I’m guessing his CD player volume knob was in the analogue domain … so actually he was under a misapprehension that he was avoiding a preamp stage … in reality just using a crappy onboard one instead … so no wonder yours sounded better. Using an onboard digital volume system … dCS, Wadia et al … is a different argument. Not saying better or worse, but worthy of discussion for sure.
This is what I’m interested in, and why I posed the question…I used the S1 as a reference because it’s an enormous, expensive and complex pre
I wonder why Martin Colloms , Naim lover, likes so much his Allegri. He reviews a lot of Naim stuff in Hificritic, but still has no Naim pre.
However the Allegri reference costs 3 times vs the Allegri. Should be interesting to know how it compares vs a 552 or 252.
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Big can be beautiful TT. 
ATB Peter
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I have personal experience designing amplifiers, so have reason for some input into this…
If a power amp is going to work well with a passive preamp, some specific considerations need to be taken into account, these include:
Input impedance
Closed loop bandwidth
Open loop bandwidth (i.e. “internal compensation”)
Out of band response
Transient out of band response
Closed loop gain
Open loop gain and ratio to the closed loop gain
Transient overload response at the input
Transient overload response after the gain stage (particularly avoiding driver latch up)
If these aren’t taken into account, the power amp will never perform so well without a preamp that conditions the signal ready for the power amp. If a power amp is designed for use without a conditioning preamp, it will be compromised for use with a conditioning preamp!
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Look at Soulution brand for instance or Chord. They make dacs with inbuilt volume control, to be connected directly to an amp, and they make true analog preamps too.
So what to say of their power amps, for what are they designed to be used for?
This quote gives a bit help to understand the use and need for technology superior to just match some buffer driven output signal with the power amps input stage
Apart from that , some of the things discussed are really in need for much better technical understanding, eg why a discrete regulator does what it does in that area of the cirquit
All I can honestly claim is, that I have worked with some of the greatest passive volume and or buffer designs and they all got beaten in parameters such as clearity detail, punch and over all definition. And the reason has a lot to do with how perfect the parameters of a signal the power amps input stage gets fes with - I tried ti point out - never is a simple pssive stage “neutral” it just creates that the electrical properties of the signal source get passed on in a way, the power amps input stage can electrically not achieve to reproduce the fullest quality of the musical content/signal with
Source of the quote below I cannot post but its from the very informative audiobeat review
The company’s well-publicized reservations over the matching of output devices drove them to an extreme solution. Increased power output inevitably meant increasing the number of devices, so working with the supplier who already produces the proprietary output transistors used in the NAP 500 DR, Naim created a new high-capacity output device in which individual sets of output transistors are cut from adjacent positions on the silicon substrate, individually paired and numbered so that they stay together from production to final installation. The power amplifier runs a class-A voltage gain stage followed by a class-AB current gain stage, the split topology allowing isolation of the delicate voltage amplifier from the loudspeaker load. There’s no global feedback around the two stages, allowing the amplifier to be very fast.
Naim also developed a new discrete regulator (DR) circuit that can be placed immediately adjacent to and trimmed precisely to match each individual device in the output and driver stages. Discrete regulators are not exactly new, while close coupling them to the devices they feed is the sole raison d’etre for the layered air-dielectric construction employed in the Connoisseur preamp and phono stage, but regulated power supplies have always been big in the Naim philosophy, and if you are going to follow (or extend) an established path, make sure it’s a good one! You might wonder just how significant using adjacent slivers of silicon can be (a subject to which I’ll return later), but there’s no doubting that well-executed power-supply regulation has a huge impact on sound quality, while one sage old designer once pronounced that “The volume control is 80% of the sound of a preamp.”
They may be designing the outputs of they DACs to, in a limited way, behave as a signal conditioning preamp, or they may be only partially doing this so as not to seriously compromise the performance into their own power amps while still ensuring that there is an appreciable gain when using a separate preamp to complete the signal conditioning.
Or…
They could be specifically deigning their power amps to make some partial allowance for the less well conditioned signal from their DACs, providing room to get better matched signal conditioning by inserting their own pre amps.
It’s all a choice of engineering compromise and where you do the signal conditioning.
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That’s just normal practice
That doesn’t follow from that, however that isolation DOES follow from the next point…
That may be a factor involved in the amp’s slew rate, but it’s just one factor among many.
I’ve never heard the Allegri, but I’m curious about it. Like you, I used a 72 while my 552 was away. I was expecting a sonic cold bath followed by maybe a week or two of grudging adjustment, but I liked the loaner so much that I bought it (it’s still in its box, fate uncertain). “Slightly grubby, and bursting with musicality” is an excellent description. I think the 72 is one of the best products Naim ever made.
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I’ve had my 72 for over 30 years, along with my 135’s. Always handy for when things need to go to the factory and always surprising when inserted in the system.
You seem to have similar taste to me as the other item in my standby collection is an old Creek 4140 tuner. Sadly, with the slow demise of FM, and the attraction of streaming stations like Radio Paradise, it sits in my garage gathering dust!
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In terms of hours per day, my Creek tuner is far and away my most used source component, mostly for background listening. An unexpected benefit of the 552 is how kind it is to lesser sources.
I was curious too, and tempted by reports that it performed well in a 500 system. I figured if someone was prepared to use it as a substitute for a 552 it would surely be able to perform well enough in place of my 282, allowing me to replace 3 boxes with 1 small one with no power cord. Sadly I just couldn’t get it to sound any good, despite trying it in a couple of different systems with a variety of cables, so I sold it and moved on.
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Was my experience too. I thought it sounded dull and actually a little ‘tinny’ in lieu of a 282 when I began to Naim swap. Was surprised given reviews. The little Schiit passive I tried was far more to my likening and about 5% of the price. Perhaps it was the colouration of cheaper equipment I preferred…!
I used a passion passive pre amp into VTL power amps and it was fantastic…I think the valve amps were somehow much more tolerant to the passive attenuation. So they can…work. I have heard a Nap 300 driven direct by a Dave and it sounded squashed and undynamic.
As You pointed out …. Correct
The quotes You picked are from the audiobeat article’s author and understanding of the technical topology
Maybe this is a good candidate as part of the FAQ or a sticky thread.
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I agree completely about how the 552 encourages the best from worthy, if not superlative, sources.
So enamoured was I of the results from my Creek tuner through my 552 system that I asked a friend in Naim Service to fit a replacement DIN socket to the circuit board - suitable for use with a HiLine.
A remarkable uplift - speaking to the underlying, if mildly throttled, quality of the Creek.
I also found the CD555 equally benign with pre-digital recordings transferred to CD.
The music of my youth - Animals, Burt Bacharach, Kinks, Dusty Springfield, Elvis and so on. None of these had sounded at all correct (possibly - familiar) during the early days of CD player development but here, with the 555, the exact same discs took on an old life.
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Hi Adam,
I hope you are keeping well.
Stop egging us on about the 552 
which I have managed to apply some self discipline and stay with my lovely 252 plus 300. After a brief period of the dark side with mains conditioners I am finally very happy without any of these devices that did not work at all. I still listen occasionally to the Pierre Bensusan. So thanks for that.
Oh and no 555 here just a mere cds3 and xps2
What we’re your findings with mains conditioners???