Blimey....

Blimey Graeme, going from a bare 272 to one with a 555 up its bottom is going to be a blast.

Keep us informed, but as you have called your thread the 'B' word, don't be surprised if the conversation strays a little!

I am just listening to the late, great Leonard Cohen Popular Problems album and it is just stunning with a 555 in the mix.

I'm interested to hear how this trial goes as I have difficulty getting my head around investing in a 555 psu that is around twice the price of the 272. No doubt it makes an amazing difference, but I'd still find it hard to justify spending that kind of money. I might consider it seriously if I was in the audio-perfection territory of an NDS/Statement Naim user. But I'm not, and for now the XPS-DR is good, indeed very good for me.

Atherton posted:

I'm interested to hear how this trial goes as I have difficulty getting my head around investing in a 555 psu that is around twice the price of the 272. No doubt it makes an amazing difference, but I'd still find it hard to justify spending that kind of money. I might consider it seriously if I was in the audio-perfection territory of an NDS/Statement Naim user. But I'm not, and for now the XPS-DR is good, indeed very good for me.

Well there's always a VFM judgement to be made - I've said the same about expensive wires -but if you're looking to optimise around a streamer/pre then it makes sense.    

Regards,

Lindsay

Atherton posted:

I'm interested to hear how this trial goes as I have difficulty getting my head around investing in a 555 psu that is around twice the price of the 272. No doubt it makes an amazing difference, but I'd still find it hard to justify spending that kind of money. I might consider it seriously if I was in the audio-perfection territory of an NDS/Statement Naim user. But I'm not, and for now the XPS-DR is good, indeed very good for me.

I share your cost angst Atherton. Experience of adding an XPS or 555PS to CDS2/3, HDX, NDX & Ndac has shown me that the 555PS is really the appreciable jump. I hung out for a S/H (non-DR) one on this occasion. I know if I’d gone to an XPS, even ‘DR’, I’d always have that nagging feeling of wanting to hear the next step up.

Might hook it up tonight.

G

The idea of a £6,000+ power supply on a £3,500 streaming preamp is certainly odd, but the 555 is rather special. Mine’s been running in for a few weeks now. I just sat down with a beer and put on a Joshua Redman album I’d not heard for a while, and it was just incredible. So different to before, so real, so captivating. Of course there is the issue of it running in together with a new power amp and new wires, but what can one say, other than ‘blimey’?

Clive B posted:

It's curious that the 555 unit unpacked appears so heavy, yet when it's packed in its box it doesn't feel so bad. I guess it's about anticipated density. 

Anyway, enjoy the monster power supply. Blimey indeed!

I thought that about boxed vs unboxed too! This is my third 555PS so I should be used to that by now.

It’s absolutely minty, just one owner.

G

Hungryhalibut posted:

The idea of a £6,000+ power supply on a £3,500 streaming preamp is certainly odd, but the 555 is rather special. 

I agree, but I prefer to think of it as a choice between a £3.5k streaming pre-amp and a near £10k streaming pre-amp.  That's the way I think about my nDAC. Some manufacturers offer different models at different prices and the only difference on the dearer one is the upgraded power supply. Credit to Naim for transparency and offering the choices.    

Blimey, I am still in shock (and a little confused) by the difference a top notch power supply can make. As someone has already pointed out, no musical signal actually passes through its circuitry so how/why does a power supply have such a profound effect on the final SQ?

To be honest we have been told for years to invest in the power supplies in our Naim systems and the how and why don't really matter. The fact that a PS has this wonderful impact is all we really need to know. It also goes a long way to 'justify' the huge cost of what is a glorified transformer.

There I go, showing my ignorance again. 

nigelb posted:

Blimey, I am still in shock (and a little confused) by the difference a top notch power supply can make. As someone has already pointed out, no musical signal actually passes through its circuitry so how/why does a power supply have such a profound effect on the final SQ?

To be honest we have been told for years to invest in the power supplies in our Naim systems and the how and why don't really matter. The fact that a PS has this wonderful impact is all we really need to know. It also goes a long way to 'justify' the huge cost of what is a glorified transformer.

There I go, showing my ignorance again. 

From what I understand of Naim amps, a simplified way to look at a power supply is that it provides the energy required by the circuit it supplies to produce its output, which in the case of an audio circuit is an amplified version of the input signal. Audio signals are alternating at the wide range of frequencies that the music is composed of. Ultimately the loudspeaker converts the electrical energy into sound wave energy. So just as the sound energy is constantly varying so is the electrical energy being drawn from the power supply.

