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Difference between Naim 323 and 523 phono boards

Richard Lines

pfm Member
Good Evening All,

I've tried doing a search and can't see any obvious answer to my query - what is the difference between the 323 and 523 series phono boards?

Looking at pictures on the inter web the 3 series generally seem to have 11 transistors and the 5 series only 9 but I suspect there is much more to it than that.

Regards

Richard
 
323 fit NACs 32/32.5/42/42.5/62/72

523 fit NACs 102/82/52

There are also S and K versions and several revisions.
 
Good Evening All (again),

At least nobody has, yet at least, pointed out that the 3 series stick up and the 5 series lay flat!!!

I have only seen the schematic for the 323 and never, to my knowledge, the 523.

I think my counting might be wrong as well as the 3 series have 13 transistors in total?

Regards

Richard
 
...and the 5 series are 'handed' whilst the 3 series are not.
 
But the circuit is identical on both (bar a resistor value change on the 323's from v4 onwards) ie no difference in sound whatsoever!
 
But the circuit is identical on both (bar a resistor value change on the 323's from v4 onwards) ie no difference in sound whatsoever!

But looking at assorted pictures on the inter web/ eBay etc. they don't all have the same no. of transistors fitted so I would, politely of course, challenge the assertion that all the boards are 'identical'. Thus my question.

Regards

Richard
 
But the circuit is identical on both (bar a resistor value change on the 323's from v4 onwards) ie no difference in sound whatsoever!

Different in the PCB, layout, ground planes etc surely?

5s came in with the 52 I believe, the 3s are as old as the hills but went through some variations on the way, I assume they would still plug in a 12 though I started with a 72 (and ended!) so i may be wrong on that :)

Prefix is effectively the 5s on one PCB, I assume Stageline ditto, I'm sure others can confirm.

Not sure I am helping but my point is the same circuit can be made on different PCBs on different layouts and have different SNR, cross talk, etc, etc, etc. Do you hear that difference, depends, I suspect you can under some circumstances at least.
 
I've had all options, the best sounding was the Prefix. Easily beaten by outboard stages though. (Trichord/Arkless/DV P75 ect)
 
Yes they do!

13 on either sort as standard.
\
I must have been hallucinating me thinks as I now can't find the one picture to make my point and all the ones I can reinforce yours - I think I'll go and crawl back in my hole........

Actually time to get back up on the Bridge as we approach the new anchoring location for the rig what this here boat is towing.

This is all about buying a second set of boards for modifying (in case you hadn't all worked that out for yourselves). It may not happen anyway as it won't work with the Urika II.....

Regards

Richard
 
I've had all options, the best sounding was the Prefix. Easily beaten by outboard stages though. (Trichord/Arkless/DV P75 ect)
I think I agree, while i haven't tried them all I have original 3s in a 72, prefix, and recent tried the RSL phono stage. The 3s do have that cohesive Naim sound, prefix is all that a a bit more while much quieter, I assume the 5s are between the 3s and the prefix, while the RSL had more detail, soundstage, and was tighter. Though that gives up the Naim sound a little, I would say it is as much that greater insight and detail by it's nature reveals the cohesive Naim sound to be blurring over the finer points. You pays your money and takes your choice.
 
The layout certainly differs between versions, but having had quite a few variants I can honestly say that I never actually "heard" any difference between versions.
 
Do these 323 boards require servicing after a few years of use? I had the ones in my 72 repaired with non Naim components about ten years ago.
Also would it be worthwhile restoring them to their original "Naim-iness"? They are the 323/S boards for a still functioning Supex cartridge/Grace/LP12.
This still sounds ok but I need to crank the volume by a third from CD listening levels and even then it all seems to run out of steam where a CD at that volume setting would pin me to the wall!
(Apologies for slight off topicness but advice/abuse/pity would be welcome. :)

Kendo
 
Do these 323 boards require servicing after a few years of use? I had the ones in my 72 repaired with non Naim components about ten years ago.
Also would it be worthwhile restoring them to their original "Naim-iness"? They are the 323/S boards for a still functioning Supex cartridge/Grace/LP12.
This still sounds ok but I need to crank the volume by a third from CD listening levels and even then it all seems to run out of steam where a CD at that volume setting would pin me to the wall!
(Apologies for slight off topicness but advice/abuse/pity would be welcome. :)

Kendo
I guess it depends who repaired it as to whether it is worth getting them reverted to original and what they had to replace/repair! Hard to just "know".

No they don't need servicing every 10 years I would say. Even if you left the preamp on 24/7 it is stuff that gets hot and carries power (simplistically) that needs the service every 10 years. These do neither really. Probably never is just fine.

You don't get the same output levels from a set of phono cards in a Naim amp as a typical high output line level from a CDP. You can either drop the CDP level using attenuated cables to match phono or get an external phono stage with more/adjustable gain or lump it. I do the later. But then I don't swap between CDP and phono much.

Though if you say you just can't go loud enough on phono, perhaps the repairs have left you with less gain than they should have? What is the rest of the system? I may have to turn it up to 11 but I can rock the house on 323s quite happily.
 
Line level inputs on most Naim pre-amps are very sensitive, hence relatively little usable range with CD, IME. However, you should still easily get significant levels with vinyl (at higher positions on the volume control, relative to CD), assuming a suitable match between cartridge and phono boards.
 


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