Phono boards,

[GrumpyOLDvinylJUNKY]

I’ve just upgraded to a 42.5 with MC boards,
My turntable is MM
QUESTION
Can I take the MM boards out off my nac92r olive
And fit them into the 42.5?
Thanks

[Richard.Dane]

No the NAC42.5 uses NA3xx boards, whereas the NAC92R uses NA5xx boards. They mount differently to the main board and are not cross compatible.

[GrumpyOLDvinylJUNKY]

Is there any where selling these new,
I take it xx is any number after the 3?
Thanks gareth

[Richard.Dane]

They have been out of production for at least a decade or more. Try some Naim dealers or else keep an eye on the usual sales places.

More info on the daughter boards can be found here in the forum FAQ;

Naim NA3xx and NA5xx Pre-amplifier daughter boards

Earlier Naim pre-amplifiers used interchangeable daughter boards. While the very earliest NAC12s did not use daughter boards, most were updated, and the early versions of the NAC12 and NAC22 used NA1xx and NA2xx boards that used knife edge connectors but were superseded by pin mounted NA3xx boards. The NA3xx boards that can be found and used in later NAC12s are; NA325 - Switching Relay, switch-on output delay x 1 NA321 - Main gain, output drive x 2 NA324 - Input Buffers x 2 NA322 - MM …

[GrumpyOLDvinylJUNKY]

Thanks for that, I’ll find a pair,
And i can sell my mc boards to pay for them,
Can I ask why you put xx thanks

[IanRobertM]

@GrumpyOLDvinylJUNKY

Can I ask why you put xx thanks

NA 322 N or NA323 S/K/E

NA 522 N or NA523 S/K/E

All of these boards can be found with diligent searching and a bit of patience.

Its possible to convert between S, K or E. Its not possible to convert from N.

[GrumpyOLDvinylJUNKY]

Found these but don’t know what type they are, thanks

[Richard.Dane]

If you turn them over it should say on the PCB.

They appear to be NA322 boards. The other side should let you know the issue number (1-4). They would likely benefit from a service.

[GrumpyOLDvinylJUNKY]

I thought they might be, no markings on other side, i looked at pictures internet and came to the conclusion,
But needed a Expert to be sure,
Defo going get a service,
Before it goes in,
Going to get my passive cross overs done at same time,
(Just got a set of nice SBLs)
Thanks for your help, again,
I’m sure I will be back

[Bassman53]

The ”dreaded” Roeder caps…
Had them in my Mission Cyrus amp also.
Plastic cover on them that cracked.

[JohnDoc]

I’m plugging a MM cartridge into my 42.5 but the volume is very low, would that indicate the the boards are for MC? I’ll open it up and take a look for any labels.

[Richard.Dane]

An MM cartridge into MC boards would either be very loud or just distorted, as the output of an MM is much higher than an MC, and the gain of MC boards is much higher than MM.

It could indicate though that you have line level boards fitted.

[JohnDoc]

Thanks Richard, it looks like line cards, NA 326/1 are fitted, the units came with a Nakamichi tape player which I know was supplied with them from new, looks like there wasn’t any intention of playing records. I’ll have a look round for some MM boards.