The capacitors of the power supply provide a reserve which is topped up. Apart from the smoothing effect of the capacitors, energy is being supplied by the mains at the rate it is being output by the speakers and the heat generated by the electrical components. This is just conservation of energy. It is wrong to think that the power supply is not experiencing the audio signals: it is - it just that it’s not doing so actively. 

According to Jason on my recent factory tour the Statement can go from zero to 9000 watts in a picosecond. Obviously this only lasts for microseconds. When a power supply cannot provide the energy required by an audio circuit, the output current of the audio circuit will be less than that required for the circuit to behave linearly.The signal is then being distorted.

A SuperCap is used by the 282 and the 252. The 252 uses a Burndy which allows the circuits to be supplied independently from the PS. This probably means that the individual circuits are ‘quieter’. What I’m not quite sure of is whether each output of the SuperCap has its own secondary tapping.

Hope this makes a bit of sense. I’m only a physicist by education rather than an audio engineer. Just trying to give a simplied view.

Phil

 

I’m a bit concerned about some of the claims said to have been made by Naim staff during factory visits.

Last week there was the assertion that a Statement system consumes £600 worth of electricity quiescent consumption if left on. Ignoring the fact that the existence of a standby mode using only about £1 PA had been overlooked, by my calcs based on a typical electricity cost of 13p/unit in the UK, a stereo Statement system according to published specs would only consume about half the declared amount - so either the claim was wrong or the published specs are wrong.

Now this claim of 9000W/pS. Expressed in typical units for amplifier measurement, this equates to 268 000 000V/μS (or in different terms, power can rise from zero to 9000W in 1/50 000 000th of one cycle of the highest frequency sound a human can hear - indeed, that would be superlative performance in a microwave transmitter amp!). That is an incredible rise time, and whilst I am not in a position to say it is not posssible, I do have to wonder if the unit# may hav3 got mixd up somewhere...

I do think that if there are exaggerations being made by Naim staff, or mishearings by visitors, they should be addressed in order not to mislead, in either direction - and should my scepticism regarding the slew rate be unjustified I wholeheartedly apologise. Perhaps Naim could step in here for the record on these points. ( @Phil Harris 

I suspect the analogy here is with a car, any car. The PSU is the car engine. Swap the engine out for a more powerful one and the car handles differently. Exactly how differently will also depend on how well the suspension and brakes etc are set up on the base model. I also suspect that this is partly the reason why some PSUs sound "overblown" when used on some amps as staying with the same analogy, on those amps the suspension and brakes set up can't handle the extra power.

Pushing this analogy as far as I can, then the base 272 is a Golf GTI with the engine replaced by a 1600cc unit, still a nice car but not very dynamic. Put the GTI engine back in and it is obviously much better. It works in both situations because the brakes, suspension and steering are all top notch.

Duck for cover now....

Mike

Mike1960 posted:

The PSU is the car engine. Swap the engine out for a more powerful one and the car handles differently. Exactly how differently will also depend on how well the suspension and brakes etc are set up on the base model. I also suspect that this is partly the reason why some PSUs sound "overblown" when used on some amps as staying with the same analogy, on those amps the suspension and brakes set up can't handle the extra.

Yeah, a HCDR on my SN2's pre steered me into a ditch. Thankfully I found a good tow truck and I'm now back on the road. Moral of the story: PSUs may not be fit for lesser drivers and use your car analogies sparingly.

Innocent Bystander posted:
DynFan160 posted:

Blimey is not a word in the American dictionary...

I’t is a call to be blinded.

SO - the Gro'cers A'postro'phe has became self-aware and turned against its creator's.

'!

The remaining hope for humanity was that , like time on a stopped clock, it would occasionally stumble into the correct position.

Paradoxically, those who are bewildered by them retain just enough knowledge to get things consistently wrong.

Bob the Builder posted:

And what in god's name is a picosecond? 

It’s a millionth of a microsecond, a millionth of a millionth of a second... it’s fast. When I was young, it was faster than fast: picosecond laser pulses were just over the horizon. Now, it’s a million times slower than the new fast... it’s a million attoseconds, and an attosecond is about the shortest timescale we can access experimentally with really really fast lasers. The poster who challenged the validity of the assertion about kilovolt per picosecond risetimes in conventional electronics, such as the Statement, had good reason imho... A picosecond is a really short time... Blimey doesn’t begin to describe it!

Regards alan

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