Can someone in the know tell me what the output level is for the XLR outputs on the HE?
I am looking to use the Atom with a power amplifier with balanced inputs with a gain set to 4V for maximum output.
I have a sneaking suspicion the Naim have set the XLR outs at 1V. My current amp has about 26dB of gain and the amp driving 4R Buccardt S400’s I typically listen at around volume at 45 so I have leeway but I’m not sure how far I’ll have to crank up the volume with 6dB less of input sensitivity.
One thought I did have was connect to the XLR headphone out at the back. I wonder how that would work. The class A amplifier should provide good fidelity and also have a nice low output impedance which has to be a good thing.
I know one forum member uses his Atom with a March Audio Purifi which I know has a 4V input.
People using the XLR outs I’d be grateful to hear their experiences.
Hi @OzBrit
Not entirely sure if this helps, but I use an LSA Warp One power amplifier with my Atom HE and this is what I read in one of the reviews:
The TPA3255 amp has an intrinsic 22dB of gain, so the setting from the factory is 6dB for an overall 28dB gain**.**
In my case I never experience the Atom HE gain to be too little or too high with this power amplifier.
I hope this helps.
Edit: you might find what you are looking for in this Hifi News Atom HE test report with measurements: https://www.hifinews.com/content/naim-audio-uniti-atom-headphone-edition-streamerheadphone-amp-lab-report
BR,
Richard
Hi Richard
Thanks for the reply
Looking at that review it looks like the output at 100 volume is 4.75V so technically I should be ok. I also note that the the XLR headphone out also has an extra 12dB of gain so theoretically that could also be used as a pre out although I think that output is always on even when the line outs are on (so I’ve read not tested this). The only way to find out is to try both and see how they sound.
Did I read in an earlier post that you tried the Purifi amplifier or was that someone else. If so how did you find it?
I think I am going to build the Starkrimson Ultra amplifier to partner with the Atom so another class D amplifier. Normally all my builds are in the class AB arena so this will be a first. I’m always curious to find out how others are finding class D amplifiers?
I did try the Purifi EVAL1 indeed. And nCore 400 and a Naim NAC200. But the LSA Warp One is my end station for now. It simply sounds superb with my Dynaudio speakers. Where the nCore and Purifi sounded ‘class D’, I don’t even notice anymore that the LSA is a class D design. Sounds as good as a class AB design to me, but with the advantages of class D: low power consumption and does not get warm, so I have it in a cabinet where it does not get warm. The network switch gets warmer. 
Edit: a bit more on how I experienced the differences between the power amps.
First of all: the Atom HE is an absolutely stunning preamp. Small size, lots of features and a dream to use.
The nCore 400 with SMPS1200 power supply were mono blocks I built myself. They sounded very dynamic, but the highs were not as smooth as I would have liked.
When the Purifi became available I decided to build a stereo version, again with the SMPS1200 power supply. The Purifi sounded smoother in the highs, was more quiet and as dynamic as the nCore. I really liked it and I could have lived with it for years. A friend of mine still uses a Purifi to power his Klipschhorns and those sound superb.
But when the LSA Warp One was launched, many reviewers stated that it was the first class D amp they heard without the ‘edgy’ highs that the nCore had and to a lesser extent the Purifi as well. So I took the plunge and ordered one. I had to order it from the US and ship it to The Netherlands, so could not listen to it before ordering. But luckily it turned out to be a bulls-eye in my setup.
Some reviewers also mentioned the strong musicality and PRaT of the LSA, which made me think it would partner very well with the Atom HE. And that turned out to be the case.
BR,
Richard
Hi Richard
I must admit I have looked at the Purifi several times and nearly bought a pair. But I was always put off by the people who needed to swap the buffer boards to get the sound they wanted. Reviewers said it needed pairing with a valve pre to get a similar sound to class AB etc etc. That didn’t sit well with me even though I know the Atom is ‘full’ sounding which would probably help if I paired with a purify amp.
I have been taken by the Orchard Audio Gallium Arsenide based class D modules which are getting some rave reviews even from some who normally sit in the valve camp. A friend has just built some up and is giving them high praise so I’m going to take the plunge and order some.
Re the Atom HE yes I agree it’s a great pre streamer dac headphone amp. It’s capable of superb sound quality and I agree the HE version is better than the pre outs on the standard Atom (which I still own incidentally). My only gripe with the Atom is its susceptibility to poor quality mains which unfortunately plagues me in my house. There are periods where a gritty distortion creeps in and the sound just falls apart. I’ve tried many mains filters, an iFi Purifier and am about to order a balanced mains transformer. If that fails then a mains regenerator will be required. Here in Oz they cost more than the Atom but I will try building mown using an inverter and battery solution. Fun and games eh!
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Totally recognise what you write. I first owned the Atom and then changed to the HE as I felt it was silly to not use the power amplifier section. Both sounded excellent as a preamp, but the HE is more versatile in the end.
For power conditioning I ended up with an Audioquest Niagara 1200 with Monsoon cables. It sounds superb and more stable now, regardless the time of day.
Good luck with fixing the power issues!