.archive.org/web/20060402221029/http://neilmcbride.co.uk/

    Happy modding,
  10. mike_in_co

    mike_in_co pfm Member

    Another fairly important difference, even from a modder's perspective, is that the traces of the 32 main board were drawn by hand, and aren't uniform in their size and layout. The 32-5 was done on some sort of computer, and is much more consistent and organized. The power and ground layout in particular on the 32-5 are much better. As a result, if you run a 32 and a 32-5 each from a 4-pin SNAIC (ie 1 24v rail), the 32-5 will sound noticably better.

    Even if you snip jumpers and cut traces necessary to run split power to the different stages in a 32, (using ALWSR, or SMPS, or even just a HiCap), the ground layout will not be as ideal as a 32-5. It may not be a major difference for some, but I thought it worth noting.

    Finally, I should also note that I have a 32 with heavy mods and it sounds amazing to me, no complaints at all. Happy to share pix and experience if you need it.

  11. PlattenFantast

    PlattenFantast TT user


    I'll post any developments and progress.
  12. PlattenFantast

    PlattenFantast TT user

    Getting older... :(
    This morning, I remembered that I had written that I travelled down to Southampton, to have my 250 updated...it was Salisbury, and we also managed to get a nice tour of the fantastic Cathedral in that town.
    Also remembered that on the roof of the Naim factory they had rigged the most mosntrous FM aerial I ever saw - looked positively like a military installation (this and some listening tests, prompted me to some time later get the NAT02 which was what I could afford at the time (BTW; an excellent tuner and a major step up from my trusty old Creek (also quite good for the money)).
    Three erason I want the Naims back; 1.) They do sound very special and musical, 2) They are IMO, without a shadow of a doubt, the most aesthetically pleasing design that there ever was - such simplistic beauty, an architectural feel. They easily belong in design museums all over, 3) Well, ahrrm...getting older...looking back I guess.
  13. The Captain

    The Captain ~~~~~~~~~~

    If I were you and funds can stretch, a 72 (big grown up 32.5) are bargains now, and a 32.5 had for ~£150 a bargain too (I have one and modded is a stonker). You're spot-on re naim stuff, and interesting you are yearning back after a long spell awol to its simple designs and je-ne-sais-pas simple grippy musical making. Sense prevails Imo.
  14. mocenigo

    mocenigo pfm Member

    Today I reopened my 32.5 to replace the 321 boards set, and started following carefully the +24VE rail tracks. I was wrong. The relay and gain (321) are on one rail, everything else on the other rail, as said by others.

  15. PlattenFantast

    PlattenFantast TT user

    Thanks hacker, for the link to Neil McBride's site :)
    mike_in_co; would you say it's not worth pursuing a mod of my 32 and instead get a 32.5 as starting point?
  16. mike_in_co

    mike_in_co pfm Member

    Depends on the price, I guess.

    IMHO, a modded 32 is fantastic, I use it as my primary preamp and have no complaints or regrets with choosing it over a 32-5. (Mine has the SMPS mod Mr Tibbs began, search for posts here about it).

    If I had found an inexpensive 32-5, it would probably be better, but 32-5s seem to command a premium that makes them less of a good test/tweak project. I've seen 32s go for US$100-125. The cheapest 32-5 I've seen lately went for more than 2x that. I'm not sure you'd get 2x the improvement over a 32.

    If you're industrious, you can run new ground wiring to the separate stages inside a 32 and improve the performance, perhaps even beyond the 32-5. (I haven't done this).

    Whichever you get, be sure to remove the balance pot and replace it with decent resisitors, it makes a big improvement.

  17. martin clark

    martin clark pinko bodger

    Mr Tibbs kindly condensed this to a 'how-to' and it's posted on acoustica here, with links to the originating thread :)
  18. markzb

    markzb pfm Member

    Hi guys

    I have myself a "sleeved" 32 that i "dual railed" and had always wondered how it would compare to a genuine 32.5 with it's "factory" twin rails.

    The rare opportunity presented itself one fine evening when a guy here in kuala lumpur advertised he was looking for a hicap or snaps.

    So... it gave me the opportunity to compare both the preamp and my twin railed super regged snaps with his 32.5 and hicap.

    My 32, in addition to being twin railed, also had a pair of line stage cards that had LesW perform some "optimization" :)

    So i managed to do some mixing and matching that evening :rolleyes:

    The results of the evening for me were that there is very little sonic difference between a DIY twin railed 32 and a 32.5. I certainly would not lose any sleep over this and would happily choose either. To describe the difference, i would say that my 32 has just that slight extra "warmth" to the sound. One could say that if someone had a bright edgy system, the 32 would perhaps be the preferable choice. Note, i am talking "motherboard" choice here.... the same cards were swapped between boards to compare.

    What was the bigger diference that evening was the Avondaled line stage cards. I bought these revision 5? boards in standard Naim form from RichardH sometime back and sent them to Les.

    They were noticeably good...so much so he wanted to buy them from me there and then! I later struck a deal with him... i sell them to him for what they cost me and a tiny bit... plus i get to keep his old boards :)

    Later on, the Snaps went to him too :) The addition of these two components really "completed" his audio system and we both ended up really happy.

    I in turn was making way for the Starfish and Count "Traco-la" :p


  19. PlattenFantast

    PlattenFantast TT user

    Thanks again!!!:)
    I have now landed a 32/110 at a rock bottom price ;) so this will be my starting point for now.
    Exciting stuff you are sharing.
    BTW; the Starfish board is no longer availanble is it...any thoughts about maybe doing a batch of those in da future?
  20. neiljadman

    neiljadman Senior Member

    Is this R9 on the 321 board?

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