Try it - if it sounds better use it that way usually works for me.
My approach is based on how the supply actually works - it near-shorts the mains near peak of the cycle positive and negative to grab the current in to recharge the reservoir caps at 100Hz for a tiny hit-current pulse. Put a scope on the mains and there is a huge distortion of the waveform caused by it - the power amp draws most so causes most noise.
Anyway so far my approach has always worked in all systems - unless you don’t mind lumpy boomy bass - or have small speakers that may not have the issue.
I think the star-earth with mains is overrated - there should be nothing on the earth unless you have a fault. It is the configuration of the wires actually carrying the juice that matters (L and N) IMO, the mains earth should not be doing a lot other than providing a safe reference voltage for the boxes and the system at one point.
But it probably matters to an extent given all attention to it - but I’m amazed the actual high-current wiring with many of orders of magnitude more EM and noise effects gets little mention, as I’ve found it rather critical of what physical topology you adopt.
They don’t disappear but if you control the speakers better they won’t interact as much with the system is what I’ve always consistently found.
A less-capable amp will give you more boom that something with higher damping factor onto the back-emf from the interaction of the room resonance with the speaker drive unit - it does have a resonance itself and when you get coupled-oscillations between the room acoustic circuit and the electrical circuit you get a big boomy sound. Fix either the electrical or room and it helps solve the problem - but it is not just a perfect HiFi system and only the room to consider.
Hi DB.
With all due respect I will gracefully bow out of further discussion of cause and effect of the interesting subject of room acoustics, as our views will turn out to somewhat differ. ATB Peter
I don’t mind people having different views and experiences so no problem!
I’m just genuinely sharing mine. I’m in no way offended if someone has a strong set of opinions - it has no impact on me. I do like learning from other people’s experiences.
Poweramp
2=. 555DR PS
2=. 552 DR PS
with the 2/3 carrying more constant current than 1.
I know that the topology of the cables matters and have commented about it on this thread. The bass did become unpleasant until I tidied the ones on the carpet up by keeping them apart and using pipe insulation again. More than three years ago I bought high quality screened Isotek EV03 Platinum cables preferring them to PoweLines then. Because they are 1m and stiff they cross the 400mm gap and sideways to the PSs through the air.
Power Amp PS boxes I’ve found the most important to get the most immediate mains feed - they need most of it and as they run class AB (mainly B) then they pull a dynamic load-varying and music varying current.
If you then ‘stand off’ the Amp (or Amps in my case) via a little relatively quiet ‘island’ of tranquility on the mains block then all the class A supply items plugged into that block can find their relation to each other quietly on the block then form a single point of connection with what the Amp is doing on the wall-socket with its noise.
This way you do not superimpose different relative voltages onto each other plugged-in class A item - they all see the same noise voltage from the Power Amp at the mains and hence can better common-mode reject it, rather than let it form current loops through each box.
Just a better way to do it all IMO - and I like the effect.
…but this subject seems to be a can of worms where people get very offended when discussing ideas and electrical physics and start to take personal offense, so I will cease at the above I think.
Use what you find works and personally enjoy - try to help others if they are open and want ideas to try.
None of this needs a Physics degree - you experiment and if it works it works!
Hi DB, you make some interesting points about the fluctuating demands of the power amp(s) and I was not questioning the theory of the benefit of plugging a power amp directly into the wall, just trying to understand the reasons that cause a benefit to SQ and our differing experiences.
I have indeed tried my single 250DR plugged into the wall vs plugged into the G3 and preferred the latter. As you suggest a preference is certainly system and room dependent. Firstly my single 250 DR will certainly draw less current than one, let alone three, 500DRs, and secondly my speakers have never been bass-heavy and work well in a rather small listening room, despite being fairly large floorstanders.
Which could explain the differing results of wall vs block plugging for power amps we are experiencing. Having said all of this, as it is such an easy test, I will certainly double-check and try again the comparison of where to plug my 250DR.
Smaller speakers in a well-behaved room may give different results.
Not wanting to be do more than suggest personal experimentation - easy and you will either waste a little time getting no difference or get better or worse performance.
In general don’t assume anything is what I usually find works best for me - try it - then think it over and try to understand the results - if you are me.
PeterR,
based on DB’s suggestion, I think you really should strip out your room and start again from the walls inwards. It was so quick & easy last time…
… runs for cover with hard hat on.
Enjoy your music from the system as it is, especially with it all DR’ed!
Your posts here have been very thought provoking - a big thank you.
If I understand what you are saying it is that the speakers and poweramp form an electrical system with potential to form a resonant circuit. The poweramp design needs to be good enough to cope with these. Some of the problem can be the acoustic coupling of the speakers with the room.
Presumably a system with the say 552/500 behind the front line of the speakers and not experiencing room corner bass modes should be able to cope. Would the PSs be a weak point if just forward of the front line of the speakers?
Are there other feedback mechanisms that need to be addressed? Perhaps some on the electric supply side that the mains block can help with?
Whilst I agree with what DB says in the above quote although, not that I am expecting any, it would be interesting what Naim has to say on this topic if anything.
