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Naim Pre Amps

m3trackboy

m3trackboy

pfm Member
Is the signal path's of Naim Nac 32, 62, 92 202, 252 the same? The circuits I have seen seem to be Gain boards, Buffer boards and Time aligned filters. The main difference seems in earth layout on the pcb, mechanical isolation and chassis design and I presume much higher quality components.
 
I'm a bit surprised that nobody has jumped in on this, given the knowledgeable crew we have on pfm. My understanding is that NAC12,22,32,42,62 are all very similar and I recall Julian Vereker mentioning the fact that it was basically pot luck which one would sound better as it came off the line.
 
I probably should trawl through the forum I'm sure this has been done to death!!
The system I have in my head (and partly built) is a pair of NCC200's, a pair of mini cap 6's and 35-0-35 AST tordial, this is nearly finished.
For a preamp I have bought a NAC 92 with the idea of just using the case switching and DIN sockets but drop a 152 flea-bay board in which I would build using good quality parts. This would be powered from a separate power supply and gyrators on the separate stages. I only need cd input and maybe one other for a lp12 not fussed about remote.
This would then feed SBL mk2's. Room is about 20' x 12' solid walls but a wooden floor on screed.
The above should give me a reasonable sound. I've just striped the 92 down and it seems to be the same circuitry as other NAIM preamps without the time aligned filter, how much sonic difference does it make?
 
Well, I think I'm right in saying that the 72 was one of the first to use the TAF, but it was never one of my favourite Naim Pre-amps, though having said that, I'm rather fond of the 102 that I'm using now. Sounds like you have the makings of a fine system BTW.
 
Or build a Preamp based on a pair of LesW 821A boards
Dual output 22V transformer with rectification and smoothing on the output to 2 positive supplies 32VDc
TPR4 for regulation 2 x 24V supply.
Add as many inputs and outputs you require, use an Elma 6 way switch for the inputs, if you only need a couple LesW has a board with relay switching.
Fit a volume pot or stepped attenuator of your choice, I use a 25K Goldpoint stepped attenuator

Alan
 
Just curious. If you build your own Naim copy pre then are you supposed to abide by the same legislation in place today or can you copy what Julian designed to the letter? If it’s for personal use at home then I’m assuming you can do what you want...

Also, do the parts even exist today to get close to a 70s NAC? Or maybe some parts today are better...?
 
I've got loads of those left. Just used my last pair of les's minicap boards in the current Paradise build I'm doing though.

I'm thinking of doing four bib ultra shunts to power my own Paradise, just for laughs.
 
Bob McC said:
I wouldn’t presume higher quality components
Click to expand...

Indeed, the components used are pretty much identical across all the Naim amps listed.

——-

I tried reducing the gain of the pre-amp a number of times and didn’t like the result at all - at least not into Naim power amps (I didn’t try it with any others).
 
To answer the OPs question, in the case of the 32 and 62, yes, they both used the same 321 and 324 circuits with identical component values. The 92 used the Nait3 preamp board which may have used simplified versions of either or both circuits - (I'll update this if I go through my NAIT 3 files). The 202 and 252 are the new casework versions of the Olive series 102 and 52, and would have used the 729 style TA input buffer in place of the 324 buffer; see discussion below.

There were some subtle component value changes to the 321 gain circuits between the 42/32/62 and 72 which are listed on the Acoustica site.

Also in moving from the 72 to 102 to 82 there were some component values changed to the input buffer (TA or 729) circuits. Interestingly the values in the 72 were the same as the 82 but the 102 used different values (cynically some might say in a deliberate downgrade/compromise to create the upgrade path). IMHO the 102 certainly benefits from the values being changed back to the 72 spec -along with a few other mods of course!

The main difference between the 102, 82 and 52 is actually in the number or power rails that can be used - see my posting for 102 mods for more details: https://drive.google.com/file/d/0ByAeclGjRjLUQjZEa0d4U3hhVGM/view?usp=sharing

But right through to the 52, the components used were the very same except for those Samwha electrolytics replacing the ROEs, which I think happened with the 102, though this might only have been on later years.

Now I have never pulled apart a 555, but I have heard that the tantalum signal coupling caps made way for Wima MKS2 film caps, can anyone confirm that? And I do know that one of the resistors in a critical position in the 555 preamp was tightly measured, sorted and matched to a specific value - I have an ex NANA tech's set of bench repair components and one of the drawers is labelled to that effect.
 
neiljadman said:
To answer the OPs question, in the case of the 32 and 62, yes, they both used the same 321 and 324 circuits with identical component values. The 102 used them too, but being so much later I have no idea of the 321 circuit upgrades used in the 72 were incorporated, I strongly suspect not. The 202 and 252 are the new casework versions of the Olive series 102 and 52, and would have used the 729 style TA input buffer in place of the 324 buffer; see discussion below.

There were some subtle component value changes to the 321 gain circuits between the 42/32/62 and 72 which are listed on the Acoustica site.

Also in moving from the 72 to 102 to 82 there were some component values changed to the input buffer (TA or 729) circuits. Interestingly the values in the 72 were the same as the 82 but the 102 used different values (cynically some might say a deliberate downgrade/compromise to create the upgrade path). IMHO the 102 certainly benefits from the values being changed back to the 72 spec -along with a few other mods of course!

The main difference between the 102, 82 and 52 is actually in the number or power rails that can be used - see my posting for 102 mods for more details: https://drive.google.com/file/d/0ByAeclGjRjLUQjZEa0d4U3hhVGM/view?usp=sharing

But right through to the 52, the components used were the very same except for those Samwha electrolytics replacing the ROEs, which I think happened with the 102, though this might only have been on later years.

Now I have never pulled apart a 555, but I have heard that the tantalum signal coupling caps made way for Wima MKS2 film caps, can anyone confirm that? And I do know that one of the resistors in a critical position in the 555 preamp was tightly measured and sorted to a specific value - I have an ex NANA tech's set of bench repair components and one of the drawers is labelled to that effect.
Click to expand...

Slightly off topic... but I'm curious! One reads of "chrome bumper", "olive" etc but I don't recall seeing a variety of different topologies etc... people say "ah what you need is the olive era one" etc/whatever... call me a cynic... but are they basically all the same apart from restyled casework? Are any differences just a few resistor value changes as you mention re specific pre amp models as above?
 
Yup, chrome bumper is pre 72 model. They just started spraying the ends of the cases and used plastic front panels in the Olive stuff. I obviously they improved stuff as they went along but they're more similar than dissimilar
 
sq225917 said:
Yup, chrome bumper is pre 72 model. They just started spraying the ends of the cases and used plastic front panels in the Olive stuff. I obviously they improved stuff as they went along but they're more similar than dissimilar
Click to expand...
I think it was the other way round - in the "Chrome Bumper" era, the powder coating was milled off of what became the front end. And they just left it there in the olive series.
 
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