Naim Nait XS as a Preamp for tubed power amp?

I have a original Naim Nait XS (not the XS-2 or XS-3) that was recently recapped. Love it. The only other Naim product I own is the the latest Naim CD 5si, which is also excellent.

My elderly uncle has an Assemblage ST-40 Power Amplifier that he wants to give me. He seems to think I can use my Nait XS as a preamp for it. The ST-40 is a tubed amp one makes from a kit that puts out 40-50 watts per channel (my Naim Nait XS puts out 60, as many of you know). I assume that I would be unable to use the Nait XS as a preamp, but wanted to be sure. All I want to know is if it is even possible so I know what to tell him. Either way, I will probably take it from him and hold onto it, in case I ever get a chance to have a tubed preamp separate I can pair it with.

I use a later model XS Nait; sure can be a preamp; I believe it turns off power to the power amp section when doing so… (not verified; but ‘yes’ it’s a good preamp…)

When used as a preamp, the (internal) power supply for the Nait XS is in overkill mode qnd likely leads to SQ inprovements.

Whilst I personally believe Naim achieve a ‘tube-like’ sound (using solid state architecture); the improvements to running a fully tubed power amp stage should be AMAZING… (but more costly in terms of ongoing costs(power and tubes))…

I retired my valve mono blocks and enjoy Naim cost savings.

The missus can tell we have had a sound quality decrease vs tube power amps, vut the Naim ‘house sound’ clawed back most of the difference.

I’d certainly encourage the project and also to ignore Watts numbers- they barely tell half the story as to what (pun intended) is important for musical material playback.

many like tube sound as it makes certain misoc genres really nice to listen to.

for me it ie vocals and certain instruments… but also the notion of ‘true power’ and a more natural audio delivery…


The power amp section is always “on” and powers the preamp section via the link plug. The only way of getting at the preamp output socket is to ; use a flatcap or hicap, and run off the ‘cap output socket, or use the sub out sockets on the back of the xs. Disconnecting the link plug will remove power from the preamp.


Thanks for letting me know! My Uncle and brother have tube systems and they do sound amazing, so I will have to see how the set up sounds in my room when we get around to it in a couple of months.

1 Like

Your uncle and brother have obviously had success in matching tubes with their speakers and their rooms. The key thing is surely how the tube power amp suggested matches your Harbeth speakers.

Hope it turns out for you, either way.

(If you don’t have a manual for your Nait XS, Naim’s suggested combo for an XS owner who wanted to add a power amp was Nait XS as a preamp, Hicap and NAP200. But you may know this already.)

1 Like