As people have some strong rather fixed views on these subjects I don’t want to say much more.
But there exist both mechanical and electrical ‘circuits’ - meaning they circulate energy in vibrational or electrical ways and have the same concepts - exactly the same - of resonance and damping with the associated damping factor concepts.
Where these two worlds interface at the loudspeaker for an obvious example, then it is both-ways in that the speaker drives the electricity into the room via transduction of electrical to mechanical energy - where it then will form an interaction with the room geometry and the different modes it is supporting and how they are controlled, damped too much or too little and the frequency-dependence and linearity of all that.
But the loudspeaker as transducer works both ways and the room will also work with the drive units to produce an electrical signal between it and all things it can interact with electrically. In a passive system there is a crossover full of reactive components it will see first, then at the end of the speaker cable the Amp and eventually the power supply of the Amp. They are all connected. Why does the DR upgrade improve the bass if it is ‘just the PS’ they all knit together into a connected chain.
So the usual things you get with Active systems - better bass control for example - especially in the deeper bass in preventing harmonic distortion and controlling the back-emf from the drive unit interaction with the room and its resonances.
This is due to better damping factor and no reactive components (apart from the drive unit itself) to form resonances. Resonances are a very big deal - they exist everywhere and in everything and the fact you can store vast amounts of energy into them and then release it over time is one of the engineering challenges for good replay with respect to HiFi.
…there is a lot to it - all very interesting!
The problem can be that if you pick-up one part of this set of connected systems and do not cognise it is connected you can pay a lot of attention to either the HiFi alone and forget the room - or visa-versa.
These are meant to be constructive musings to help promote some intelligent though on it all.
Thanks again - very interesting post. Your first post got me thinking about a puzzle of the last week where to do the tax siting on the sofa I had the monitor about 3 feet (900 mm) from the right hand speaker at about 45 degrees to the axis. There was some bass hardness and other sound changes. Equilibrium restored.
has anyone put an oscilloscope onto the mains to see whether the audio signal is present there (which you would expect to be the case if the 500 is sucking so much juice that it is affecting other components)?
Years ago I did something a little like this on a Japanese transistor radio - I put a 'scope onto the power rails just after the rectifier bridge, and could see the same waveform as that which came from the speaker.
Yes - done that - you get more current-spike on the charging section when the rectifier diodes are conducting to re-fill the smoothing caps inside the PS, as you expect. It is mainly on the charging small part of the mains waveform near the sine wave peak as the other non-conducting (off-diode) is just conducting via its capacitance at very high frequencies only.
So all the supplies can ‘talk’ to each other when they are each in the conduction part of the mains cycle and the noisiest low impedance local noise producer (usually Power Amp) will impose its mains waveform on the other supplies.
The Power Amp also conducts longer to get more current so cuts-in before the other supplies that need relatively little top-up near the top-end of the mains cycle.
The ‘on-off’ conduction transients create the most noise, so that begins it - then the noise settles a bit while conducting - then the other lower current supplies bite to take their own top-up near the top of the mains cycle - then their supply rectifier diodes all stop conducting when the mains cycle drops after sinewave peaks and reverses.
If you consider this, then the sensible thing is to try to avoid the noisy ‘on’ transient spike if possible.
Yes it is all there to be seen (and heard) - lots of current drawn on the ‘on’ conduction transient will cause voltage noise on mains.
So I have spread my big PSs around the entire block of double sockets as shown below. First I just moved the NAC 552 (PowerLine) and 555 DR PS (Red cable) down to middle. Better bass and fuller overall sound but slightly blurry.
Then I moved the 555DR PS down to bottom to join the nDAC (Powerline Lite) instead of the Innuos Zenith. That got rid of the slightly blurry aspect. The nDAC and it’s 555DR get similar mains noise.
So happy with more prominent bass that is soft and textured playing Dido’s Still on My Mind. The only thing I have to do is ensure that the Rega Aria phonostage sounds good (it is currently sandwiched between the 552 and 555).
Getting back to the G3, do those who have it notice any differences dependent on the socket order. Some have put the poweramp back in the wall socket, which is what DB prefers.
Yes.
The power Amp PS will draw mains directly from a lower impedance and resistance - I say ‘impedance’ because it encompasses the reactive components which are rather important in shaping the nose-voltages between the other supplies and the Power Amp PS.
Then having the block (and its plugged-in items) ‘stood-off’ from the wall and all that noise will mean they get more impedance at high frequencies to blunt the voltage spike - and just as important the same Power Amp mains noise spike is seen by all other PS items on the block together and since there will be no relative difference between plugs from that spike there will not be evoked an current loop into the boxes.
…that is my thinking - I’m not claiming it will be ‘best’ for all and even preferred, just why I do it for me and it works for me.
Well the ears say the Aria sounds better powered of the same ring main socket as the RP10 TTPSU! Pretty obvious as it misses the noises from those big Naim PSs. Maybe they are better without the Aria also.
So you think the house stuff is the enemy and it turns out it’s the Naim PSs! Maybe I take the Innuos Zenith off as well!
